Dynamic multi-link operation

Abstract

A non-access point (non-AP) multi-link device (MLD) transmits to an AP MLD a first frame indicating activation of an enhanced multi-link single radio (EMLSR) mode of operation at the non-AP MLD. The non-AP MLD listens on a plurality of links and, based on a received signal strength of a signal received via a first link of the plurality of links exceeding a threshold, switches from the listening mode / state to the frame exchange mode / state on the first link. After switching to the frame exchange mode / state, the non-AP MLD receives from the AP MLD, via the first link, a second frame comprising more than one spatial stream.

Description

Docket No.: 25-3020PCTTITLEDynamic Multi-link OperationCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 790,799, filed April 18, 2025, and U.S. Provisional Application No.63 / 802,727, filed May 9, 2025, all of which are hereby incorporated by reference in their entireties.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 of a Quality of Service (QoS) null frame indicating buffer status information.

[0007] FIG. 5 illustrates an example format of a physical layer (PHY) protocol data unit (PPDU).

[0008] FIG.6 illustrates an example that includes buffer status reporting by STAs, scheduling by an AP of uplink multiuser (MU) transmissions, and transmission of scheduled uplink transmissions by the STAs.

[0009] FIG. 7 illustrates an example reference model for a multi-link device (MLD).

[0010] FIG. 8 illustrates an example of an AP MLD and an associated non-AP MLD.

[0011] FIG. 9 illustrates an example of a multi-link setup between an AP MLD and a non-AP MLD.

[0012] FIG. 10 illustrates an example of a traffic identifier (TID)-to-link mapping in a multi-link communication environment.

[0013] FIG. 11 illustrates an example multi-link configuration between an AP MLD and a non-AP MLD that includes an extremely high frequency link.

[0014] FIG. 12 illustrates a non-High Throughput (non-HT) PPDU.

[0015] FIG. 13 illustrates PPDU formats which may be used for communication over a 60 GHz or millimeter wave (mmWave) link.

[0016] FIG. 14 illustrates enhanced multi-link single radio (EMLSR) operation.

[0017] FIG. 15 illustrates dynamic power save (DPS) operation.

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

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

[0020] FIG. 18 illustrates a further example operation according to an embodiment.

[0021] FIG. 19 illustrates an example trigger frame which may be used according to embodiments.

[0022] FIG. 20 illustrates example null data PPDU (NDPs) which may be used in embodiments.

[0023] FIG. 21 illustrates an example process according to an embodiment.Docket No.: 25-3020PCT

[0024] FIG. 22 illustrates another example process according to an embodiment.DETAILED DESCRIPTION

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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 thatDocket No.: 25-3020PCTthe 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 “employi ng / 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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 behavioral ly 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 ofDocket No.: 25-3020PCTprogrammable 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.

[0033] FIG. 1 illustrates example wireless communication networks in which embodiments of the present disclosure may be implemented.

[0034] 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.

[0035] 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.

[0036] 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).

[0037] 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.

[0038] 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).

[0039] For example, in FIG. 1, STAs 106-4, 106-5, and 106-6 maybe 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 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.

[0040] 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.Docket No.: 25-3020PCTFor example, the term “user"’ maybe 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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-transi tory 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.Docket No.: 25-3020PCT

[0046] 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.

[0047] 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.

[0048] As shown in FIG. 3, a MAC frame includes a MAC header, a variable length frame body, and a frame check sequence (FCS).

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] The power management subfield is used to indicate the power management mode of a STA.Docket No.: 25-3020PCT

[0057] 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.

[0058] The protected frame subfield is set to 1 if the frame body field contains information that has been processed by a cryptographic encapsulation algorithm.

[0059] The +HTC subfield indicates that the MAC frame contains an HT control field.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.Docket No.: 25-3020PCT

[0065] 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.

[0066] 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.

[0067] FIG. 4 illustrates an example of a QoS null frame indicating buffer status information. A QoS null frame refers to a QoS data frame with an empty frame body. A QoS null frame includes a QoS control field and an optional HT control field which may contain a buffer status report (BSR) control subfield. A QoS null frame indicating buffer status information may be transmitted by a STA to an AP.

[0068] The QoS control field may include a traffic identifier (TID) subfield, an ack policy indicator subfield, and a queue size subfield (or a transmission opportunity (TXOP) duration requested subfield).

[0069] The TID subfield identifies the TC or TS of traffic for which a TXOP is being requested, through the setting of the TXOP duration requested or queue size subfield. The encoding of the TID subfield depends on the access policy (e.g., Allowed value 0 to 7 for enhanced distributed channel access (EDCA) access policy to identify user priority for either TC or TS).

[0070] The ack policy indicator subfield, together with other information, identifies the acknowledgment policy followed upon delivery of the MPDU (e.g., normal ack, implicit block ack request, no ack, block ack, etc.)

[0071] The queue size subfield is an 8-bit field that indicates the amount of buffered traffic for a given TC or TS at the STA for transmission to the AP identified by the receiver address of the frame containing the subfield. The queue size subfield is present in QoS null frames sent by a STA when bit 4 of the QoS control field is set to 1. The AP may use information contained in the queue size subfield to determine t TXOP duration assigned to the STA or to determine the uplink (UL) resources assigned to the STA.

[0072] In a frame sent by or to a non-High Efficiency (non-HE) STA, the following rules may apply to the queue size value:The queue size value is the approximate total size, rounded up to the nearest multiple of 256 octets and expressed in units of 256 octets, of all MSDUs and A-MSDUs buffered at the STA (excluding the MSDU or A-MSDU contained in the present QoS Data frame) in the delivery queue used for MSDUs and A-MSDUs with TID values equal to the value indicated in the TID subfield of the QoS Control field.A queue size value of 0 is used solely to indicate the absence of any buffered traffic in the queue used for the specified TID.A queue size value of 254 is used for all sizes greater than 64768 octets.A queue size value of 255 is used to indicate an unspecified or unknown size.

[0073] In a frame sent by an HE STA to an HE AP, the following rules may apply to the queue size value.

[0074] The queue size value, QS, is the approximate total size in octets, of all MSDUs and A-MSDUs buffered at the STA (including the MSDUs or A-MSDUs contained in the same PSDU as the frame containing the queue size subfield)Docket No.: 25-3020PCTin the delivery queue used for MSDUs and A-MSDUs with TID values equal to the value indicated in the TID subfield of the QoS control field.

[0075] The queue size subfield includes a scaling factor subfield in bits B14-B15 of the QoS control field and an unsealed value, UV, in bits B8-B13 of the QoS control field. The scaling factor subfield provides the scaling factor, SF.

[0076] A STA obtains the queue size, QS, from a received QoS control field, which contains a scaling factor, SF, and an unsealed value, UV, as follows:QS =16 xQ ', if SF is equal to O;1024 + 256 x C / V, if SF is equal to 1 ;16408 + 2048 x W, if SF is equal to 2;148480 + 32768 x UV, if SF is equal to 3 and UV is less than 62;> 2147328, if SF equal to is 3 and UV is equal to 62;Unspecified or Unknown, if SF is equal to 3 and UV is equal to 63.

[0077] The TXOP duration requested subfield, which may be included instead of the queue size subfield, indicates the duration, in units of 32 microseconds (us), that the sending STA determines it needs for its next TXOP for the specified TID. The TXOP duration requested subfield is set to 0 to indicate that no TXOP is requested for the specified TID in the current service period (SP). The TXOP duration requested subfield is set to a nonzero value to indicate a requested TXOP duration in the range of 32 us to 8160 us in increments of 32 us.

[0078] The HT control field may include a BSR control subfield which may contain buffer status information used for UL MU operation. The BSR control subfield may be formed from an access category index (ACI) bitmap subfield, a delta TID subfield, an ACI high subfield, a scaling factor subfield, a queue size high subfield, and a queue size all subfield of the HT control field.

[0079] The ACI bitmap subfield indicates the access categories (ACs) for which buffer status is reported (e.g ., B0: best effort (AC_BE), B1: background (AC_BK), B2: video (AC_VI), B3: voice (AC_VO), etc.). Each bit of the ACI bitmap subfield is set to 1 to indicate that the buffer status of the corresponding AC is included in the queue size all subfield, and set to 0 otherwise, except that if the ACI bitmap subfield is 0 and the delta TID subfield is 3, then the buffer status of all 8 TIDs is included.

[0080] The delta Tl D subfield, together with the values of the AC I bitmap subfield, indicate the number of Tl Ds for which the STA is reporting the buffer status.

[0081] The ACI high subfield indicates the ACI of the AC for which the BSR is indicated in the queue size high subfield. The ACI to AC mapping is defined as ACI value 0 mapping to AC BE, ACI value 1 mapping to AC_BK, ACI value 2 mapping to AC_VI, and ACI value 3 mapping to AC_V0.

[0082] The scaling factor subfield indicates the unit SF, in octets, of the queue size high and queue size all subfields.Docket No.: 25-3020PCT

[0083] The queue size high subfield indicates the amount of buffered traffic, in units of SF octets, for the AC identified by the ACI high subfield, that is intended for the STA identified by the receiver address of the frame containing the BSR control subfield.

[0084] The queue size all subfield indicates the amount of buffered traffic, in units of SF octets, for all ACs identified by the ACI Bitmap subfield, that is intended for the STA identified by the receiver address of the frame containing the BSR control subfield.

[0085] The queue size values in the queue size high and queue size all subfields are the total sizes, rounded up to the nearest multiple of SF octets, of all MSDUs and A-MSDUs buffered at the STA (including the MSDUs or A-MSDUs contained in the same PSDU as the frame containing the BSR control subfield) in delivery queues used for MSDUs and A-MSDUs associated with AC(s) that are specified in the ACI high and ACI bitmap subfields, respectively.

[0086] A queue size value of 254 in the queue size high and queue size all subfields indicates that the amount of buffered traffic is greater than 254 x SF octets. A queue size value of 255 in the queue size high and queue size all subfields indicates that the amount of buffered traffic is an unspecified or unknown size. The queue size value of QoS data frames containing fragments may remain constant even if the amount of queued traffic changes as successive fragments are transmitted

[0087] MAC service provides peer entities with the ability to exchange MSDUs. To support this service, a local MAC uses the underlying PHY-level service to transport the MSDUs to a peer MAC entity. Such asynchronous MSDU transport is performed on a connectionless basis.

[0088] FIG. 5 illustrates an example format of a PPDU. As shown, the PPDU may include a PHY preamble, a PHY header, a PSDU, and tail and padding bits.

[0089] The PSDU may include one or more MPDUs, such as a QoS data frame, an MMPDU, a MAC control frame, or a QoS null frame. In the case of an MPDU carrying a QoS data frame, the frame body of the MPDU may include a MSDU or an A-MSDU.

[0090] By default, MSDU transport is on a best-effort basis. That is, there is no guarantee that a transmitted MSDU will be delivered successfully. However, the QoS facility uses a traffic identifier (TID) to specify differentiated services on a per-MSDU basis.

[0091] A STA may differentiate MSDU delivery according to designated traffic category (TC) or traffic stream (TS) of individual MSDUs. The MAC sublayer entities determine a user priority (UP) for an MSDU based on a TID value provided with the MSDU. The QoS facility supports eight UP values. The UP values range from 0 to 7 and form an ordered sequence of priorities, with 1 being the lowest value, 7 the highest value, and 0 falling between 2 and 3.

[0092] An MSDU with a particular UP is said to belong to a traffic category with that UP. The UP may be provided with each MSDU at the medium access control service access point (MAC SAP) directly in a UP parameter. An A-MPDU may include MPDUs with different TID values.

[0093] A STA may deliver buffer status reports (BSRs) to assist an AP in allocating UL MU resources. The STA may either implicitly deliver BSRs in the QoS control field or BSR control subfield of any frame transmitted to the APDocket No.: 25-3020PCT(unsolicited BSR) or explicitly deliver BSRs in a frame sent to the AR in response to a BSRP Trigger frame (solicited BSR).

[0094] The buffer status reported in the QoS control field includes a queue size value for a given TID. The buffer status reported in the BSR control field includes an ACI bitmap, delta TID, a high priority AC, and two queue sizes.

[0095] A STA may report buffer status to the AR, in the QoS control field, of transmitted QoS null frames and QoS data frames and, in the BSR control subfield (if present), of transmitted QoS null frames, QoS data frames, and management frames as defined below.

[0096] The STA may report the queue size for a given TID in the queue size subfield of the QoS control field of transmitted QoS data frames or QoS null frames; the STA may set the queue size subfield to 255 to indicate an unknown / unspecified queue size for that TID. The STA may aggregate multiple QoS data frames or QoS null frames in an A-MPDU to report the queue size for different TIDs.

[0097] The STA may report buffer status in the BSR control subfield of transmitted frames if the AP has indicated its support for receiving the BSR control subfield.

[0098] A High-Efficiency (HE) STA may report the queue size for a preferred AC, indicated by the ACI high subfield, in the queue size high subfield of the BSR control subfield. The STA may set the queue size high subfield to 255 to indicate an unknown / unspecified queue size for that AC.

[0099] A HE STA may report the queue size for ACs indicated by the ACI bitmap subfield in the queue size all subfield of the BSR control subfield. The STA may set the queue size all subfield to 255 to indicate an unknown / unspecified BSR for those ACs.

[0100] FIG.6 illustrates an example that includes buffer status reporting by STAs, scheduling by an AP of uplink multiuser (MU) transmissions, and transmission of scheduled uplink transmissions by the STAs.

[0101] As shown, the AP may solicit one or more associated STAs (STA 1 and STA 2) for buffer status by sending a buffer status report poll (BSRP) trigger frame. Upon receiving the BSRP trigger frame, STA 1 and / or STA 2 may each generate a trigger-based (TB) PPDU if the BSRP trigger frame contains, in a User Info field, the 12 LSBs of the STA’s AID.

[0102] STA 1 and / or STA 2 may each include in the TB PPDU one or more QoS null frames. The one or more QoS null frames may contain one or more QoS control fields or one or more BSR control subfields.

[0103] As described earlier, a QoS control field may include a queue size subfield for a TID for which the STA has a queue size to report to the AP. For example, as shown in FIG.6, STA 1 may respond to the BSRP trigger frame from the AP by transmitting an A-MPDU including multiple QoS null frames. The QoS null frames each indicates, in its respective QoS control field, a queue size for a respective TID, e.g. TID 0 and TID 2. Similarly, STA 2 may respond to the BSRP trigger frame by transmitting an MPDU including a QoS null frame, which indicates a queue size for TID 2 in its QoS control field.

[0104] A BSR control subfield may include a queue size all subfield indicating the queue size for the ACs, indicated by the ACI bitmap subfield, for which the STA has a queue size to report to the AP if the AP has indicated its support forDocket No.: 25-3020PCTreceiving the BSR control subfield. The STA sets a delta TID, a scaling factor, an ACI high, and the queue size high subfields of the BSR Control subfield.

[0105] On receiving the BSRs from STA 1 and STA 2, the AP may transmit a basic trigger frame to allocate UL MU resources to STA 1 and STA 2. In response, STA 1 may transmit a TB PPDU containing QoS data frames with TID 0 and Tl D 2 and STA 2 may transmit a TB PPDU containing one or more QoS data frame(s) with Tl D. The AP may acknowledge the transmitted TB PPDUs from STA 1 and STA 2 by sending a multi-STA block ack frame.

[0106] FIG. 7 illustrates an example reference model for a multi-link device (MLD).

[0107] An MLD is an entity capable of managing communication over multiple links. The MLD may be a logical entity and may have more than one affiliated station (STA). An MLD may be an access point MLD (AP MLD) where a STA affiliated with the MLD is an AP STA (or an AP). An MLD may be a non-access point MLD (non-AP MLD) where a STA affiliated with the MLD is a non-AP STA (or an STA).

[0108] Communication across different frequency bands / channels may occur simultaneously, or not, depending on the capabilities of both of the communicating AP MLD and non-AP MLD.

[0109] As shown in FIG. 7, a MLD may have a single MAC service access point (MAC-SAP) to the LLC layer, which includes a MAC data service. The MLD may support multiple MAC sublayers, coordinated by a sublayer management entity (SME). Each AP STA (or non-AP STA) affiliated with an AP MLD (or non-AP MLD) has a different MAC address within the MLD.

[0110] The SME is responsible for coordinating the MAC sublayer management entities (MLMEs) of the affiliated STAs of the MLD to maintain a single robust security network association (RSNA) key management entity as well as a single IEEE 802.1X Authenticator or Supplicant for multi-link operation (MLO).

[0111] Multi-link operation (MLO) procedures allow a pair of MLDs to discover, synchronize, (de)authenticate, (re)associate, disassociate, and manage resources with each other on any common bands or channels that are supported by both MLDs. The Authenticator and the MAC-SAP of an AP MLD may be identified by the same AP MLD MAC address. The Supplicant and the MAC-SAP of a non-AP MLD may be identified by the same non-AP MLD MAC address.

[0112] FIG. 8 illustrates an example of an AP MLD and an associated non-AP MLD.

[0113] As shown, the AP MLD has two affiliated APs (AP1 and AP2), and the non-AP MLD has two affiliated STAs (STA 1 and STA 2). The AP MLD and the non-AP MLD may be communicatively coupled by two links (Link 1 and Link 2.) Link 1 is established between AP1 and STA1, and link 2 is established between AP2 and STA2.

[0114] Generally, the MAC addresses of an MLD and of its affiliated STAs are different from one another. For example, as shown in FIG. 8, the AP MLD may have MAC address M, AP 1 may have MAC address w, and AP2 may have with MAC address x. Similarly, the non-AP MLD may have MAC address P, STA 1 may have MAC address y, and STA2 may have MAC address z.

[0115] As shown in FIG.8, with each MLD, the MAC sublayer may be further divided into an MLD upper MAC sublayer and an MLD lower MAC sublayer. The MLD upper MAC sublayer (MLD) performs functionalities that are common acrossDocket No.: 25-3020PCTall links. The MLD lower MAC sublayer performs functionalities that are local to each link. Some of the functionalities require joint processing of both the MLD upper and the MLD lower MAC sublayers.

[0116] The MLD upper MAC sublayer functions may include:Authentication, association, and reassociation (between an AP MLD and a non-AP MLD);Security association (e.g., pairwise master key security association (PMKSA), pairwise transient key security association (PTKSA)) and distribution of group temporal key (GTK) I integrity GTK (IGTK) I beacon IGTK (BIGTK);Sequence number (SN) I packet number ( PN) assignment for frames to be encrypted by pairwise transient key (PTK) for unicast frames;Encryption / decryption using PTK for unicast frames;Selection of the MLD lower MAC sublayer for transmission (TID-to-link mapping);Reordering of packets to ensure in-order delivery per each Block Ack session;Block Ack scoreboarding for individually addressed frames (in collaboration with the MLD lower MAC sublayer); optionally, the MLD upper MAC sublayer delivers the Block Ack record on one link to the MLD lower MAC sublayer of other links; andMLD level management information exchange / indication via the MLD lower MAC sublayer

[0117] The MLD lower MAC sublayer functions may include:Maintenance of link specific GTK / I GTK / B IGTK (between an AP affiliated with the AP MLD and a STA affiliated with the non-AP MLD);Link-specific encryption / decryption / integrity protection and PN assignment using GTK / IGTK / BIGTK (between an AP affiliated with the AP MLD and a STA affiliated with the non-AP MLD);Link specific management information exchange / indication (e.g., beacon);Link specific control information exchange / indication (e.g., RTS / CTS, acknowledgements, etc.);Power save state and mode;MAC address filtering for frame reception; andBlock Ack scoreboarding for individually addressed frames (in collaboration with the MLD upper MAC sublayer); optionally, the MLD lower MAC sublayer receives the Block Ack record on the other links from the MLD upper MAC sublayer.

[0118] Multi-link (re)setup between a non-AP MLD and an AP MLD may include an exchange of (re)association request / response frames. A (re)association request / response frame exchange for a multi-link setup may include both frames carrying a basic multi-link element.

[0119] In the (re)association request frame, the non-AP MLD indicates the links that are requested for (re)setup and the capabilities and operational parameters of the requested links. The non-AP MLD may request to (re)set up links with a subset of APs affiliated with the AP MLD. The links that are requested for (re)setup and the capabilities and operation parameters of requested links are independent of existing setup links with an associated AP MLD and the capabilities and operation parameters of setup links.Docket No.: 25-3020PCT

[0120] In the (re)association response frame, the AP MLD may indicate the requested links that are accepted and the requested links that are rejected for (re)setup and the capabilities and operational parameters of the requested links. The AP MLD may accept a subset of the links that are requested for (re)setup. The (re)association response frame is sent to the non-AP STA, affiliated with the non-AP MLD, that sent the (re)association request frame.

[0121] An MLD that requests or accepts multi-link (re)setup for any two links ensures that each link is located on a different nonoverlapping channel. After successful multi-link (re)setup between a non-AP MLD and an AP MLD, the non-AP MLD and the AP MLD set up links for multi-link operation, and the non-AP MLD is (re)associated with the AP MLD. For each setup link, the corresponding non-AP STA affiliated with the non-AP MLD is in the same associated state as the non-AP MLD and is associated with a corresponding AP affiliated with the AP MLD. For each setup link, functionalities between a non-AP STA and its associated AP are enabled unless the functionalities have been extended to the MLD level or specified otherwise.

[0122] FIG. 9 illustrates an example of a multi-link setup between an AP MLD and a non-AP MLD. As shown, the AP MLD has three affiliated APs: AP 1 operating in the 2.4 GHz band, AP 2 operating in the 5 GHz band, and AP 3 operating in the 6 GHz band. The non-AP MLD has three affiliated STAs: non-AP STA 1 operating in the 2.4 GHz band, non-AP STA 2 operating in the 5 GHz band, and non-AP STA 3 operating in the 6 GHz band.

[0123] The non-AP MLD may initiate multi-link setup by non-AP STA 1 sending an association request frame to AP 1 affiliated with the AP MLD. In the association request frame, the transmitter address (TA) field is set to the MAC address of non-AP STA 1 and the receiver address (RA) field is set to the MAC address of AP 1. The association request frame includes a basic multi-link element that indicates the MLD MAC address of the non-AP MLD and complete information of non-AP STA 1 , non-AP STA 2, and non-AP STA 3. The association request frame may request the setup of three links between the non-AP MLD and the AP MLD (a link between AP 1 and non-AP STA 1, a link between AP 2 and non-AP STA 2, and a link between AP 3 and non-AP STA 3).

[0124] The AP MLD may respond to the requested multi-link setup by AP sending an association response frame to non-AP STA 1 affiliated with the non-AP MLD. In the association response frame, the TA field is set to the MAC address of the AP 1 and the RA field is set to the MAC address of the non-AP STA 1. The association response frame includes a basic multi-link element that indicates the MLD MAC address of the AP MLD and complete information of AP 1, AP 2, and AP 3. The association response frame signals successful multi-link setup by the setup of three links between the non-AP MLD and AP MLD (link 1 between AP 1 and non-AP STA 1, link 2 between AP 2 and non-AP STA 2, and link 3 between AP 3 and non-AP STA 3).

[0125] By default, all TIDs at the non-AP MLD are mapped to all setup links for both uplink and downlink The TID-to-link mapping mechanism allows an AP MLD and a non-AP MLD that performed or are performing multi-link setup to specify how UL and DL QoS traffic corresponding to different TIDs (e.g., between 0 and 7) may be assigned to the setup links. In a negotiated TID-to-link mapping, a TID may be mapped to a link set, which is a subset of setup links, ranging from a single setup link to all the setup links.Docket No.: 25-3020PCT

[0126] A setup link is defined as enabled for a non-AP MLD if at least one TID is mapped to that link either in DL or in UL, and is defined as disabled if no TIDs are mapped to that link both in DL and UL. At any point in time, a TID is always mapped to at least one setup link both in DL and UL, which means that a TID-to-link mapping change can only be valid and successful if it does not result in a TID having a mapped link set made of zero setup links.

[0127] By default, all setup links are enabled. If a link is enabled for a non-AP MLD, it may be used for the exchange of individually addressed frames, subject to the power state of the non-AP STA operating on that link. Only MSDUs or A-MSDUs with TIDs mapped to a link may be transmitted on that link in the direction (DL / UL) corresponding to the TID-to-link mapping. Individually addressed management frames and control frames may be sent on any enabled link between an affiliated STA of the non-AP MLD and a corresponding AP of the AP MLD, both in DL and UL.

[0128] If a link is disabled for a non-AP MLD, the link may not be used for the exchange of individually addressed frames between an affiliated STA of the non-AP MLD and a corresponding AP of the AP MLD.

[0129] If a TID is mapped in UL to a set of enabled links for a non-AP MLD, the non-AP MLD may use any link within this set of enabled links to transmit individually addressed MSDUs or A-MSDUs corresponding to that TID.

[0130] If a TID is mapped in DL to a set of enabled links for a non-AP MLD, the non-AP MLD may retrieve individually addressed BUs buffered at the AP MLD that are MSDUs or A-MSDUs corresponding to the TID, on any link of the set of enabled links. Conversely, the AP MLD may use any link within the set of enabled links to transmit individually addressed MSDUs or A-MSDUs corresponding to the TID, subject to the power state of the non-AP STA on each of the used link.

[0131] If the default mode is used, the non-AP MLD may retrieve BUs buffered by the AP MLD on any setup link, though the AP MLD may recommend a link.

[0132] A non-AP MLD may retrieve buffered BUs that are MMPDUs buffered at the AP MLD on any enabled link. An AP MLD may use any enabled link to transmit individually addressed bufferable management frames that are not measurement MMPDUs, subject to the power state of the non-AP STA on the used link.If a STA affiliated with a non-AP MLD is in active mode on a link with a set of TIDs mapped for DL transmission, its associated AP affiliated with the AP MLD may transmit to the STA: MSDUs / A-MSDUs for the set of mapped TIDs for the non-AP MLD; and MMPDUs that are not measurement MMPDUs for the non-AP MLD or its affiliated STAs, unless the frames are transmitted to another STA affiliated with the same non-AP MLD and in active mode.

[0133] As mentioned above, under the default mapping mode, all TIDs are mapped to all setup links for DL and UL, and all setup links are enabled. A non-AP MLD and an AP MLD that perform multi-link setup shall operate under this mode if a TID-to-link mapping negotiation for a different mapping has not occurred, was unsuccessful, or was torn down.

[0134] In a multi-link (re)setup procedure, a non-AP MLD may initiate a TID-to-link mapping negotiation by including a TID-to-link mapping element in a (re)association request frame if an AP MLD has indicated support for TID-to-link mapping negotiation.After receiving the (re)association request frame containing the TID-to-link mapping element, the AP MLD may reply to the (re)association request frame in according to the following rules. The AP MLD can accept the requested TID-to-link mapping indicated in the TID-to-link mapping element in the received (re)association request frame only if it accepts theDocket No.: 25-3020PCTmulti-link (re)setup for all links on which at least one TID is requested to be mapped. In this case, the non-AP MLD does include in the (re)association response frame a TID-to-link mapping element. Otherwise, the non-AP MLD indicates rejection of the proposed TID-to-link mapping by including in the (re)association response frame a TID-to-link mapping element that suggests a preferred TID-to-link mapping.

[0135] Following a successful multi-link (re)setup, to negotiate a new TID-to-link mapping, an initiating MLD may send an individually addressed TID-to-link mapping request frame to a responding MLD that has indicated support of TID-to-link mapping negotiation.

[0136] On receiving the individually addressed TID-to-link mapping request frame, the responding MLD sends an individually addressed TID-to-link mapping response frame to the initiating MLD according to the following rules. The responding MLD may accept the requested TID-to-link mapping indicated in the TID-to-link mapping element in the received TID-to-link mapping request frame by transmitting a TID-to-link mapping response frame. Otherwise, the responding MLD may indicate rejection of the proposed TID-to-link mapping in the TID-to-link mapping response frame. The responding MLD may suggest a preferred TID-to-link mapping in the TID-to-link mapping response frame by including the TID-to-link mapping element in the TID-to-link mapping response frame.

[0137] An MLD may suggest a preferred TID-to-link mapping to a peer MLD by sending an unsolicited TID-to-link mapping response frame that includes a TID-to-link mapping element.

[0138] When a peer MLD indicates a preferred TID-to-link mapping, an MLD may take into account the preferred TID-to-link mapping when it initiates a new TID-to-link mapping. In addition, an AP MLD may take into account the traffic flow(s) affiliated with the non-AP MLD and the capabilities and constraints (if any) of the non-AP MLD.

[0139] When two MLDs have negotiated a TID-to-link mapping, either MLD may tear down the negotiated TID-to-link mapping by sending an individually addressed TID-to-link mapping teardown frame. After teardown, the MLDs operates in default mapping mode.

[0140] When an MLD successfully negotiates a TID-to-link mapping with a peer MLD, both the MLD and the peer MLD update an uplink and / or downlink TID-to-link mapping information according to the negotiated the TID-to-link mapping.

[0141] When an MLD has successfully negotiated with a peer MLD an uplink and / or downlink TID-to-link mapping in which the bit position / of a link mapping field n in the Tl D-to-link mapping element is set to 0, a Tl D n shall not be mapped to the link associated with the link ID / in uplink and / or downlink. When an MLD has successfully negotiated with a peer MLD an uplink and / or downlink TID-to-link mapping in which the bit position / of a link mapping field n in the TID-to-link mapping element is set to 1 , the TID n is mapped to the link associated with the link ID / in uplink and / or downlink.

[0142] FIG. 10 illustrates an example of a TID-to-link mapping in a multi-link communication environment. As shown, the multi-link communication environment includes an AP MLD having three affiliated APs and a non-AP MLD having three affiliated STAs.

[0143] During or after multi-link setup, the non-AP MLD and the AP MLD may negotiate a TID-to-link mapping. The TID-to-link mapping maps TIDs at the non-AP MLD in UL and DL to setup links between the AP MLD and the non-AP MLD. For example, as shown in FIG. 10, the TID-to-link mapping may map TIDs 0-6 in both ULand DL to link 1 and TIDDocket No.: 25-3020PCT7 in both UL and DL to link 2. As such, links 1 and 2 are enabled, and link 3 is disabled. The TID-to-link mapping negotiation may be performed by exchanging an association request / response frame or a TID-to-link mapping request / response frame between the non-AP MLD and the AP MLD.

[0144] FIG. 11 illustrates an example multi-link configuration, between an AP MLD and a non-AP MLD, that includes an EHF link. As shown, the AP MLD has four affiliated APs: AP 1 operating in the 2.4 GHz band, AP 2 operating in the 5 GHz band, AP 3 operating in the 6 GHz band, and AP 4 operating in the 60 GHz band. The non-AP MLD has four affiliated STAs: non-AP STA 1 operating in the 2.4 GHz band, non-AP STA 2 operating in the 5 GHz band, non-AP STA 3 operating in the 6 GHz band, and non-AP STA 4 operating in the 60 GHz band.

[0145] The non-AP MLD may perform a multi-link (re)setup (as described above with reference to FIG. 9) to (re)setup multiple links with AP MLD. After successful multi-link (re)setup between the non-AP MLD and the AP MLD, the non-AP MLD becomes associated with the AP MLD and multiple links are set up between the non-AP MLD and the AP MLD. More specifically, for each setup link, the corresponding non-AP STA affiliated with the non-AP MLD becomes associated with the corresponding AP affiliated with the AP MLD. For example, in FIG. 11, the AP MLD may perform a multi-link (re)setup to set up multiple links from among a plurality of links, comprising a first link (link 1), a second link (link 2), a third link (link 3), and a fourth link (link 4). In an example, link 1, link 2, link 3, and link 4 may correspond respectively to a 2.4 GHz link, a 5 GHz link, a 6 GHz link, and a 60 GHz link. The 2.4 GHz, 5 GHz, and 6 GHz links are non-EHF links, and the 60 GHz link is an EHF link. At the end of the multi-link (re)setup, the non-AP MLD is associated with the AP MLD and links 1 , 2, and 3 are setup between non-AP MLD and AP MLD. Specifically, non-AP STA 1 is associated with AP 1, non-AP STA 2 is associated with AP 2, and non-AP STA 3 is associated with AP 3.

[0146] In an example, the non-AP MLD may request the setup of links 1 , 2, and 3 in the multi-link (re)setup and the AP MLD may accept the request resulting in the setup of links 1 , 2, and 3. In another example, the non-AP MLD may request the setup of links 1, 2, 3, and 4 and the AP MLD may accept the setup of links 1, 2, and 3 but not of link 4. Link 4 may thus remain not setup as shown in FIG. 11. Setup links may then be enabled by mapping to each one or more TIDs as described above with reference to FIG. 10.

[0147] In an example, the non-AP MLD may request the setup of link 4 with the AP MLD after performing the (re)setup that results in the setup of links 1 , 2, and 3 as shown in FIG. 11. In an implementation, the non-AP MLD may request link reconfiguration of the ML setup by sending a Link Reconfiguration Request frame to the AP MLD. The non-AP MLD may send the Link Reconfiguration Request frame from an affiliated non-AP STA to the corresponding AP affiliated with the AP MLD. To indicate support of link reconfiguration, the AP MLD may set a Link Reconfiguration Operation Support subfield to 1 in an MLD Capabilities And Operations subfield of a Basic Multi-Link element that the AP MLD transmits. The Link Reconfiguration Request frame may contain a Reconfiguration Multi-Link element that includes a Per-STA Profile subelement for each affiliated non-AP STA that the non-AP MLD is requesting to add to its ML setup or delete from its ML setup. For example, in FIG. 11, a Reconfiguration Multi-Link element included in the Link Reconfiguration Request frame from the non-AP MLD may include a Per-STA Profile subelement for non-AP STA 4. The Per-STA Profile subelement for non-AP STA 4 may include, for example, a Link ID subfield set to a link identifier of AP 4 operating on linkDocket No.: 25-3020PCT4 that the non-AP MLD is requesting to add; an NSTR (non-simultaneous transmit and receive) Indication Bitmap Present bit set to 1 if at least one NSTR link pair that includes link 4 is present for the non-AP MLD; a STA MAC Address subfield in a STA Info field set to the STA MAC address of non-AP STA 4; and a STA Profile field that includes a complete profile for non-AP STA 4.

[0148] After receiving the Link Reconfiguration Request frame from the non-AP MLD, the AP MLD may respond with a Link Reconfiguration Response frame. The AP MLD may validate an OCI element included in the Link Reconfiguration Request frame before sending the Link Reconfiguration Response frame to the non-AP MLD. The AP MLD may send the Link Reconfiguration Response frame via the same link on which the AP MLD receives the Link Reconfiguration Request frame. If the AP MLD accepts link addition for one or more links, the AP MLD may include in the Link Reconfiguration Response frame a Basic Multi-Link element that includes a Per-STA Profile subelement for each AP operating on a link that is accepted by the AP MLD for addition to the ML setup of the non-AP MLD. For example, in FIG. 11 , if the AP MLD accepts the addition of link 4, the AP MLD may include in the Link Reconfiguration Response frame a Basic Multi-Link element that include a Per-STA Profile subelement for AP 4.

[0149] After sending a Link Reconfiguration Response frame to the non-AP MLD indicating SUCCESS status for an add link operation and receiving an acknowledgement for the response frame from the non-AP MLD, the AP MLD shall consider that link to be added to the ML setup of the associated non-AP MLD.

[0150] FIG. 12 illustrates a non-High Throughput (non-HT) PPDU 1200. Non-HT PPDU 1200 may be used by STAs conforming to the IEEE 802.11a standard amendment. As shown in FIG. 12, non-HT PPDU 1200 includes a non-HT Short Training field (L-STF), a non-HT Long Training field (L-LTF), a non-HT Signal field (L-SIG), and a Data field. The L-STF, L-LTF, and L-SIG form a 20 ps preamble of non-HT PPDU 1200.

[0151] The L-STF may be used by a receiver of non-HT PPDU 1200 to synchronize with the carrier frequency and frame timing of a transmitter of non-HT PPDU 1200 and to adjust the receiver signal gain. The L-LTF may be used by the receiver of non-HT PPDU 1200 to estimate channel coefficients in order to equalize the channel response (e.g., amplitude and phase distortion) in both the L-SIG and the Data fields of non-HT PPDU 1200.

[0152] The L-SIG contains parameters needed to demodulate the Data field, which contains a payload of non-HT PPDU 1200. The L-SIG may be equalized using the channel coefficients estimated using the L-LTF and demodulated to obtain the demodulation parameters of the Data field. The Data Field includes one or more symbols each having a duration of 4 ps, where 3.2 ps carry symbol information and 0.8 ps carry a Guard Interval (Gl).

[0153] For non-HT PPDUs, the only supported bandwidth is 20 MHz, which is divided into 64 subcarriers. As such, non-HT PPDU 1200 may be encoded using a subcarrier spacing of 20 M Hz / 64 or 3125kHz.

[0154] FIG. 13 illustrates example PPDUs, 1302, 1304, 1306, and 1308, which may be used for communication over a 60 GHz or millimeter wave (mmWave) link.

[0155] As shown in FIG. 13, PPDU 1302 comprises a legacy Short Training field (L-STF), a legacy Channel Estimation field (L-CEF), a legacy Header field (L-Header), a Universal Signal field (U-SIG), an ultra-high reliability (UHR) Header-Docket No.: 25-3020PCTA, a UHR Short Training field (UHR-STF), a UHR Channel Estimation field (UHR-CEF), a UHR Header-B, a data field, and a Training field (TRN).

[0156] The L-STF, L-CEF, and L-Headerform a non-Enhanced Directional Multi-Gigabit (non-EDMG) portion of PPDU 1302. The non-EDMG portion is provided in PPDU 1302 to enable backward compatibility with devices conforming to the IEEE 802.11 ad standard amendment. Such devices may also operate in the 60 GHz band. Specifically, the L-STF and the L-CEF are provided to enable detection by such devices of PPDU 1302 and the acquisition of carrier frequency and timing. The L-Header contains similar information (with one or more bits re-defined) to a corresponding legacy header field used in an IEEE 802.11ad PPDU. The U-SIG ensures forward compatibility of PPDU 1320. In an implementation, the U-SIG indicates a PHY version identifier, a BSS color, a TXOP duration, a downlink / uplink (DL / UL) flag, and a bandwidth of PPDU 1320. The UHR Header-A may be designed to include indications per STA of RU allocations. The UHR Header-A carries information required to determine the bandwidth, modulation and coding scheme (MCS), and number of spatial streams of PPDU 1320. The UHR-STF and the UHR-CEF may be used to estimate the channel. The UHR-STF and UHR-CEF field may be present when channel bonding and / or MIMO communication is used in the transmission of PPDU 1320. UHR Header-B is present when multi-user (MU) MIMO (MU-MIMO) is used in the transmission of PPDU 1320. The Data field contains one or more payloads carried by PPDU 1320. The TRN field enables transmit and receive beamforming training and is appended to PPDU 1320 when beamforming is used.

[0157] PPDU 1304 maybe an integrated millimeter wave (IMMW) single user (SU) PPDU; that is, a PPDU which may be used to transmit to a single user / STA on the mmWave link. In an implementation, a bandwidth of PPDU 1304 is equal to 160 MHz, which may be the minimum allowed bandwidth for transmission on the mmWave link. As shown in FIG. 13, PPDU 1304 comprises an L-STF, an L-LTF, a U-SIG, an IMMW-SIG, an IMMW-STF, an IMMW-LTF, a data field, and a packet extension (PE) field. The L-LTF, L-STF, and U-SIG may be identical to those described above for PPDU 1302. The IMMW-SIG field may contain indications per STA of RU allocations. A receiving STA may use the indications in the IMMW-SIG to locate its payload in the data field of PPDU 1304. The IMMW-SIG field may also be used for other indications related to the data field, e.g., modulation and coding scheme (MCS), data type, length, etc. The IMMW-STF and the IMMW-LTF may be used by the receiving STA for channel estimation.

[0158] PPDU 1306 maybe a wide bandwidth version of PPDU 1304. A bandwidth of PPDU 1306 may be equal to 320 MHz, 640 MHz, or 1280 MHz, for example. As shown, the L-STF, L-LTF, U-SIG, and IMMW-SIG are duplicated one or more times in frequency up to the bandwidth of PPDU 1306. The IMMW-STF, the IMMW-LTF, the data field, and the PE use a wider tone plan that covers the bandwidth of PPDU 1306.

[0159] PPDU 1308 may be a duplicated mode version of PPDU 1304. A bandwidth of PPDU 1308 may be equal to 320 MHz, 640 MHz, or 1280 MHz, for example. As shown, in PPDU 1308, PPDU 1302 is duplicated in frequency across all fields.

[0160] FIG. 14 illustrates an example 1400 of enhanced multi-link single radio (EMLSR) operation. As further described, EMLSR operation allows an MLD to support multi-link operation (MLO) using a single radio, which significantly reduces MLO implementation complexity. As shown in FIG. 14, example 1400 includes an AP MLD 1402 and a STA MLD 1404.Docket No.: 25-3020PCTAP MLD 1402 includes an AP 1402-1 and an AP 1402-2. STA MLD 1404 includes a STA 1404-1 and a STA 1404-2. AP 1402-1 and STA 1404-1 operate on a link 1406, and AP 1402-2 and STA 1404-2 operate on a link 1408.

[0161] In an example, STA MLD 1404 operates in EMLSR mode on links 1406 and 1408. Links 1406 and 1408 may thus be referred to as EMLSR links. Specifically, STA MLD 1404 listens to links 1406 and 1408 (simultaneously) during a listening operation and switches to a frame exchange mode on one of links 1406 and 1408 when a switching condition is met. During the listening operation, STA MLD 1404, via STAs 1404-1 and 1404-2, performs clear channel assessment (CCA) on both links 1406 and 1408 to receive an initial control frame (ICF) on one of the links. Typically, the ICE is carried ina non-HT PPDU oranon-HT duplicate PPDU and uses a rate of 6 Mb / s, 12 Mb / s, or 24 Mb / s. At reception of the ICF, the STA, among STAs 1404-1 and 1404-2, operating on the link on which the ICF is received switches to the frame exchange mode to perform the frame exchange initiated by the ICF. During the frame exchange mode, the STA may transmit or receive frames subject to its spatial stream capabilities, operation mode, etc. In an implementation, the STA may respond to the ICF by transmitting an initial control frame (ICR) followed by an exchange of a data frame and a block ack (BA) frame. The STA may return to the listening operation after the frame exchange is finished.

[0162] FIG. 15 illustrates an example 1500 of dynamic power save (DPS) operation. As shown in FIG. 15, example 1500 includes an AP 1502 and a STA 1504. In an example, STA 1504 is associated with AP 1502, and AP 1502 and STA 1504 support DPS mode. In DPS mode, a (AP or non-AP) STA may operate using a low / lower capability mode (LCM) or a high / higher capability mode (HCM). In the LCM, the STA may be in an awake state and may operate with LCM related parameters (e.g., using one or more of: a 20MHz bandwidth (BW), one spatial stream (SS), a limited data rate (e.g., 24 Mb / s) compared with the HCM, a limited PPDU format set compared with the HCM, and a limited control frame set compared with the HCM). This LCM operation allows components (e.g., radio, baseband chip, etc.) of the STA to operate in a lower power mode and thus to reduce power consumption. In the HCM, the STA may also be in an awake state and may operate with HCM related parameters (e.g., using at least one of an operating BW, a number of spatial stream (NSS), and MCSs that are higher than those in LCM). For example, the HCM related parameters may include one or more of: an 80MHz bandwidth, 8 SS, MCS 5~9, EHT / UHR PPDU transmission / reception, data frame / management frame, etc. The STA may transition from LCM to HCM on receiving an ICF transmitted by another STA (associated DPS assisting STA). The ICF may be a frame from a limited set of frame types.

[0163] Example 1500 begins with STA 1504 operating in the LCM. Subsequently, AP 1502 transmits an ICF to STA 1504, which causes STA 1504 to switch to the HCM. In an implementation, AP 1502 transmits the ICF using LCM related parameters (e.g., using a 20 MHz bandwidth, a non-HT PPDU, and with a single spatial stream). In an implementation, STA 1504 switches from the LCM to the HCM after receiving the ICF. In an implementation, STA 1504 may be characterized by a switching delay for switching from the LCM to the HCM, or vice versa. After switching to the HCM, STA 1504 transmits an ICR to AP 1502. After receiving the ICR from STA 1504, AP 1502 may transmit a downlink frame to STA 1504 using HCM related parameters (e.g., using a bandwidth greater than 20 MHz, an HE / EHT / UHR PPDU, any frame type, with multiple spatial streams, a relatively high MCS (e.g., an MCS from 3-9), etc.). STA 1504 may respond toDocket No.: 25-3020PCTthe downlink frame by transmitting a BA to AP 1502. At the end of the frame exchange in the HCM, STA 1504 may return to the LCM.

[0164] As described above, EMLSR operation and / or DPS operation may be used to reduce MLD power consumption. This is particularly true when the MLD supports a mmWave link, which (due to implementation complexity) is significantly more power hungry than a sub-7 GHz link. However, in a current IEEE 802.11bq framework, a minimum bandwidth of 160 MHz has been proposed for IMMW PPDUs. This represents an 8x increase compared to the minimum bandwidth used for sub-7 GHz PPDUs. For ELMS R / DPS operation, this wideband IMMW PPDU requirement means that the EMLSR listening operation / DPS LC mode / state (which is used to receive only control frames) is performed over a 160 MHz operating frequency (compared to only 20 MHz operating frequency on a sub-7 GHz link). This substantially reduces the potential power savings that can be achieved by the use of EMLSR / DPS operation.

[0165] Embodiments of the present disclosure, as further described above, address this problem. In an aspect, a first MLD transmits to a second MLD a first frame activating a mode operation. The mode of operation may comprise a listening mode / state and a frame exchange mode / state. In an example, the mode of operation may include EMLSR operation or DPS mode. In an embodiment, the first MLD operates in the listening mode in a first link of a plurality of links before switching to the frame exchange mode / state in a second link of the plurality of links. In an embodiment, the first MLD operates in the listening mode / state on a plurality of links before switching to the frame exchange mode / state on a link of the plurality of links. In another embodiment, a first STA, affiliated with the first MLD and operating on a first link, operates in an LC mode during the listening mode / state of the mode of operation and in an HC mode during the frame exchange mode / state of the mode of operation. In an embodiment, the first MLD switches from the listening mode / state to the frame exchange mode / state of the mode of operation based on a received signal strength of a signal, received via a first link of the plurality of links, exceeding a threshold. In an embodiment, switching from the listening mode / state to the frame exchange mode / state does not include the first MLD receiving / decoding a frame (e.g., ICF) being transmitted on the first link. Instead, the first MLD switches to the frame exchange mode / state as soon as the first MLD detects on the first link a signal with a signal / receive level greater than or equal to the threshold. As such, the first MLD may spend significantly less time receiving in the listening mode on the first link, enabling a substantial reduction in power consumption during this state / mode. This benefit is especially impactful when the first link is a mmWave link, with considerably higher power demands than a sub-7 GHz link.

[0166] FIG. 16 illustrates an example 1600 of an example operation according to an embodiment. As shown in FIG.16, example 1600 includes an MLD 1602 and an MLD 1604. MLD 1602 may include an AP MLD ora non-AP MLD. MLD 1604 may include an AP MLD or a non-AP MLD. In an example, MLD 1602 include a STA 1602-1 and a STA 1602-2. STAs 1602-1 and 1602-2 are AP STAs when MLD 1602 is an AP MLD, and non-AP STAs when MLD 1602 is a non-AP MLD. In an example, MLD 1604 include a STA 1604-1 and a STA 1604-2. STAs 1604-1 and 1604-2 are AP STAs when MLD 1604 is an AP MLD, and non-AP STAs when MLD 1604 is a non-AP MLD. In example 1600, STA 1602-1 and STA 1604-1 operate on a link 1616, and STA 1602-2 and STA 1604-2 operate on a link 1618.Docket No.: 25-3020PCT

[0167] In example 1600, link 1616 is a sub-7 GHz (2.4 GHz, 5 GHz, or 6 GHz) link. As such, a carrier frequency of link 1616 (or of channel(s) of / within link 1616) fall within a sub-7 GHz band (2.4 GHz, 5 GHz, or 6 GHz band). Link 1618 is a 60 GHz or millimeter wave (mmWave) link. As such, a carrier frequency of link 1618 (or of channel(s) of / within link 1618) fall within a 60 GHz or mmWave band (e.g., between 42 GHz and 71 GHz). STAs 1602-2 and 1604-2 operating on link 1618 may be referred to as IMMW STAs. Embodiments however are not limited by this example.

[0168] Example 1600 begins with MLD 1604 transmitting a frame 1606. In an example, MLD 1604 may transmit frame 1606, via STA 1604-1, on link 1616. In another example, MLD 1604 may transmit frame 1606, via STA 1604-2, on link 1618. In an embodiment, frame 1606 indicates activation of a mode of operation at MLD 1604.

[0169] In an embodiment, the mode of operation comprises enhanced multiple link single radio (EMLSR) operation. Frame 1606 may indicate activation of EMLSR operation for links 1616 and 1618. When MLD 1604 activates EMLSR operation for links 1616 and 1618, links 1616 and 1618 may be referred to as EMLSR links. According to EMLSR operation, MLD 1604 operates in a listening mode / state on links 1616 and 1618 and switches to a frame exchange mode / state on one of links 1616 and 1618 when a switching condition is satisfied / detected.

[0170] In an embodiment, during the listening mode / state, MLD 1604 performs clear channel assessment (CCA) or energy detection (via STAs 1604-1 and 1604-2) on both links 1616 and 1618 until the switching condition is satisfied / detected. In an embodiment, while in the listening mode / state, STAs 1604-1 and 1604-2 monitor / listen and may receive frames (e.g., in a limited capacity) over respective bandwidths. In an example, a first bandwidth used / monitored / listened to by STA 1604-1 during the listening mode / state maybe equal to 20 MHz, 40 MHz, or 80 MHz. In an example, a second bandwidth used / monitored / listened to by STA 1604-2 during the listening mode / state may be narrower than a bandwidth of a PPDU used / transmitted to cause STA 1604-2 to switch from the listening mode / state to the frame exchange mode / state. For example, the second bandwidth may be equal to 20 MHz, while the bandwidth of the PPDU may be equal to 160 MHz. In an embodiment, bandwidth of the PPDU may be equal to a minimum allowed bandwidth for transmission on link 1618. Monitoring / listening to the narrower bandwidth allows STA 1604-2 to reduce its power consumption while in the listening mode / state. In another example, the second bandwidth may be equal to the bandwidth of the PPDU used / transmitted to cause STA 1604-2 to switch from the listening mode / state to the frame exchange mode / state. For example, the second bandwidth may be equal to 160 MHz, which is the bandwidth of the PPDU used / transmitted to cause STA 1604-2 to switch from the listening mode / state to the frame exchange mode / state.

[0171] In an embodiment, the switching condition is satisfied / detected when MLD 1604 receives, via link 1616, a control frame (e.g., IGF) of a first type. In an embodiment, the control frame (e.g., IGF) of the first type is carried in a non-HT PPDU (as illustrated in FIG. 12) or a non-HT duplicate PPDU. In an example, a bandwidth of the non-HT PPDU is 20 MHz and a bandwidth the non-HT duplicate PPDU is 40 MHz. In an example, a rate of the non-HT PPDU or the non-HT duplicate PPDU is 6 Mb / s, 12 Mb / s, or 24 Mb / s.

[0172] In another embodiment, the switching condition is also satisfied / detected when MLD 1604 receives / detects, via STA 1604-2, on link 1618 a signal with a received signal strength (e.g., received signal strength indicator (RSSI)) that exceeds a threshold. In an embodiment, the threshold comprises a CCA energy detect threshold. In an embodiment, theDocket No.: 25-3020PCTthreshold comprises a value between -82dBm and -72 dBm. In an embodiment, the threshold may be equal to -72 dBm when the second bandwidth used by STA 1604-2 during the listening state / mode is narrower than the bandwidth of the PPDU used / transmitted to cause STA 1604-2 to switch from the listening mode / state to the frame exchange mode / state (e.g., the second bandwidth is 20 MHzandthe bandwidth of the PPDU is 160 MHz). In another embodiment, the threshold may be equal to -82 dBm when the second bandwidth used by STA 1604-2 during the listening state / mode is equal to the bandwidth of the PPDU used / transmitted to cause STA 1604-2 to switch from the listening mode / state to the frame exchange mode / state (e.g., the second bandwidth is 160 MHz and the bandwidth of the PPDU is 160 MHz). In an embodiment, the switching condition for link 1618 does not include STA 1604-2 receiving / decoding the frame (e.g., IGF) being transmitted on link 1618. Instead, STA 1604-2 switches to the frame exchange mode / state as soon as STA 1604-2 detects on link 1618 a signal with a signal / receive level greater than or equal to the threshold. This also allows STA 1604-2 to reduce its power consumption while in the listening mode / state. In an example, STA 1604-2 may use the same processing circuitry for listening on link 1616 to listen on link 1618 instead of using a possibly more power hungry processing circuity tailored for listening on link 1618. In an embodiment, parameters included in the frame (e.g., TXOP duration, number of spatial streams, bandwidth, etc.) may be transmitted to MLD 1604 using another frame transmitted via link 1616. In an embodiment, the switching condition for link 1618 may further comprise that STA 1604-2 and STA 1602-2 performed a beamforming training prior to STA 1604-2 switching from the listening mode / state to the frame exchange mode / state. In a further embodiment, the switching condition may further comprise that STA 1604-2 has adapted its receive beam to receive from STA 1602-2 prior to STA 1604-2 switching from the listening mode / state to the frame exchange mode / state.

[0173] In an embodiment, the STA, affiliated with MLD 1604, operating on the link for which the switching condition is satisfied / detected switches from the listening mode / state to the frame exchange mode / state. After switching to the frame exchange mode / state, the STA affiliated with MLD 1604 on that link can transmit or receive frames on the link (subject to its spatial stream capabilities, operation mode, etc.). The STA affiliated with MLD 1604 on the other link may continue to operate in the listening mode / state. MLD 1604 may return to the listening mode / state after an end of the frame exchange on the link for which the switching condition is satisfied / detected.

[0174] In an embodiment, after switching to the frame exchange mode / state, STA 1604-1 can transmit or receive frames over a third bandwidth. The third bandwidth may be equal to or greater than the first bandwidth. In an example, the third bandwidth may be equal to 80 MHz, 160 MHz, or 320 MHz. Additionally, after switching to the frame exchange mode / state, STA 1604-1 may transmit or receive using more than one spatial stream. In an embodiment, after switching to the frame exchange mode / state, STA 1604-2 can transmit or receive frames over a fourth bandwidth. The fourth bandwidth may be equal to or greater than the second bandwidth. In an example, the fourth bandwidth may be equal to 80 MHz, 160 MHz, 320 MHz, 640 MHz, or 1280 MHz. Additionally, after switching to the frame exchange mode / state, STA 1604-2 may transmit or receive using more than one spatial stream.

[0175] In another embodiment, the mode of operation comprises enhanced multiple link multiple radio (EMLMR) operation. A difference between EMLMR and EMLSR is that MLD 1604 has multiple radios in EMLMR instead of a singleDocket No.: 25-3020PCTradio in EMLSR. However, like EMLSR operation, in EMLMR operation, MLD 1604 operates in a listening mode / state on links 1616 and 1618 and switches to a frame exchange mode / state on one of links 1616 and 1618 when a switching condition is satisfied / detected. When MLD 1604 operates in the listening mode / state, each radio of MLD 1604 is used to listen for a respective link of the plurality of links of the MLD. When MLD 1604 operates in the frame exchange mode / state, the multiple radios may be used for the link on which the frame exchange is being performed. Operation in the listening mode / state and the frame exchange mode / state and the switching condition(s) may be the same as described above for EMLSR. In an example, the ICR that causes a STA affiliated with MLD 1604 to switch from the listening mode / state to the frame exchange mode / state has a number of spatial streams (Nss) that satisfies the receiving capabilities of the STA. After the STA switches to the frame exchange mode / state, the STA may receive frames that satisfy the MCS and Nss capabilities indicated by MLD 1604 in an EML Operating Mode Notification frame transmitted on the link on which the ICR was received.

[0176] In a further embodiment, the mode of operation comprises a power save (PS) mode. The PS mode may be a dynamic PS (DPS) mode or a spatial multiplexing PS (SMPS) mode. Frame 1606 may indicate activation of the PS mode for one or more of links 1616 and 1618. In an embodiment, when the PS mode is activated for link 1616, STA 1604-1, affiliated with MLD 1604 on link 1616, operates in a lower capability (LC) mode / state during a listening mode / state of the PS mode and in a higher capability (HC) mode / state during a frame exchange / state mode of the PS mode. STA 1604-1 switches from the LC mode / state to the HC mode / state when a switching condition is detected. In an embodiment, while in the LC mode, STA 1604-1 performs CCA or energy detection on link 1616 until the switching condition is satisfied / detected. In an embodiment, while in the LC mode, STA 1604-1 monitors / listens and may receive frames over a first bandwidth. In an example, the first bandwidth may be equal to 20 MHz, 40 MHz, or 80 MHz. In an embodiment, the switching condition is satisfied / detected when STA 1604-1 receives, via link 1616, an initial control frame (ICF). In an embodiment, the ICF is carried in a non-HT PPDU (as illustrated in FIG. 12). In an example, a bandwidth of the non-HT PPDU is 20 MHz. In an example, a rate of the non-HT PPDU is 24 Mb / s. After switching to the HC mode / state, STA 1604-1 can transmit or receive frames with a second bandwidth. The second bandwidth may be equal to or greater than the first bandwidth. In an example, the second bandwidth may be equal to 80 MHz, 160 MHz, or 320 MHz. In an embodiment, the second bandwidth is equal to a minimum bandwidth of an IMMW PPDU or a bandwidth of a signal (SIG) field of an IMMW PPDU. Additionally, after switching to the HC mode / state, STA 1604-1 may transmit or receive using more than one spatial stream. STA 1604-1 may return to the LC mode / state after an end of the frame exchange on link 1616.

[0177] Similarly, when the PS mode is activated for link 1618, STA 1604-2, affiliated with MLD 1604 on link 1618, operates in an LC mode / state during a listening mode / state of the PS mode and in an HC mode / state during a frame exchange / state mode of the PS mode. STA 1604-2 switches from the LC mode / state to the HC mode / state when a switching condition is detected. In an embodiment, while in the LC mode, STA 1604-2 performs CCA or energy detection on link 1618 until the switching condition is satisfied / detected. In an embodiment, while in the LC mode, STA 1604-2 monitors / listens and may receive frames over a third bandwidth. In an example, the third bandwidth may be equal to 20 MHz, 40 MHz, or 80 MHz. In an embodiment, the switching condition is satisfied / detected when STA 1604-2Docket No.: 25-3020PCTreceives / detects on link 1618 a signal with a received signal strength that exceeds a threshold. In an embodiment, the threshold comprises a CCA energy detect threshold. In an embodiment, the threshold comprises a value between -82dBm and -72 dBm. After switching to the HC mode / state, STA 1604-2 can transmit or receive frames with a fourth bandwidth. The fourth bandwidth maybe equal to or greater than the third bandwidth. In an example, the fourth bandwidth may be equal to 80 MHz, 160 MHz, 320 MHz, 640 MHz, or 1280 MHz. In an embodiment, the fourth bandwidth is equal to a minimum bandwidth of an IMMW PPDU or a bandwidth of a signal (SIG) field of an IMMW PPDU. Additionally, after switching to the HC mode / state, STA 1604-2 may transmit or receive using more than one spatial stream. STA 1604-2 may return to the LC mode / state after an end of the frame exchangeon link 1618.

[0178] Returning to example 1600, after transmitting frame 1606, MLD 1604 may enter the listening mode / state of the mode of operation on one or more of links 1616 and 1618. In example 1600, it is assumed that MLD 1604 enters the listening mode / state on at least link 1618 (60 GHz or mmWave link). Subsequently, MLD 1602 transmits a frame 1608 via link 1618 to cause MLD 1604 to transition to the frame exchange mode / state on link 1618. In an embodiment, frame 1608 may be a control frame (e.g., ICF) of the first type as described above. In an embodiment, the control frame of the first type may comprise an existing sub-7 GHz frame, such as an RTS frame or a trigger frame similar to trigger frame 1900 described further below in FIG. 19. In an embodiment, frame 1608 may be carried in an IMMW SU PPDU as illustrated in FIG. 13 above. In another embodiment, frame 1608 maybe an IMMW SU NDP or an IMMW Wide BWNDP as described further below in FIG. 20. In a further embodiment, frame 1608 may be merely a physical signal (e.g., STF) with a bandwidth of 20, 40, 80, or 160 MHz. STA 1604-2, operating in the listening state / mode, detects a signal (due to frame 1608) on link 1618 and determines that the switching condition for link 1618 is satisfied (e.g., due to a received signal strength of the signal exceeding the threshold described above). As such, as shown in FIG. 16, STA 1604-2 switches from the listening mode / state to the frame exchange mode / state while receiving frame 1608 (and without fully receiving / decoding frame 1608).

[0179] In an embodiment, after switching to the frame exchange state / mode on link 1618, MLD 1604 may transmit a frame (e.g. ICR) 1610 to MLD 1602 via link 1618. In an embodiment, MLD 1604 may transmit frame 1610 within a predetermined duration from the time of detecting, on link 1618, the signal that causes STA 1604-2 to switch to the frame exchange mode / state. In an embodiment, the pre-determined duration is equal to the time required to transmit frame 1608 on link 1618, plus a short interframe space (SIFS), plus the time required to transmit frame 1610 on link 1618.

[0180] Subsequently, MLDs 1602 and 1604 may exchange one or more frames on link 1618. For example, MLD 1602 may transmit to MLD 1604 a frame 1612. Frame 1612 may comprise a data frame. MLD 1604 may respond to frame 1612 by transmitting a frame 1614 to MLD 1602. Frame 1614 may comprise a BA frame. With MLD 1604 operating in the frame exchange state / mode on link 1618, PPDUs carrying frame 1612 and / or 1614 may have a larger bandwidth and / or may comprise more than one spatial stream.

[0181] FIG. 17 illustrates an example 1700 of another example operation according to an embodiment. As shown in FIG. 17, example 1700 includes an MLD 1702 and an MLD 1704. MLD 1702 may include an AP MLD ora non-AP MLD. MLD 1704 may include an AP MLDora non-AP MLD. In an example, MLD 1702 include a STA 1702-1 and a STA 1702-Docket No.: 25-3020PCT2. STAs 1702-1 and 1702-2 are AP STAs when MLD 1702 is an AP MLD, and non-AP STAs when MLD 1702 is a non-AP MLD. In an example, MLD 1704 include a STA 1704-1 and a STA 1704-2. STAs 1704-1 and 1704-2 are AP STAs when MLD 1704 is an AP MLD, and non-AP STAs when MLD 1704 is a non-AP MLD. In example 1700, STA 1702-1 and STA 1704-1 operate on a link 1716, and STA 1702-2 and STA 1704-2 operate on a link 1718.

[0182] In example 1700, link 1716 is a sub-7 GHz (2.4 GHz, 5 GHz, or 6 GHz) link. As such, a carrier frequency of link 1716 (or of channel(s) of / within link 1716) fall within a sub-7 GHz band (2.5 GHz, 6 GHz, or 6 GHz band). Link 1718 is a 60 GHz or millimeter wave (mmWave) link. As such, a carrier frequency of link 1718 (or of channel(s) of / within link 1718) fall within a 60 GHz or mmWave band (e.g., between 42 GHz and 71 GHz). STAs 1702-2 and 1704-2 operating on link 1718 may be referred to as IMMW STAs. Embodiments however are not limited by this example.

[0183] Example 1700 begins with MLD 1704 transmitting a frame 1706. In an example, MLD 1704 may transmit frame 1706, via STA 1704-1, on link 1716. In another example, MLD 1704 may transmit frame 1706, via STA 1704-2, on link 1718. In an embodiment, frame 1706 indicates activation of a mode of operation at MLD 1704. In an embodiment, the mode of operation comprises EMLSR operation, EMLMR operation, and / or a PS mode (e.g., DPS or SMPS) as described above. As described above, in EMLSR operation, MLD 1704 operates in a listening mode / state on links 1716 and 1718 and switches to a frame exchange mode / state on one of links 1716 and 1718 when a switching condition is satisfied / detected. As described above, when the PS mode is activated for link 1716 (1718), STA 1704-1 (1704-2), affiliated with MLD 1704 on link 1716 (1718), operates in an LC mode / state during a listening mode / state of the PS mode and in an HC mode / state during a frame exchange / state mode of the PS mode. STA 1704-1 (1704-2) switches from the LC mode / state to the HC mode / state when a switching condition is detected.

[0184] In an embodiment, STA 1704-1 performs similar operations in the listening state / mode of the mode of operation (eg., EMLSR, EMLMR, PS mode) as described above with respect to STA 1604-1 and switches from the listening mode / state to the frame exchange mode / state for the same switching conditions described above with respect to STA 1604-1. In an embodiment, STA 1704-1 perform similar operations in the frame exchange mode / state of the mode of operation (e.g., EMLSR, EMLMR, PS mode) as described above with respect to STA 1604-1. For the sake of brevity, the description of these operations is not repeated herein and is considered incorporated by reference herein as would be understood by a person of skill in the art.

[0185] In an embodiment, during the listening mode / state, STA 1704-2 performs CCA or energy detection on link 1718 until a switching condition is satisfied / detected. In an embodiment, while in the listening mode / state, STA 1704-2 monitors / listens and may receive frames over a first bandwidth. In an example, the first bandwidth may be equal to the bandwidth of a PPDU used / transmitted to cause STA 1704-2 to switch from the listening mode / state to the frame exchange mode / state. For example, the first bandwidth may be equal to 160 MHz, which is the bandwidth of the PPDU used / transmitted to cause STA 1704-2 to switch from the listening mode / state to the frame exchange mode / state.

[0186] In an embodiment, the switching condition is satisfied / detected for link 1718 when MLD 1704 receives, via link 1718, a control frame (e.g., ICF) of a second type. In an embodiment, the control frame (e.g., ICF) of the second type comprises a null data PPDU (NDP). For example, the NDP may be an IMMW SU NDP or an IMMW wide BW NDP asDocket No.: 25-3020PCTillustrated in FIG. 20. In an embodiment, a bandwidth of the control frame (e.g. , IGF) of the second type may be 160 MHz or 320 MHz. As an NDP is a PPDU that does not include a MAC / data portion, STA 1704-2 can receive the control frame (eg., IGF) of the second type much faster than receiving a control frame with a data / MAC portion. This allows STA 1704-2 to reduce its power consumption while in the listening mode / state, particularly when STA 1704-2 uses a large (e.g., 160 MHz or higher) listening bandwidth during the listening mode / state. In an embodiment, a signal field (e.g., U-SIG and / or IMMW-SIG) of the NDP carries the information (e.g., TXOP duration, number of spatial streams, bandwidth, etc.) typically carried in a control frame (e.g., IGF) with a data / MAC portion. In an embodiment, STA 1704-2 determines to switch from the listening mode / state to the frame exchange mode / state based on reading / decoding its own STAJD or BSS Color in a signal field of the NDP. In such an embodiment, STA 1704-2 may switch to the frame exchange mode / state without fully receiving / decoding the NDP. In an embodiment, after switching to the frame exchange mode / state, STA 1704-2 can transmit or receive frames over a second bandwidth. The second bandwidth may be equal to or greater than the first bandwidth. Additionally, after switching to the frame exchange mode / state, STA 1704-2 may transmit or receive using more than one spatial stream.

[0187] In an embodiment, the STA, affiliated with MLD 1704, operating on the link for which the switching condition is satisfied / detected switches from the listening mode / state to the frame exchange mode / state. After switching to the frame exchange mode / state, the STA affiliated with MLD 1704 on that link can transmit or receive frames on the link (subject to its spatial stream capabilities, operation mode, etc.). The STA affiliated with MLD 1704 on the other link may continue to operate in the listening mode / state. MLD 1704 may return to the listening mode / state after an end of the frame exchange on the link for which the switching condition is satisfied / detected.

[0188] Returning to example 1700, after transmitting frame 1706, MLD 1704 may enter the listening mode / state of the mode of operation on one or more of links 1716 and 1718. In example 1700, it is assumed that MLD 1704 enters the listening mode / state on at least link 1718 (60 GHz or mmWave link). Subsequently, MLD 1702 transmits a frame 1708 via link 1718 to cause MLD 1704 to transition to the frame exchange mode / state on link 1718. In an embodiment, frame 1708 may be a control frame (e.g., ICF) of the second type as described above. STA 1704-2, operating in the listening state / mode, receives frame 1708 and determines that the switching condition for link 1718 is satisfied (e.g., based on reading / decoding its own STAJ D or BSS Color in a signal field of frame 1708 as described above). As such, as shown in FIG. 17, STA 1704-2 switches from the listening mode / state to the frame exchange mode / state.

[0189] In an embodiment, after switching to the frame exchange state / mode on link 1718, MLD 1704 may transmit a frame (e.g., ICR) 1710 to MLD 1702 via link 1718. In an embodiment, MLD 1704 may transmit frame 1710 a SIFS after receiving frame 1708. Subsequently, MLDs 1702 and 1704 may exchange one or more frames on link 1718. For example, MLD 1702 may transmit to MLD 1704 a frame 1712. Frame 1712 may comprise a data frame. MLD 1704 may respond to frame 1712 by transmitting a frame 1714 to MLD 1702. Frame 1714 may comprise a BA frame. With MLD 1704 operating in the frame exchange state / mode on link 1718, PPDUs carrying frame 1712 and / or 1714 may have a larger bandwidth and / or may comprise more than one spatial stream.Docket No.: 25-3020PCT

[0190] FIG. 18 illustrates an example 1800 of a further example operation according to an embodiment. As shown in FIG. 18, example 1800 includes an MLD 1802 and an MLD 1804. MLD 1802 may include an AP MLDoranon-AP MLD. MLD 1804 may include an AP MLDora non-AP MLD. In an example, MLD 1802 include a STA 1802-1 anda STA 1802-2. STAs 1802-1 and 1802-2 are AP STAs when MLD 1802 is an AP MLD, and non-AP STAs when MLD 1802 is a non-AP MLD. In an example, MLD 1804 include a STA 1804-1 and a STA 1804-2. STAs 1804-1 and 1804-2 are AP STAs when MLD 1804 is an AP MLD, and non-AP STAs when MLD 1804 is a non-AP MLD. In example 1800, STA 1802-1 and STA 1804-1 operate on a link 1816, and STA 1802-2 and STA 1804-2 operate on a link 1818.

[0191] In example 1800, link 1816 Isa sub-7 GHz (2.4 GHz, 5 GHz, or 6 GHz) link. As such, a carrierfrequency of link 1816 (or of channel(s) of / within link 1816) fall within a sub-7 GHz band (2.5 GHz, 6 GHz, or 6 GHz band). Link 1818 is a 60 GHz or millimeter wave (mmWave) link. As such, a carrier frequency of link 1818 (or of channel(s) of / within link 1818) fall within a 60 GHz or mmWave band (e.g. , between 42 GHz and 71 GHz). STAs 1802-2 and 1804-2 operating on link 1818 may be referred to as IMMW STAs. Embodiments however are not limited by this example.

[0192] Example 1800 begins with MLD 1804 transmitting a frame 1806. In an example, MLD 1804 may transmit frame 1806, via STA 1804-1, on link 1816. In another example, MLD 1804 may transmit frame 1806, via STA 1804-2, on link 1818. In an embodiment, frame 1806 indicates activation of a mode of operation at MLD 1804. In an embodiment, the mode of operation comprises EMLSR operation, EMLMR operation, and / or a PS mode (e.g., DPS or SMPS) as described above. As described above, in EMLSR operation, MLD 1804 operates in a listening mode / state on links 1816 and 1818 and switches to a frame exchange mode / state on one of links 1816 and 1818 when a switching condition is satisfied / detected. As described above, when the PS mode is activated for link 1816 (1818), STA 1804-1 (1804-2), affiliated with MLD 1804 on link 1816 (1818), operates in an LC mode / state during a listening mode / state of the PS mode and in an HC mode / state during a frame exchange / state mode of the PS mode. STA 1804-1 (1804-2) switches from the LC mode / state to the HC mode / state when a switching condition is detected.

[0193] In an embodiment, STA 1804-1 performs similar operations in the listening state / mode of the mode of operation (e.g., EMLSR, EMLMR, PS mode) as described above with respect to STA 1604-1 and switches from the listening mode / state to the frame exchange mode / state for the same switching conditions described above with respect to STA 1604-1. In an embodiment, STA 1804-1 perform similar operations in the frame exchange mode / state of the mode of operation (e.g., EMLSR, EMLMR, PS mode) as described above with respect to STA 1604-1. For the sake of brevity, the description of these operations is not repeated herein and is considered incorporated by reference herein as would be understood by a person of skill in the art.

[0194] In an embodiment, during the listening mode / state, STA 1804-2 performs CCA or energy detection on link 1818 until a switching condition is satisfied / detected. In an embodiment, while in the listening mode / state, STA 1804-2 monitors / listens to and may receive frames over a first bandwidth. In an example, the first bandwidth may be narrower than the bandwidth of a PPDU used / transmitted to cause STA 1804-2 to switch from the listening mode / state to the frame exchange mode / state. For example, the first bandwidth may be equal to 20 MHz, whereas the bandwidth of the PPDU used / transmitted to cause STA 1804-2 to switch from the listening mode / state to the frame exchange mode / state may beDocket No.: 25-3020PCTequal to 40 MHz, 80 MHz, or 160 MHz. In another example, the first bandwidth may be equal to 40 MHz, whereas the bandwidth of the PPDU used / transmitted to cause STA 1804-2 to switch from the listening mode / state to the frame exchange mode / state may be equal to 80 MHz or 160 MHz, for example. In another example, the first bandwidth may be equal to 80 MHz, whereas the bandwidth of the PPDU used / transmitted to cause STA 1804-2 to switch from the listening mode / state to the frame exchange mode / state may be equal to 160 MHz, for example. In an embodiment, the PPDU used / transmitted to cause STA 1804-2 to switch from the listening mode / state to the frame exchange mode / state comprises multiple 20 MHz PPDUs duplicated over multiple 20 MHz channels (e.g., to meet a minimum IMMW transmission bandwidth on link 1818). A combined bandwidth of the multiple 20 MHz channels maybe equal to 40 MHz (two 20 MHz channels), 80 MHz (four 20 MHz channels), or 160 MHz (or eight 20 MHz channels), for example. The first bandwidth used / monitored by STA 1804-2 during the listening mode / state may be a portion of the combined bandwidth of the multiple 20 MHz channels. This allows STA 1804-2 to reduce its power consumption while in the listening mode / state.

[0195] In an embodiment, the switching condition is satisfied / detected for link 1818 when MLD 1804 receives, via link 1818, a control frame (e.g., ICF) of a third type. In an embodiment, the control frame of the third type may comprise an existing sub-7 GHz frame, such as an RTS frame or a trigger frame similar to trigger frame 1900 described further below in FIG. 19. In an embodiment, the control frame of the third type is carried in a 20 MHz PPDU. STA 1804-2 receives the control frame of the third type over the first bandwidth (e.g., 20 MHz) that STA 1804-2 monitors / listens to during the listening mode / state. In an embodiment, the 20 MHz PPDU comprises a non-high throughput (non-HT) PPDU, a high throughput (HT) PPDU, a very high throughput (VHT) PPDU, a high efficiency (HE) PPDU, an extremely high throughput (EHT) PPDU, an ultra-high reliability (UHR) PPDU, or an integrated millimeter wave (IMMW) PPDU. In an embodiment, STA 1804-2 determines to switch from the listening mode / state to the frame exchange mode / state based on reading / decoding its own STAJ D or BSS Color in the control frame of the third type. In an embodiment, after switching to the frame exchange mode / state, STA 1804-2 can transmit or receive frames over a second bandwidth. The second bandwidth may be equal to or greater than the first bandwidth. In an embodiment, in addition to STA 1804-2 monitoring / listening for a 20 MHz control frame during the listening mode / state, STA 1804-2 may also monitor / listen for a control frame transmitted using the second bandwidth in a parallel manner. Additionally, after switching to the frame exchange mode / state, STA 1804-2 may transmit or receive using more than one spatial stream.

[0196] In an embodiment, the STA, affiliated with MLD 1804, operating on the link for which the switching condition is satisfied / detected switches from the listening mode / state to the frame exchange mode / state. After switching to the frame exchange mode / state, the STA affiliated with MLD 1804 on that link can transmit or receive frames on the link (subject to its spatial stream capabilities, operation mode, etc.). The STA affiliated with MLD 1804 on the other link may continue to operate in the listening mode / state. MLD 1804 may return to the listening mode / state after an end of the frame exchange on the link for which the switching condition is satisfied / detected.

[0197] Returning to example 1800, after transmitting frame 1806, MLD 1804 may enter the listening mode / state of the mode of operation on one or more of links 1816 and 1818. In example 1800, it is assumed that MLD 1804 enters theDocket No.: 25-3020PCTlistening mode / state on at least link 1818 (60 GHz or mmWave link). Subsequently, MLD 1802 transmits a PPDU 1820 via link 1818 to cause MLD 1804 to transition to the frame exchange mode / state on link 1818. PPDU 1820 may be a duplicate mode PPDU. As shown, PPDU 1820 comprises a PPDU 1808 duplicated over multiple adjacent channels of link 1818. In an embodiment, PPDU 1808 may be a 20 MHz PPDU. In an embodiment, the 20 MHz PPDU comprises a non-HT PPDU (as illustrated in FIG. 12), an EHT PPDU, a UHR PPDU, ora 20 MHz IMMW PPDU. In example 1800, PPDU 1820 comprises PPDU 1808 duplicated four times for a total bandwidth of 80 MHz for PPDU 1820. PPDU 1808 carries a control frame (e.g., IGF) of the third type as described above.

[0198] STA 1804-2, operating in the listening state / mode on the first bandwidth described above, receives PPDU 1808 and determines that the switching condition for link 1818 is satisfied (e.g., based on reading / decoding its own STAJ D or BSS Color in the frame contained therein). As such, as shown in FIG. 18, STA 1804-2 switches from the listening mode / state to the frame exchange mode / state.

[0199] In another embodiment, MLD 1802 transmits a control / activation frame (e.g , ICF) via link 1816 (not shown in FIG. 18) to cause MLD 1804 to transition to the frame exchange mode / state on link 1818. In an embodiment, the control / activation frame may include any management frame (e.g., action frame) or any data frame (e.g., QoS null frame). In an embodiment, the switching condition is satisfied / detected for link 1818 when MLD 1804 receives, via link 1816, the control / activation frame (e.g., ICF). In an embodiment, the control frame sets up a schedule for exchanging frame(s) between MLDs 1802 and 1804. In an embodiment, the schedule may include a service period between MLDs 1802 and 1804 for exchanging frames. In an embodiment, the service period may include a target wake time service period or restricted target wake time service period. In an embodiment, the schedule may be on-demand or periodic. In an embodiment, STA 1804-2 switches from the listening mode / state to the frame exchange mode / state based on the schedule. In an embodiment, the schedule may start a time offset after the transmission of the control / activation frame. In an embodiment, the time offset may include an activation delay of MLD 1804 and / or MLD 1802. In an embodiment, STA 1804-2 switches from the listening mode / state to the frame exchange mode / state based on STA 1804-1 reading / decoding the control frame. In an embodiment, after switching to the frame exchange mode / state, STA 1804-2 can transmit or receive frames up to a second bandwidth over which STA 1804-2 is capable of operating. The second bandwidth maybe equal to or greater than the first bandwidth. In an embodiment, the control frame received via link 1816 may indicate one or more links in which MLD 1802 is initiating transmission. In an embodiment, based on the indication of the one or more links, MLD 1804 switches STA 1804-1 and / or STA 1804-2 to the frame exchange mode / state. In an embodiment, in addition to STA 1804-1 monitoring / listening for a 20 MHz control frame during the listening mode / state, STA 1804-2 may also monitor / listen for a control frame transmitted using the second bandwidth in a parallel manner. Additionally, after switching to the frame exchange mode / state, STA 1804-1 and / or STA 1804-2 may transmit or receive using more than one spatial stream.

[0200] In an embodiment, the STA, affiliated with MLD 1804, operating on the one or more links for which the switching condition is satisfied / detected switches from the listening mode / state to the frame exchange mode / state. After switching to the frame exchange mode / state, the STAs affiliated with MLD 1804 on the one or more links can transmit or receiveDocket No.: 25-3020PCTframes on their corresponding links (subject to its spatial stream capabilities, operation mode, etc.). The STAs affiliated with MLD 1804 on the other links (i.e. links that do not belong to the one or more links) may continue to operate in the listening mode / state. MLD 1804 may return to the listening mode / state after an end of the frame exchange on the link for which the switching condition is satisfied / detected.

[0201] In an embodiment, after switching to the frame exchange state / mode on link 1818, MLD 1804 may transmit a frame (e.g., ICR) 1810 to MLD 1802 via link 1818. In an embodiment, MLD 1804 may transmit frame 1810 a SIFS after receiving PPDU 1808. Subsequently, MLDs 1802 and 1804 may exchange one or more frames on link 1818. For example, MLD 1802 may transmit to MLD 1804 a frame 1812. Frame 1812 may comprise a data frame. MLD 1804 may respond to frame 1812 by transmitting a frame 1814 to MLD 1802. Frame 1814 may comprise a BA frame. With MLD 1804 operating in the frame exchange state / mode on link 1818, PPDUs carrying frame 1812 and / or 1814 may have a larger bandwidth and / or may comprise more than one spatial stream.

[0202] FIG. 19 illustrates an example trigger frame 1900. As described above, trigger frame 1900 may be used for the control frame of the first type used in the embodiment illustrated in FIG. 16 or for the control frame of the third type used in the embodiment illustrated in FIG. 18. When used for the control frame of the first type, trigger frame 1900 may be carried in IMMWSU PPDU as illustrated in FIG. 13 above. When used for the control frame of the third type, trigger frame 1900 may be carried in a 20 MHz PPDU. The 20 MHz PPDU comprises a non-HT PPDU (as illustrated in FIG. 12), an HT PPDU, a VHT PPDU, an HE PPDU, an EHT PPDU, a UHR PPDU, or an IMMW PPDU. In an example, trigger frame 1900 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 1900 may also carry other information required by a responding STA to transmit a TB PPDU to the AP.

[0203] As shown in FIG. 19, trigger frame 1900 includes a Frame Control field, a Duration field, a receiver address (RA) field, a transmitter address (TA) field, a Common Info field, a User Info List field, a Padding field, and an FCS field.

[0204] 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.

[0205] 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).

[0206] 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 1900 if trigger frame 1900 is addressed to STAs that belong to a single BSS. The TA field is the transmitted BSSID if trigger frame 1900 is addressed to STAs from at least two different BSSs of the multiple BSSID set.

[0207] The Common Info field specifies a trigger frame type of trigger frame 1900, a transmit power of trigger frame 1900 in dBm, and several key parameters of a TB PPDU that is transmitted by a STA in response to trigger frame 1900.Docket No.: 25-3020PCTThe 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. A non-EHT non-AP HE STA interprets the Common Info field as HE variant. A non-AP EHT STA interprets the Common Info field as HE variant if B54 and B55 in the Common Info field are equal to 1; and interprets the Common Info field as EHT variant otherwise. The HE variant Common Info field and the EHT variant Common Info field use the same encoding method for the Trigger Type, UL Length, More TF, CS Required, LDPC Extra Symbol Segment, AP TX Power, Pre-FEC Padding Factor, PE Disambiguity, and Trigger Dependent Common Info subfields.

[0208] The User Info List field contains zero or more User Info fields. There are three variants for the User Info field, which are the Special User Info field, the EHT variant User Info field, and the HE variant User Info field.

[0209] The Special User Info field is a User Info field that does not carry the user specific information but carries the extended common information not provided in the Common Info field. If the Special User Info field is included in the Trigger frame, then the Special User Info Field Flag subfield of the EHT variant Common Info field is set to 0, otherwise it is set to 1. The Special User Info field is identified by an AID12 value of 2007 and is optionally present in a Trigger frame that is generated by an EHT AP. The Special User Info field, if present, is located immediately after the Common Info field of the Trigger frame and carries information for the U-SIG field of a solicited EHT TB PPDU. The PHY Version Identifier subfield indicates the PHY version of the solicited TB PPDU that is not an HE TB PPDU. The PHY Version Identifier subfield is set to 0 for EHT. Other values from 1 to 7 are reserved. The UL Bandwidth (BW) Extension subfield, together with the UL BW subfield in the Common Info field, indicates the bandwidth of the solicited TB PPDU from the addressed EHT STA (i.e., the bandwidth in the U-SIG field of the EHT TB PPDU). The EHT Spatial Reuse n subfield carries the values to be included in the corresponding Spatial Reuse n subfield in the U-SIG field of the EHT TB PPDU. The U-SIG Disregard And Validate subfield carries the values to be included in the Disregard and Validate subfields of the U-SIG field of the solicited EHT TB PPDUs. The presence and length of the Trigger Dependent User Info subfield in the Special User Info field depends on the variant of the Trigger frame.

[0210] The EHT variant User Info field contains a User Info field per STA addressed in trigger frame 1900. The per STA User Info field includes, among others, an Al D12 subfield, an RU Allocation subfield, a UL FEC Coding Type subfield, a UL EHT-MCS subfield, a Reserved subfield, a Spatial Stream (SS) Allocation / RA-RU information subfield, a UL Target Receive Power subfield, and a Power Save (PS) 160 subfield to be used by a STA in a TB PPDU transmitted in response to trigger frame 1900, and a Trigger Dependent User Info subfield. The RU Allocation subfield in an EHT variant User Info field in a Trigger frame that is not an MU-RTS Trigger frame, along with the UL BW subfield in the Common Info field, the UL BW Extension subfield in the Special User Info field, and the PS160 subfield in the EHT variant User Info field, identifies the size and the location of the RU or MRU. The values of PS160 subfield and B0 of RU Allocation subfield indicate the 80 MHz frequency subblock in which the RU or MRU is located for 26-tone RU, 52-tone RU, 106-tone RU, 242-tone RU, 484-tone RU, 996-tone RU, 52+26-tone RU, and 106+26-tone RU. The values of PS160 subfield indicates the 160 MHz segment in which the RU or MRU is located for 2x996-tone RU, 996+484-tone MRU, and 996+484+242-tone MRU. The UL FEC Coding Type subfield of the User Info field indicates the code type of the solicited EHT TB PPDU. The UL FEC Coding Type subfield is set to 0 to indicate BCC and set to 1 to indicate LDPC. The UL EHT-MCS subfieldDocket No.: 25-3020PCTof the User Info field indicates the EHT-MCS of the solicited EHTTB PPDU. TheSS Allocation subfield of the EHT variant User Info field indicates the spatial streams of the solicited EHT TB PPDU. The UL Target Receive Power subfield indicates the expected receive signal power, measured at the AP's antenna connector and averaged over the antennas, for the EHT portion of the EHT TB PPDU transmitted on the assigned RU. 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. The RA-RU Information subfield is reserved in the EHT variant User Info field.

[0211] The Padding field is optionally present in frame 1900 to extend the frame length to give recipient STAs enough time to prepare a response for transmission one SIPS after the frame is received. The Padding field, if present, is at least two octets in length and is set to all 1s. 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.

[0212] FIG. 20 illustrates example null data PPDU (NDPs) which may be used in embodiments. Specifically, FIG. 20 illustrates an IMMW SU NDP 2002 and an IMMW Wide Bandwidth (BW) NDP 2004. As described above, IMMW SU NDP 2002 or IMMW Wide BW NDP 2004 may be used for the control frame of the second type illustrated in FIG. 18 above. Additionally, in an embodiment, IMMW SU NDP 2002 or IMMW Wide BW NDP 2004 may be used for frame 1608 described in FIG. 16.

[0213] As shown in FIG.20, IMMW SU NDP 2002 may include an L-STF, an L-LTF, a U-SIG, an IMMW-SIG, an IMMW-STF, one or more IMMW-LTF, and a PE. The IMMW-SIG, the IMMW-STF, and the IMMW-LTF may be similar to the corresponding fields of IMMW SU PPDU 1304 described in FIG. 13 above. In IMMW Wide BW NDP 2004, the L-STF, L-LTF, U-SIG, and IMMW-SIG of IMMW SU NDP 2002 are duplicated one or more times in frequency up to the bandwidth of IMMW Wide BW NDP 2004. The IMMW-STF, the IMMW-LTF, and the PE use a wider tone plan that covers the bandwidth of IMMW Wide BW NDP 2004.

[0214] 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 of embodiments. Example process 2100 may be performed by a first MLD, such as MLD 1604, MLD 1704, and MLD 1804. The first MLD supports a mode of operation, which includes a listening mode / state and a frame exchange mode / state. The mode of operation may include ELMSR, ELMMR, or a PS mode (e.g., DPS or SMPS), for example.

[0215] As shown in FIG. 21, process 2100 includes, in a step 2102, switching, by the first MLD, from the listening mode / state to the frame exchange mode / state of a mode of operation In an embodiment, the switching from the listening mode / state to the frame exchange mode / state is based on a received signal strength of a signal, received by the first MLD via a first link of a plurality of links, exceeding a threshold. In an embodiment, the first link is a sub-7 GHz link. In another embodiment, the first link is a mmWave link. In an embodiment, the threshold comprises a clear channel assessment energy detect threshold. In an embodiment, the threshold comprises a value between -82dBm and -62 dBm.Docket No.: 25-3020PCT

[0216] In an embodiment, process 2100 may further comprise transmitting, by the first MLD to a second MLD, a first frame activating the mode of operation.

[0217] In an embodiment, process 2100 may further comprise comprising listening, by the first MLD, on the plurality of links before the switching.

[0218] In an embodiment, process 2100 may further comprise receiving, by the first MLD from the second MLD and via the first link, a second frame comprising more than one spatial stream. In an embodiment, the receiving of the second frame comprises receiving the second frame after switching to the frame exchange mode / state.

[0219] In an embodiment, in the mode of operation, the first MLD operates in the listening mode / state on the plurality of links before switching to the frame exchange mode / state on a link of the plurality of links. In an embodiment, operating in the listening mode / state comprises performing energy detection on the plurality of links.

[0220] In an embodiment, based on the first link being a sub-7 GHz link, operating in the listening mode / state further comprises receiving, via the first link, an initial control frame (IGF) of a first type. In an embodiment, the IGF of the first type is carried in a non-HTT PPDU or a non-HT duplicate PPDU. In an embodiment, a rate of the non-HT PPDU or the non-HT duplicate PPDU is 6 Mb / s, 12 Mb / s, or 24 Mb / s. In an embodiment, the switching from the listening mode / state to the frame exchange mode / state, in step 2102, is further based on receiving the IGF of the first type.

[0221] In an embodiment, based on the first link being a mmWave link, operating in the listening mode / state further comprises receiving, via the first link, an IGF of a second type. In an embodiment, the IGF of the second type comprises a null data PPDU (NDP). In an embodiment, the switching from the listening mode / state to the frame exchange mode / state, in step 2102, is further based on receiving the ICF of the second type.

[0222] In an embodiment, based on the first link being a mmWave link, operating in the listening mode / state further comprises receiving, via the first link, an ICF of a third type. In an embodiment, the ICF of the third type is carried in a 20 MHz PPDU. In an embodiment, the 20 MHz PPDU comprises a non-HT PPDU, an HT PPDU, a VHT PPDU, an HE PPDU, an EHT PPDU, a UHR PPDU, or an IMMW PPDU. In an embodiment, the 20 MHz PPDU is duplicated over multiple 20 MHz channels ofthe first link. In an embodiment, a bandwidth of the multiple 20 MHz channels comprises 40 MHz, 80 MHz, or 160 MHz.

[0223] In an embodiment, the mode of operation comprises the PS mode. In an embodiment, in the PS mode, a first STA, affiliated with the first MLD and operating on the first link, operates in a lower capability (LG) mode during the listening mode / state of the mode of operation and in a higher capability (HC) mode during the frame exchange mode / state of the mode of operation. The first STA may comprise a mmWave STA or a sub-7 GHz STA.

[0224] In an embodiment, a first bandwidth of the listening mode / state is less than or equal to a second bandwidth of the frame exchange mode / state. In an embodiment, the first bandwidth comprises 20 MHz, 40 MHz, or 80 MHz. In an embodiment, the second bandwidth comprises 80 MHz, 160 MHz, or 320 MHz. In an embodiment, the second bandwidth comprises at least one of: a minimum bandwidth of an integrated millimeter wave (IMMW) PPDU; or a bandwidth of a signal field of an integrated millimeter wave (IMMW) PPDU.Docket No.: 25-3020PCT

[0225] In an embodiment, the mode of operation comprises an IMMW operation. In an embodiment, the switching to the frame exchange mode / state, step 2102, is further based on the first link being a mmWave link. In an embodiment, a carrier frequency of a channel of the mmWave link is between 42 GHz and 71 GHz. In an embodiment, switching, by the first MLD, from the listening mode / state to the frame exchange mode / state, in step 2102, comprises switching, by a first STA, affiliated with the first MLD and operating on the first link, from the listening mode / state to the frame exchange mode / state.

[0226] FIG. 22 illustrates another example process 2200 according to an embodiment. Example process 2200 is provided for the purpose of illustration only and is not limiting of embodiments. Example process 2200 may be performed by an AP MLD. The AP may be an embodiment of MLD 1602, MLD 1702, or MLD 1802. As shown in FIG. 22, example process 2200 may include steps 2202 and 2204.

[0227] Step 2202 includes receiving, by the AP MLD from a non-AP MLD, a first frame indicating activation of a mode of operation at the non-AP MLD. In an embodiment, the mode of operation includes a listening mode / state and a frame exchange mode / state. The mode of operation may include ELMSR, ELMMR, or a PS mode (e.g., DPS or SMPS), for example. In an embodiment, in the mode of operation, the non-AP MLD operates in the listening mode / state on a plurality of links before switching to the frame exchange mode / state on a link of the plurality of links.

[0228] Step 2204 includes transmitting, by the AP MLD to the non-AP MLD and via a first link of the plurality of links, an initial control frame (IGF) to cause the non-AP MLD to switch from the listening mode / state to the frame exchange mode / state. In an embodiment, a frame type of the IGF is based on a carrier frequency of the first link.

[0229] In an embodiment, the ICF is of a first type based on the carrier frequency of the first link falling within a sub-7 GHz band. In an embodiment, the ICF of the first type is carried in a non-HT PPDU or a non-HT duplicate PPDU. In an embodiment, a rate of the non-HT PPDU or the non-HT duplicate PPDU is 6 Mb / s, 12 Mb / s, or 24 Mb / s.

[0230] In an embodiment, the ICF is of a second type based on the carrier frequency of the first link falling within a 60 GHz band. In an embodiment, the ICF of the second type comprises a null data PPDU (NDP).

[0231] In another embodiment, the ICF is of a third type based on the carrier frequency of the first link falling within a 60 GHz band. In an embodiment, the ICF of the third type is carried in a 20 MHz PPDU. The 20 MHz PPDU may comprise a non-HT PPDU, an HT PPDU, a VHT PPDU, an HE PPDU, an EHT PPDU, a UHR PPDU, or an IMMW PPDU. In an embodiment, transmitting the ICF, in step 2202, comprises transmitting the 20 MHz PPDU duplicated over multiple 20 MHz channels of the first link. In an embodiment, a bandwidth of the multiple 20 MHz channels comprises 40 MHz, 80 MHz, or 160 MHz.

[0232] In an embodiment, process 2200 may further comprise transmitting, by the AP MLD to the non-AP MLD and via the first link, a second frame comprising more than one spatial stream. In an embodiment, the transmitting of the second frame comprises transmitting the second frame after transmitting the ICF.

[0233] In an embodiment, the mode of operation comprises the PS mode. In an embodiment, in the PS mode, a first STA, affiliated with the non-AP MLD and operating on the first link, operates in a lower capability (LC) mode during theDocket No.: 25-3020PCTlistening mode / state of the mode of operation and in a higher capability (HC) mode during the frame exchange mode / state of the mode of operation. The first STA may comprise a mmWave STA or a sub-7 GHz STA.

[0234] In an embodiment, a first bandwidth of the listening mode / state is less than or equal to a second bandwidth of the frame exchange mode / state. In an embodiment, the first bandwidth comprises 20 MHz, 40 MHz, or 80 MHz. In an embodiment, the second bandwidth comprises 80 MHz, 160 MHz, or 320 MHz. In an embodiment, the second bandwidth comprises at least one of: a minimum bandwidth of an integrated millimeter wave (IMMW) PPDU; or a bandwidth of a signal field of an integrated millimeter wave (IMMW) PPDU.

[0235] In an embodiment, the mode of operation comprises an integrated millimeter wave (IMMW) operation (operation over at least one mmWave link). In an embodiment, the transmitting of the ICF, in step 2202, with the frame type of the ICF based on the carrier frequency of the first link is based on the mode of operation comprising IMMW operation.

Claims

Docket No.: 25-3020PCTCLAIMSWhat is claimed is:

1. A method comprising:transmitting, by a non-access point (non-AP) multi-link device (MLD) to an AP MLD, a first frame indicating activation of an enhanced multi-link single radio (EMLSR) mode of operation at the non-AP MLD, wherein, in the EMLSR mode of operation, the non-AP MLD operates in a listening mode / state on a plurality of links before switching to a frame exchange mode / state on a link of the plurality of links;listening, by the non-AP MLD, on the plurality of links;based on a received signal strength, of a signal received via a first link of the plurality of links, exceeding a threshold, switching, by the non-AP MLD, from the listening mode / state to the frame exchange mode / state on the first link; andafter switching to the frame exchange mode / state, receiving, by the non-AP MLD from the AP MLD and via the first link, a second frame comprising more than one spatial stream.

2. A method comprising:based on a received signal strength of a signal, received by a first multi-link device (MLD) via a first link of a plurality of links, exceeding a threshold, switching, by the first MLD, from a listening mode / state to a frame exchange mode / state of a mode of operation.

3. The method of claim 2, further comprising transmitting, by the first MLD to a second MLD, a first frame indicating activation of the mode of operation at the first MLD.

4. The method of any of claims 2-3, further comprising listening, by the first MLD, on the plurality of links before the switching.

5. The method of any of claims 3-4, further comprising receiving, by the first MLD from the second MLD and via the first link, a second frame comprising more than one spatial stream.

6. The method of claim 5, wherein the receiving of the second frame comprises receiving the second frame after switching to the frame exchange mode / state.

7. The method of any of claims 2-6, wherein, in the mode of operation, the first MLD operates in the listening mode / state on the plurality of links before switching to the frame exchange mode / state on a link of the plurality of links.

8. The method of claim 7, wherein operating in the listening mode / state comprises performing energy detection on the plurality of links.

9. The method of claim 8, wherein, based on the first link being a sub-7 GHz link, operating in the listening mode / state further comprises receiving, via the first link, an initial control frame (ICF) of a first type.

10. The method of claim 9, wherein the ICF of the first type is carried in a non-high throughput (HT) physical layer protocol data unit (PPDU) or a non-HT duplicate PPDU.Docket No.: 25-3020PCT11. The method of claim 10, wherein a rate of the non-HT PPDU or the non-HT duplicate PPDU is 6 Mb / s, 12 Mb / s, or 24 Mb / s.

12. The method of any of claims 9-11, wherein the switching from the listening mode / state to the frame exchange mode / state is further based on receiving the ICF of the first type.

13. The method of claim 8, wherein, based on the first link being a millimeter wave (mmWave) link, operating in the listening mode / state further comprises receiving, via the first link, an ICF of a second type.

14. The method of claim 13, wherein the ICF of the second type comprises a null data PPDU (NDP).

15. The method of any of claims 13-14, wherein the switching from the listening mode / state to the frame exchange mode / state is further based on receiving the ICF of the second type.

16. The method of claim 8, wherein, based on the first link being a millimeter wave (mmWave) link, operating in the listening mode / state further comprises receiving, via the first link, an ICF of a third type.

17. The method of claim 16, wherein the ICF of the third type is carried in a 20 MHz physical layer protocol data unit (PPDU).

18. The method of claim 17, wherein the 20 MHz PPDU comprises a non-high throughput (non-HT) PPDU, a high throughput (HT) PPDU, a very high throughput (VHT) PPDU, a high efficiency (HE) PPDU, an extremely high throughput (EHT) PPDU, an ultra-high reliability (UHR) PPDU, or an integrated millimeter wave (IMMW) PPDU.

19. The method of any of claims 17-18, wherein the 20 MHz PPDU is duplicated over multiple 20 MHz channels of the first link.

20. The method of claim 19, wherein a bandwidth of the multiple 20 MHz channels comprises 40 MHz, 80 MHz, or 160 MHz.

21. The method of any of claims 2-20, wherein the mode of operation comprises:an enhanced multi-link single-radio (EMLSR) operation; oran enhanced multi-link multiple-radio (EMLMR) operation.

22. The method of claim 2, wherein the mode of operation comprises a power save (PS) mode.

23. The method of claim 22, wherein the PS mode comprises a dynamic power save (DPS) mode or spatial multiplexing power save (SMPS) mode.

24. The method of any of claims 22-23, wherein, in the PS mode, a first station (STA), affiliated with the first MLD and operating on the first link, operates in a lower capability (LC) mode during the listening mode / state of the mode of operation and in a higher capability (HC) mode during the frame exchange mode / state of the mode of operation.

25. The method of claim 24, wherein the first STA comprises a millimeter wave (mmWave) STA or a sub-7 GHz STA.

26. The method of any of claims 2-25, wherein a first bandwidth of the listening mode / state is less than or equal to a second bandwidth of the frame exchange mode / state.

27. The method of claim 26, wherein the first bandwidth comprises 20 MHz, 40 MHz, or 80 MHz.

28. The method of any of claims 26-27, wherein the second bandwidth comprises 80 MHz, 160 MHz, or 320 MHz.

29. The method of any of claims 26-28, wherein the second bandwidth comprises at least one of:Docket No.: 25-3020PCTa minimum bandwidth of an integrated millimeter wave (IMMW) PPDU; ora bandwidth of a signal field of an integrated millimeter wave (IMMW) PPDU.

30. The method of any of claims 2-29, wherein the threshold comprises a clear channel assessment energy detect threshold.

31. The method of any of claims 2-30, wherein the threshold comprises a value between -82dBm and -62 dBm.

32. The method of any of claims 2-31 , wherein the switching to the frame exchange mode / state is further based on the first link being a millimeter wave (mmWave) link.

33. The method of claim 32, wherein a carrier frequency of a channel of the mmWave link is between 42 GHz and 1 GHz.

34. The method of any of claims 2-33, wherein the mode of operation comprises an integrated millimeter wave (IMMW) operation.

35. The method of any of claims 2-34, wherein switching, by the first MLD, from the listening mode / state to the frame exchange mode / state of the mode of operation comprises switching, by a first station (STA), affiliated with the first MLD and operating on the first link, from the listening mode / state to the frame exchange mode / state.

36. A method comprising:receiving, by an access point (AP) multi-link device (MLD) from a non-AP MLD, a first frame indicating activation of an enhanced multi-link single radio (EMLSR) mode of operation at the non-AP MLD, wherein, in the EMLSR mode of operation, the non-AP MLD operates in a listening mode / state on a plurality of links before switching to a frame exchange mode / state on a link of the plurality of links; andtransmitting, by the AP MLD to the non-AP MLD and via a first link of the plurality of links, an initial control frame (IGF) to cause the non-AP MLD to switch from the listening mode / state to the frame exchange mode / state,wherein, based on the first link being a millimeter wave (mmWave) link, the IGF comprises a null data physical layer protocol data unit (NDP).

37. A method comprising:receiving, by an access point (AP) multi-link device (MLD) from a non-AP MLD, a first frame indicating activation of a mode of operation at the non-AP MLD, wherein, in the mode of operation, the non-AP MLD operates in a listening mode / state on a plurality of links before switching to a frame exchange mode / state on a link of the plurality of links; andtransmitting, by the AP MLD to the non-AP MLD and via a first link of the plurality of links, an initial control frame (ICF) to cause the non-AP MLD to switch from the listening mode / state to the frame exchange mode / state, wherein a frame type of the ICF is based on a carrier frequency of the first link.

38. The method of claim 37, further comprising transmitting, by the AP MLD to the non-AP MLD and via the first link, a second frame comprising more than one spatial stream.Docket No.: 25-3020PCT39. The method of claim 38, wherein the transmitting of the second frame comprises transmitting the second frame after transmitting the IGF.

40. The method of any claims 37-39, wherein the ICF is of a first type based on the carrier frequency of the first link falling within a sub-7 GHz band.

41. The method of claim 40, wherein the ICF of the first type is carried in a non-high throughput (HT) physical layer protocol data unit (PPDU) or a non-HT duplicate PPDU.

42. The method of claim 41 , wherein a rate of the non-HT PPDU or the non-HT duplicate PPDU is 6 Mb / s, 12 Mb / s, or 24 Mb / s.

43. The method of any of claims 37-39, wherein the ICF is of a second type based on the carrier frequency of the first link falling within a 60 GHz band.

44. The method of claim 43, wherein the ICF of the second type comprises a null data PPDU (NDP).

45. The method of any of claims 37-39, wherein the ICF is of a third type based on the carrier frequency of the first link falling within a 60 GHz band.

46. The method of claim 45, wherein the ICF of the third type is carried in a 20 MHz physical layer protocol data unit (PPDU).

47. The method of claim 46, wherein the 20 MHz PPDU comprises a non-high throughput (non-HT) PPDU, a high throughput (HT) PPDU, a very high throughput (VHT) PPDU, a high efficiency (HE) PPDU, an extremely high throughput (EHT) PPDU, an ultra-high reliability (UHR) PPDU, or an integrated millimeter wave (IMMW) PPDU.

48. The method of any of claims 46-47, wherein transmitting the ICF comprises transmitting the 20 MHz PPDU duplicated over multiple 20 MHz channels of the first link.

49. The method of claim 48, wherein a bandwidth of the multiple 20 MHz channels comprises 40 MHz, 80 MHz, or 160 MHz.

50. The method of any of claims 37-49, wherein the mode of operation comprises:an enhanced multi-link single-radio (EMLSR) operation; oran enhanced multi-link multiple-radio (EMLMR) operation.

51. The method of claim 37, wherein the mode of operation comprises a power save (PS) mode.

52. The method of claim 51 , wherein the PS mode comprises a dynamic power save (DPS) mode or spatial multiplexing power save (SMPS) mode.

53. The method of any of claims 51-52, wherein, in the PS mode, a first station (STA), affiliated with the non-AP MLD and operating on the first link, operates in a lower capability (LC) mode during the listening mode / state of the mode of operation and in a higher capability (HC) mode during the frame exchange mode / state of the mode of operation.

54. The method of claim 53, wherein the first STA comprises a millimeter wave (mmWave) STA or a sub-7 GHz STA.

55. The method of any of claims 37-54, wherein a first bandwidth of the listening mode / state is less than or equal to a second bandwidth of the frame exchange mode / state.Docket No.: 25-3020PCT56. The method of claim 55, wherein the first bandwidth comprises 20 MHz, 40 MHz, or 80 MHz.

57. The method of any of claims 55-56, wherein the second bandwidth comprises 80 MHz, 160 MHz, or 320 MHz.

58. The method of any of claims 55-57, wherein the second bandwidth comprises at least one of:a minimum bandwidth of an integrated millimeter wave (IMMW) PPDU; ora bandwidth of a signal field of an integrated millimeter wave (IMMW) PPDU.

59. The method of any of claims 37-58, wherein the mode of operation comprises an integrated millimeter wave (IMMW) operation.

60. 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 1-59.

61. 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 1-59.

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