Media synchronization recovery assisted between access points

Description

1 / 89 “ASSISTED MEDIUM SYNCHRONIZATION RECOVERY BETWEEN ACCESS POINTS” FIELD

[001] The present invention relates to wireless networks, in particular, local area networks, such as those using the IEEE 802.11 standard. BACKGROUND

[002] Wireless networks are frequently subject to interference from other networks. Transmissions from these other networks can prevent the successful reception of messages sent between devices on the network in question, hindering the coordination of other transmissions on the network. As network complexity and density increase, the impact of impaired coordination is felt more strongly. SUMMARY

[003] The inventors realized that the problem is acute in networks that use so-called multi-link devices (MLDs) because the level of complexity is higher and the need for coordination between devices is increased. In a situation where both APs and STAs are MLDs, interference, for example, from another network (an OBSS in the case of 802.11) on one link can have an impact on the other link, i.e., the problem of throughput loss is aggravated.

[004] Therefore, aspects, embodiments and variants of the invention are defined in the appended claims.

[005] Thus, according to one aspect, a method is provided comprising receiving, by a first access point (AP), a first frame transmitted by a station (STA) to a second AP, comprising a request to the second AP; and, based on the first AP not receiving an acknowledgment frame from the second AP to the STA in response to the first frame, transmitting, by the first AP to the second AP, a second frame. Petition 870250094447, dated 10 / 16 / 2025, pp. 201 / 332 2 / 89

[006] The second AP is able to detect that the first AP did not hear the first frame.

[007] According to one modality, the request is an AP assistance request (AAR).

[008] According to one modality, the request is for the second link.

[009] According to one modality, the second frame is arranged to inform the second AP about the request contained in the first frame.

[010] According to one modality, receiving the first frame includes receiving the first frame through a first link or a second link.

[011] According to one embodiment, the transmission of the second frame comprises transmitting the second frame through the first link or a second link.

[012] According to one modality, the AAR requests that the second AP transmit a third frame, via the second link, to the STA.

[013] According to one embodiment, the second frame assists the STA in recovering media synchronization on the second link.

[014] According to one modality, the second frame comprises an indication of the second link.

[015] According to one modality, the second table comprises an indication of the STA.

[016] According to one embodiment, the second AP transmits a third frame, via the second link, to the STA in response to the second frame.

[017] According to one embodiment, the second frame comprises a management frame.

[018] According to one embodiment, the second frame comprises a control frame.

[019] According to one embodiment, the second frame comprises a data frame. Petition 870250094447, dated 10 / 16 / 2025, pp. 202 / 332 3 / 89

[020] There is also provided, according to one aspect, a method comprising receiving, by a first access point (AP) from a second AP, a first frame informing the first AP of a request to the first AP transmitted by a station (STA); and, based on the receipt of the first frame, transmitting, by the first AP to the STA, a second frame.

[021] According to one modality, the first frame informs the first AP over the AAR that operates on the second link.

[022] According to one modality, the AAR requests that the first AP transmit the second frame, through the second link, to the STA.

[023] According to one modality, the first frame assists the STA to recover media synchronization on the second link.

[024] According to one embodiment, the first AP transmits a second frame, through the second link, to the STA in response to the first frame.

[025] According to one aspect, a method is provided comprising transmitting, by a station (STA) to a first AP, a first frame comprising a request to the first AP; and receiving, by the STA of a second AP, a second frame in response to the first frame.

[026] According to one embodiment, the transmission of the first frame comprises transmitting the first frame through a first link.

[027] According to one modality, receiving the second frame involves receiving the second frame through a second link.

[028] According to one modality, the second frame tells the STA to transmit a fourth frame, via the second link, to the first AP.

[029] In respect of one aspect, a method is provided comprising receiving, by a first access point (AP), a first frame transmitted by a station (STA) to a second AP, and, based on the first AP not receiving a second frame from the second AP to the STA in response to the first frame, transmitting, by the first AP to the second AP, a second frame informing the second AP about the first frame. Petition 870250094447, dated 10 / 16 / 2025, pp. 203 / 332 4 / 89

[030] According to one embodiment, the first frame comprises at least one of a request frame comprising an association request frame, a reassociation request frame, a TWT request frame, a probe request frame, an RTS frame, a block recognition request frame, or a data frame.

[031] According to one embodiment, the second frame comprises a response frame comprising at least one of an association response frame, a reassociation response frame, a TWT response frame, a probe response frame, a CTS frame, or a BA frame.

[032] According to one modality, the first AP and the second AP form a multi-AP group.

[033] According to a modality, the first AP, the second AP or the STA comprises a multi-link device (MLD).

[034] According to one modality, the first link and the second link form a pair of non-simultaneous transmit and receive (NSTR) links in the STA.

[035] According to one modality, the management framework comprises an action framework which includes an action field indicating the second link and the STA.

[036] According to one embodiment, the control frame comprises a trigger frame comprising a user information list field indicating the second link and the STA.

[037] According to one embodiment, the data frame comprises a QoS null frame comprising a high-throughput (HT) control field indicating the second link and the STA.

[038] According to one embodiment, the method comprises transmitting, by the first AP to the second AP, a first indication of support by the first AP of an assisted media synchronization recovery capability between APs; and receiving, by the first AP from the second AP, a second Petition 870250094447, dated 10 / 16 / 2025, pp. 204 / 332 5 / 89 indication of support by the second AP for assisted media synchronization recovery capability between APs.

[039] According to one aspect, a device is provided that, when acting as a first AP, it is designed to perform operations comprising receiving a first frame, transmitted by a station (STA) to a second AP, which comprises a request to the second AP; and, based on the first AP not receiving an acknowledgment frame from the second AP to the STA in response to the first frame, transmitting to the second AP a second frame informing the second AP of the request comprised in the first frame.

[040] According to one aspect, a device is provided, arranged, when acting as a first STA, to perform operations comprising receiving, by a first access point (AP) from a second AP, a first frame informing the first AP of a request for the first AP transmitted by a station (STA); and based on the receipt of the first frame, transmitting, to the STA, a second frame.

[041] According to one aspect, a device is provided, when acting as a STA, arranged to: perform operations comprising transmitting, by a station (STA) to a first AP, a first frame comprising a request to the first AP; and receiving, by the STA of a second AP, a second frame in response to the first frame. BRIEF DESCRIPTION OF THE DRAWINGS

[042] Examples of several of the various forms of the present disclosure are described here with reference to the drawings: Figure 1 illustrates an example wireless communication network in which the embodiments of the present disclosure can be implemented; Figure 2 is a block diagram illustrating examples of implementations of a station (STA) and an access point (AP); Petition 870250094447, dated 10 / 16 / 2025, pp. 205 / 332 6 / 89 Figure 3 illustrates an example format for a medium access control (MAC) panel; Figure 4 illustrates an example management board that can be used as an action board; Figure 5 illustrates an example control panel that can be used as a trigger panel; Figure 6 illustrates an example data frame that can be used as a null Quality of Service (QoS) frame; Figure 7 illustrates an example format of a physical layer (PHY) protocol data unit (PPDU); Figure 8 illustrates an example reference model for a multi-link device (MLD); Figure 9 illustrates an example of an AP MLD and an associated non-AP MLD; Figure 10 illustrates an example of a multi-link configuration between an AP MLD and a non-AP MLD; Figure 11 illustrates an example of a traffic identifier (TID) to link mapping in a multi-link communication environment; Figure 12 illustrates an example multi-AP network; Figure 13 illustrates an example network that includes a coordinated AP set; Figure 14 illustrates an example multi-AP operating procedure; Figure 15 illustrates an example multi-AP sounding phase; Figure 16 illustrates an example of a multi-AP downlink data transmission phase; Figure 17 illustrates an example multi-AP uplink data transmission phase; Petition 870250094447, dated 10 / 16 / 2025, pp. 206 / 332 7 / 89 Figure 18 illustrates an example format of an AP Assistance Request (AAR) control subfield that can be used in a data frame; Figure 19 illustrates an example of an existing AP-assisted media synchronization recovery procedure; Figure 20 illustrates another example of the existing AP-assisted media synchronization recovery procedure; Figure 21 illustrates an example of an AP-assisted media synchronization recovery procedure according to a modality; Figure 22 illustrates another example of an AP-assisted media synchronization recovery procedure according to a modality; Figure 23 illustrates another example of an AP-assisted media synchronization recovery procedure according to a modality; Figure 24 illustrates an example action framework that can be used according to the modalities; Figure 25 illustrates an example QoS null frame that can be used according to the modalities; Figure 26 illustrates an example firing pattern that can be used according to the modalities; Figure 27 illustrates another example firing pattern that can be used according to the modalities; Figure 28 illustrates an example process according to an embodiment of the present disclosure; Figure 29 illustrates an example process according to an embodiment of the present disclosure; Figure 30 illustrates an example process according to an embodiment of the present disclosure; Petition 870250094447, dated 10 / 16 / 2025, pp. 207 / 332 8 / 89 Figure 31 illustrates an example process according to an embodiment of the present disclosure; and Figure 32 illustrates an example process according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[043] In the attached figures, identical references designate identical elements.

[044] In the present disclosure, several embodiments are presented as examples of how the disclosed techniques can be implemented and / or how the disclosed techniques can be practiced in environments and scenarios. It will be evident to those skilled in the relevant art that various changes in form and details can be made without departing from the scope. After reading the description, it will be evident to one skilled in the relevant art how to implement alternative embodiments. The present embodiments may not be limited by any of the exemplary embodiments described. The embodiments of the present disclosure will be described with reference to the accompanying drawings. Limitations, features, and / or elements of the revealed example embodiments may be combined to create additional embodiments within the scope of the disclosure. Any figures highlighting functionality and advantages are presented for illustrative purposes only.The revealed architecture is flexible and configurable enough that it can be used in ways other than those shown. For example, the actions listed in any flowchart can be reordered or optionally used in some modes.

[045] The modes can be configured to operate as needed. The disclosed mechanism can be executed when certain criteria are met, for example, at a station, an access point, a radio environment, a network, a combination of the above and / or similar. Example criteria may be based, at least in part, on, for example, wireless device or network node configurations, traffic load, initial system configuration, packet sizes, traffic characteristics, Petition 870250094447, dated 10 / 16 / 2025, pp. 208 / 332 9 / 89 a combination of the above and / or similar criteria. When one or more criteria are met, several example modalities can be applied. Therefore, it may be possible to implement example modalities that selectively implement disclosed protocols.

[046] In this revelation, one and an and similar phrases are to be interpreted as at least one and one or more. Similarly, any term ending with the suffix (s) is to be interpreted as at least one and one or more. In this revelation, the term may be 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 among a multitude of suitable possibilities that may, or may not, be employed by one or more of the various modalities. The terms comprise and consist of, as used herein, enumerate one or more components of the element being described. The term comprise is interchangeable with includes and does not exclude unenumerated components from being included in the element being described. In contrast, consist of provides a complete enumeration of the one or more components of the element being described.The term "based on," as used here, can be interpreted as "based, at least in part, on" rather than, for example, "based only on." The term "and / or," as used here, represents any possible combination of enumerated elements. For example, A, B, and / or C can represent A; B; C; A and B; A and C; B and C; or A, B, and C.

[047] If A and B are sets and each element of A is an element of In B, A is called a subset of B. In this descriptive report, 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") indicates that the phrase following the term "based on" is an example of one among a multitude of suitable possibilities that may or may not be employed in one or more of the various modalities. The phrase "in response to" (or equally) Petition 870250094447, dated 10 / 16 / 2025, pp. 209 / 332 10 / 89 in response to at least a) indicates that the phrase following the phrase in response to is an example of one among a multitude of suitable possibilities that may or may not be used in one or more of the various modalities. The phrase depending on (or equally depending at least on) indicates that the phrase following the phrase depending on is an example of one among a multitude of suitable possibilities that may or may not be used in one or more of the various modalities. The phrase employing / using (or equally employing / using at least) indicates that the phrase following the phrase employing / using is an example of one among a multitude of suitable possibilities that may or may not be used for one or more of the various modalities.

[048] The term configured can refer to the capability of a device, whether the device is in an operational or non-operational state. Configured can refer to specific settings on a device that affect the device's operational characteristics, whether the device is in an operational or non-operational state. In other words, hardware, software, firmware, registers, memory values, and / or the like can be configured within a device, whether the device is in an operational or non-operational state, to provide the device with specific characteristics. Terms such as a control message to trigger on a device can mean that a control message has parameters that can be used to configure specific characteristics or can be used to implement certain actions on the device, whether the device is in an operational or non-operational state.

[049] In this disclosure, parameters (or equally called, fields or information elements: IEs) can comprise one or more information objects, and an information object can 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 Petition 870250094447, dated 10 / 16 / 2025, pp. 210 / 332 11 / 89 includes K and N includes J. In one example embodiment, when one or more messages / frames comprise a plurality of parameters, this implies that a parameter in the plurality of parameters is in at least one of the one or more messages / frames, but it does not need to be in each of the one or more messages / frames.

[050] Many of the features presented are described as optional through the use of "can" or parentheses. For the sake of brevity and readability, the present disclosure does not explicitly mention each and every permutation that can be obtained by choosing from the set of optional features. The present disclosure should be interpreted as explicitly disclosing all such permutations. For example, a system described as having three optional features can be incorporated in seven ways, namely, with only one of the three possible features, with any two of the three possible features, or with three of the three possible features.

[051] Many of the elements described in the disclosed embodiments can 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 can be implemented in hardware, in software in combination with hardware, firmware, wetware (e.g., hardware with a biological element), or a combination thereof, which may be behaviorally equivalent. For example, modules can be implemented as a software routine written in a computer language configured to run on a hardware machine (such as C, C++, Fortran, Java, Basic, Matlab, or similar) or a modeling / simulation program such as Simuenclace, Stateflow, GNU Octave, or LabVIEWMathScript. It may be possible to implement modules using physical hardware that incorporates discrete or programmable analog, digital, and / or quantum hardware.Examples of programmable hardware include computers, microcontrollers, microprocessors, and application-specific integrated circuits (ASICs). Petition 870250094447, dated 10 / 16 / 2025, pp. 211 / 332 12 / 89 integrated circuits); field programmable gate arrays (FPGAs); and complex programmable logic devices (CPLDs). Computers, microcontrollers, and microprocessors are programmed using languages ​​such as assembly language, C, C++, or similar. FPGAs, ASICs, and CPLDs are frequently programmed using hardware description languages ​​(HDLs), such as VHSIC hardware description language (VHDL) or Verilog, which configure connections between internal hardware modules with less functionality in a programmable device. The technologies mentioned are often used in combination to achieve the result of a functional module.

[052] Figure 1 illustrates example 100 wireless communication networks in which embodiments of the present disclosure can be implemented.

[053] As shown in Figure 1, wireless communication networks 100 examples may include an Institute of Electrical and Electronics Engineers (IEEE) 802.11 (WLAN) infrastructure network. The WLAN infrastructure network may include one or more basic service sets (BSSs) and a distribution system.

[054] BSSs 110-1 and 110-2 each include a set of one 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 an STA 106-1, and BSS 110-2 includes an AP 104-2 and an STA 106-2 and a STA 106-3. The AP and at least one STA in a BSS perform an association procedure to communicate with each other.

[055] The DS 130 can be configured to connect the BSS 110-1 and the BSS 110-2. In this way, DS 130 can enable an extended service set (ESS) 150. Within ESS 150, AP 104-1 and AP 104-2 are Petition 870250094447, dated 10 / 16 / 2025, pp. 212 / 332 13 / 89 connected via DS 130 and may have the same service set identification (SSID).

[056] The WLAN 102 infrastructure network can be coupled to one or more external networks. For example, as shown in Figure 1, the WLAN 102 infrastructure network can be connected to another 108 network (e.g., 802.X) via a 140 portal. The 140 portal can act as a bridge connecting the DS 130 of the WLAN 102 infrastructure network to the other 108 network.

[057] The example wireless communication networks illustrated in Figure 1 may additionally 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 is configured so that they can communicate with each other using direct point-to-point communication (i.e., not through an AP).

[058] For example, in Figure 1, STA 106-4, STA 106-5, and 106-6 can be configured to form a first IBSS 112-1. Similarly, STA 106-7 and STA 106-8 can 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. Instead, the STAs within an IBSS are managed in a distributed manner. The STAs that form an IBSS can be fixed or mobile.

[059] A STA as a predetermined functional medium may include a medium access control (MAC) layer that conforms to an IEEE 802.11 standard. A physical layer interface for a radio medium may be used between APs and 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. By Petition 870250094447, dated 10 / 16 / 2025, pp. 213 / 332 14 / 89 For example, the term user can be used to denote a STA that participates in the transmission of multiple input, multiple output (MU MIMO - Multi-user Multiple Input, Multiple Output) and / or orthogonal frequency division multiple access (OFDMA - Orthogonal Frequency Division Multiple Access) uplink.

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

[061] A frequency band may include one or more sub-bands or frequency channels. For example, PPDUs conforming to the IEEE 802.11n, 802.11ac, 802.11ax and / or 802.11be standard amendments may be transmitted through the 2.4 GHz, 5 GHz and / or 6 GHz bands, each of which may be divided into multiple 20 MHz channels. PPDUs may be transmitted through a physical channel with a minimum bandwidth of 20 MHz. Larger channels may be formed through channel bonding. Petition 870250094447, dated 10 / 16 / 2025, pp. 214 / 332 15 / 89 For example, PPDUs can be transmitted through physical channels with bandwidths of 40 MHz, 80 MHz, 160 MHz, or 1120 MHz, linking multiple 20 MHz channels.

[062] Figure 2 is a block diagram 200 illustrating example implementations of an STA 210 and an AP 260. As shown in Figure 2, the STA 210 can include at least one processor 220, one memory 230, and at least one transceiver 240. The AP 260 can include at least one processor 270, one memory 280, and at least one transceiver 290. The processor 220 / 270 can be operatively connected to the transceiver 240 / 290.

[063] The 240 / 290 transceiver can be configured to transmit / receive radio signals. In one embodiment, the 240 / 290 transceiver can implement a corresponding device PHY layer (STA 210 or AP 260).

[064] In one embodiment, STA 210 and / or AP 260 may be a multi-link device (MLD), which is a device capable of operating across multiple links as defined by the IEEE 802.11be standard amendment. Thus, the STA 210 and / or AP 260 may each have multiple PHY layers. The multiple PHY layers may be implemented using one or more of the 240 / 290 transceivers.

[065] The 220 / 270 processor can 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).

[066] The 220 / 270 processor and / or the 240 / 290 transceiver may include application-specific integrated circuit (ASIC), other chipset, logic circuit and / or data processor. The 230 / 280 memory may include read-only memory (ROM), random access memory (RAM), flash memory, memory card, storage medium and / or other storage unit.

[067] When the modalities are executed by software, the techniques (or methods) described here can be executed with modules (e.g., processes, functions, and so on) that perform the functions described here. Petition 870250094447, dated 10 / 16 / 2025, pp. 215 / 332 16 / 89 The modules can be stored in memory 230 / 280 and executed by the processor 220 / 270. Memory 230 / 280 can be implemented (or positioned) inside the processor 220 / 270 or external to the processor 220 / 270. Memory 230 / 280 can be operationally connected to the processor 220 / 270 through various means known in the art.

[068] Figure 3 illustrates an example format of a MAC 300 frame. In operation, a STA can construct a subset of MAC frames for transmission and can decode a subset of received MAC frames upon validation. The specific subsets of frames that an STA can construct and / or decode can be determined by the functions supported by the STA. An STA can validate a received MAC frame using the frame check sequence (FCS) contained in the frame and can interpret certain fields of the MAC headers of all frames.

[069] As shown in Figure 3, the MAC 300 frame includes a MAC header, a variable-length frame body, and a frame check sequence (FCS).

[070] The MAC header includes a frame control field, an optional duration / ID field (not in PS-Poll frames), address fields, an optional sequence control field, an optional QoS control field (only in QoS data frames), and an optional high-throughput (HT) control field (only in +HTC frames).

[071] 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 high-throughput control (+HTC).

[072] The protocol version subfield is invariant in size and position across all revisions of the IEEE 802.11 standard. The value of the protocol version subfield is 0 for MAC frames. Petition 870250094447, dated 10 / 16 / 2025, pp. 216 / 332 17 / 89

[073] 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. The 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 subtype 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 does not contain a frame body field.

[074] The For DS subfield indicates whether a data frame is intended for DS. The From DS subfield indicates whether a data frame originates from the DS.

[075] The more fragments subfield is set to 1 in all data or management frames that have another fragment to follow from the MAC service data unit (MSDU) or MAC management protocol data unit (MMPDU) carried by the MAC frame. It is set to 0 in all other frames in which the more fragments subfield is present.

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

[077] The power management subfield is used to indicate the power management mode of an STA. Petition 870250094447, dated 10 / 16 / 2025, pp. 217 / 332 18 / 89

[078] The More Data subfield indicates for a STA in power save (PS) mode that bufferable units (BUs) are buffered for that STA on the AP. The More Data subfield is valid for individually addressed management data or 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.

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

[080] The +HTC subfield indicates that the MAC 300 frame contains an HT control field. A frame containing the HT control field is called a +HTC frame. An encapsulated control frame is a +HTC frame.

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

[082] There can be up to four address fields in the frame format. MAC 300. These fields are used to indicate the Basic Service Set Identifier (BSSID), source address (SA), destination address (DA), and address of Petition 870250094447, dated 10 / 16 / 2025, pp. 218 / 332 19 / 89 transmitting address (TA) and receiving address (RA). Certain frames may not contain some of the address fields. Certain uses of the address field can be specified by the relative position of the address field (1 to 4) within the MAC header, regardless of the type of address present in that field. Specifically, address field 1 always identifies the intended receiver(s) of the frame, and address field 2, when present, always identifies the transmitter of the frame.

[083] 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 an MMPDU. The fragment number is set to 0 in the first or only fragment of an MSDU or an 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 across all fragment retransmissions.

[084] The QoS control field identifies the traffic category (TC - traffic category) or traffic stream (TS - traffic stream) to which the MAC 300 frame belongs. The QoS control field can also indicate various other QoS-related, A-MSDU-related, and mesh-related information about the frame. This information can vary depending on the frame type, frame subtype, and transmission STA type. The QoS control field is present in all data frames where the QoS subfield of the subtype subfield is equal to 1. Petition 870250094447, dated 10 / 16 / 2025, pp. 219 / 332 20 / 89

[085] The HT control field is present in the data frames of QoS, QoS nulls, and management nulls, as determined by the +HTC subfield of the frame control field. The control frame subtype for which the HT control field is present is the encapsulated control frame. A control frame that is described as +HTC (for example, a Request to Send (RTS)+HTC, Clear to Send (CTS)+HTC, Block Acknowledgment (BlockAck)+HTC, or Block Acknowledgment Request (BlockAckReq)+HTC) implies the use of the encapsulated control frame to carry that control frame.

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

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

[088] Figure 4 illustrates an example 400 management frame that can be used as an action frame. In the example, the 400 management frame includes a MAC header, a variable-length frame body, and a frame check sequence (FCS). The MAC header includes a frame control field, a duration field, an address 1 field, an address 2 field, an address 3 field, a sequence control field, and an optional HT control field. The presence of the HT control field is determined by setting a +HTC subfield of the frame control field.

[089] As shown in Figure 4, when used as an action frame, the body of the management frame includes an action field, vendor-specific elements, integrity code element of Petition 870250094447, dated 10 / 16 / 2025, pp. 220 / 332 21 / 89 management message integrity code element (MME), message integrity code (MIC), and an authenticated mesh peering exchange element.

[090] The action field includes a category field and an action details field. The action field provides a mechanism for specifying extended management actions. The category field indicates a category of the action frame. The action details field contains the details of the action requested by the action frame. For example, the action frame might be a public action frame. As shown in Figure 4, in the public action frame format, the action details field includes a public action field, in the octet immediately following the category field, followed by a variable-length public action details field.

[091] One or more supplier-specific elements are optionally present. These elements are absent when the action field category subfield is supplier-specific.

[092] MME is present when management frame protection is negotiated, the frame is a robust group-addressed action frame and (MBSS only) the action frame category does not support group-addressed privacy, as indicated by the category values; otherwise, not present.

[093] The MIC element is present in a self-protected action frame if a shared pairwise master key (PMK) exists between the sender and receiver of that frame; otherwise, it is not present.

[094] The authenticated mesh peering exchange element is present in a self-protected action frame if a shared PMK exists between the sender and the receiver of that frame; otherwise, it is not present.

[095] Figure 5 illustrates an example format of a firing frame. 500. The 500 trigger frame can be used by an AP to allocate resources and request one or more TB PPDU transmissions from one or more STAs. Petition 870250094447, dated 10 / 16 / 2025, pp. 221 / 332 22 / 89 trigger frame 500 can also carry other information required by a response STA to transmit a TB PPDU to the AP.

[096] As shown in Figure 5, the 500 trigger frame includes a frame control field, a duration field, a receiver address (RA) field, a transmitter address (TA) field, a common information field, a user information list field, a fill field, and an FCS field.

[097] 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.

[098] The duration field 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 saving polling (PSPoll) subtype, the duration field carries an association identifier (AID) of the STA that transmitted the frame in the least significant 14 bits (LSB), and the most significant 2 bits (MSB) are both set to 1. In other frames sent by STAs, the duration field contains a duration value (in microseconds) that is used by a receiver to update a network allocation vector (NAV).

[099] 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 500 transmission trigger frame if the 500 trigger frame is addressed to STAs belonging to a single BSS. The TA field is the transmitted BSSID if the 500 trigger frame is addressed to STAs of at least two different BSSs from the multi-BSSID set.

[100] The common information field specifies a trigger frame type for the 500 trigger frame, a 500 trigger frame transmission power in dBm, and several key parameters of a TB PPDU that is transmitted by a STA in response to the 500 trigger frame. The trigger frame type of a trigger frame used by an AP to receive Petition 870250094447, dated 10 / 16 / 2025, pp. 222 / 332 23 / 89 QoS data using the UL MU operation is called a basic trigger frame. A non-EHT non-AP HE STA interprets the common information field as an HE variant. A non-AP EHT STA interprets the common information field as an HE variant if B54 and B55 in the common information field are equal to 1; and interprets the common information field as an EHT variant otherwise. The HE variant common information field and the EHT variant common information field use the same encoding method for the trigger type, UL length, plus TF, CS required, extra LDPC symbol segment, AP TX power, pre-FEC padding factor, PE disambiguation, and trigger-dependent common information subfields.

[101] The user information list field contains zero or more user information fields. There are three variants for the user information field, which are the special user information field, the EHT variant user information field and the HE variant user information field.

[102] The user special information field is a user information field that does not carry user-specific information, but carries extended common information not provided in the common information field. If the user special information field is included in the trigger frame, then the user special information field flag subfield of the EHT variant's common information field is set to 0, otherwise it is set to 1. The user special information 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 user special information field, if present, is situated immediately after the common information field of the trigger frame and carries information for the U-SIG field of a requested EHT TB PPDU.The PHY version identifier subfield indicates the PHY version of the requested TB PPDU that is not a HE TB PPDU. The subfield of... Petition 870250094447, dated 10 / 16 / 2025, pp. 223 / 332 The 24 / 89 PHY version identifier is set to 0 for EHT. Other values ​​from 1 to 7 are reserved. The UL bandwidth extension (BW Bandwidth) subfield, along with the UL BW subfield in the common information field, indicates the bandwidth of the requested 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 requested EHT TB PPDUs. The presence and length of the trigger-dependent user information subfield in the special user information field depend on the trigger frame variant.

[103] The EHT variant user information field contains a user information field per STA addressed in the 500 trigger frame. The user information field per STA includes, among others, an AID12 subfield, a RU allocation subfield, a UL FEC encoding type subfield, a UL EHT-MCS subfield, a reserved subfield, a Spatial Stream (SS) / RA-RU allocation information subfield, a UL received target energy subfield and a 160 energy saving (PS) subfield to be used by an STA in a TB PPDU transmitted in response to the 500 trigger frame and a trigger-dependent user information subfield.The RU allocation subfield in a user information field of the EHT variant in a firing frame that is not an MU-RTS firing frame, together with the UL BW subfield in the common information field, the UL BW extension subfield in the special user information field, and the PS160 subfield in the EHT variant user information field, identifies the size and location of the RU or MRU. The values ​​of the PS160 and B0 subfields of the RU allocation subfield indicate the 80 MHz frequency sub-block no. Petition 870250094447, dated 10 / 16 / 2025, pp. 224 / 332 25 / 89 which RU or MRU is located in 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 PS160 subfield values ​​indicate the 160 MHz segment in which the RU or MRU is located for 2996-tone RU, 996+484-tone MRU, and 996+484+242-tone MRU. The UL FEC encoding type subfield of the user information field indicates the type of encoding of the requested EHT TB PPDU. The UL FEC encoding type subfield is set to 0 to indicate BCC and set to 1 to indicate LDPC. The UL EHT-MCS subfield of the user information field indicates the EHTMCS of the requested EHT TB PPDU. The SS allocation subfield of the EHT variant user information field indicates the spatial flows of the requested EHT TB PPDU.The UL received target power subfield indicates the expected received signal strength, measured at the AP antenna connector and averaged across the antennas, for the EHT portion of the EHT TB PPDU transmitted in the assigned RU. The trigger-dependent user information subfield can be used by an AP to specify a preferred access category (AC) per STA. The preferred AC defines 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 TB PPDU duration per participating STA. The RA-RU information subfield is reserved in the EHT variant user information field.

[104] The padding field is optionally present in the 400 trigger frame to extend the frame length to give the receiving STAs sufficient time to prepare a response for transmitting a SIFS after the frame is received. The padding field, if present, is at least two octets long and is set to all 1s. Petition 870250094447, dated 10 / 16 / 2025, pp. 225 / 332 26 / 89

[105] The FCS field is used by an STA to validate a received frame and interpret certain fields of a frame's MAC headers.

[106] Figure 6 illustrates a sample 600 data frame that can be used as a QoS null frame. A QoS null frame refers to a QoS data frame with an empty frame body. The QoS null frame includes a QoS control field and an optional HT control field that may contain a buffer status report (BSR) control subfield. A QoS null frame indicating buffer status information can be transmitted by an STA to an AP.

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

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

[109] The policy recognition indicator subfield, along with other information, identifies the recognition policy followed by the delivery of the MPDU (e.g., normal recognition, implicit block recognition request, no recognition, block recognition, etc.)

[110] The queue size subfield is an 8-bit field that indicates the amount of traffic buffered for a given TC or TS in 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 null QoS frames sent by an STA when bit 4 of the field Petition 870250094447, dated 10 / 16 / 2025, pp. 226 / 332 27 / 89 QoS control is set to 1. The AP can use information contained in the queue size subfield to determine the TXOP duration assigned to the STA or to determine the uplink (UL) resources assigned to the STA.

[111] In a frame sent by or to a non-high-efficiency STA (without (HE), the following rules can be applied to the queue size value:

[112] The queue size value is the approximate total size, rounded to the nearest multiple of 256 octets and expressed in units of 256 octets, of all MSDUs and A-MSDUs buffered in the STA (excluding the MSDU or A-MSDU contained in this 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.

[113] A queue size value of 0 is used only to indicate the absence of any buffered traffic in the queue used for the specified TID.

[114] A queue size value of 254 is used for all sizes greater than 64768 octets.

[115] A queue size value of 255 is used to indicate an unspecified or unknown size.

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

[117] The queue size value, QS, is the approximate total size in octets of all MSDUs and A-MSDUs buffered in the STA (including MSDUs or A-MSDUs contained in the same PSDU as the frame containing the queue size subfield) 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.

[118] The queue size subfield includes a scale-shift factor subfield in bits B14-B15 of the QoS control field and an unscaled value, UV, in bits B8-B13 of the QoS control field. The Petition 870250094447, dated 10 / 16 / 2025, pp. 227 / 332 The 28 / 89 subfield of the scale change factor provides the scale change factor, SF.

[119] A STA obtains the queue size, QS, from a control field of Received QoS, which contains a scaling factor, SF, and an unscaled value, UV, as follows: QS = xUV, if SF is equal to 0; 1024 + 256 x UV, if SF is equal to 1; 17408 + 2048 x UV, 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 equals 3 and UV equals 62; Undetermined or Unknown, if SF equals 3 and UV equals 63.

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

[121] The HT control field may include an aggregate control subfield (A-Control). The A-Control subfield may include a control list subfield containing one or more control subfields.

[122] The control subfield may be 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 elevated ACI subfield, a factor subfield Petition 870250094447, dated 10 / 16 / 2025, pp. 228 / 332 29 / 89 scale change, a high queue size subfield and a total queue size subfield of the HT control field.

[123] The ACI bitmap subfield indicates the access categories 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 total queue size 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.

[124] The delta TID subfield, together with the ACI bitmap subfield values, indicate the number of TIDs to which the STA is reporting buffer status.

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

[126] The scale change factor subfield indicates the unit SF, in octets, of the high queue size and total queue size subfields.

[127] The high queue size subfield indicates the amount of buffered traffic, in SF unit octets, for the AC identified by the high ACI subfield, which is destined for the STA identified by the receiver address of the frame containing the BSR control subfield.

[128] The total queue size subfield indicates the amount of buffered traffic, in SF unit octets, for all ACs identified by the ACI bitmap subfield, which is destined for the STA identified by the receiver address of the frame containing the BSR control subfield.

[129] The queue size values ​​in the high queue size and total queue size subfields are the total sizes, rounded to the nearest whole number. Petition 870250094447, dated 10 / 16 / 2025, pp. 229 / 332 30 / 89 nearest multiple of SF octets, of all MSDUs and A-MSDUs buffered in the STA (including 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 the AC(s) that is / are specified in the elevated ACI and ACI bitmap subfields, respectively.

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

[131] The 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 MSDUs to a peer MAC entity. This asynchronous MSDU transport is performed on a connectionless basis.

[132] Figure 7 illustrates an example PPDU format. As shown, the PPDU can include a PHY preamble, a PHY header, a PSDU, and tail and padding bits.

[133] A PSDU can 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 MPDU frame body can include an MSDU or an A-MSDU.

[134] By default, MSDU transport is done on a best-effort basis. That is, there is no guarantee that a transmitted MSDU will be successfully delivered. However, the QoS setup uses a traffic identifier (TID) to specify differentiated services based on MSDUs. Petition 870250094447, dated 10 / 16 / 2025, pp. 230 / 332 31 / 89

[135] A STA can differentiate MSDU delivery according to the designated traffic category (TC) or traffic flow (TS) of the individual MSDUs. MAC sublayer entities determine a user priority (UP) for an MSDU based on a TID value provided with the MSDU. The QoS installation 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 between 2 and 3.

[136] An MSDU with a specific UP is said to belong to a traffic category with that UP. The UP can be assigned to each MSDU at the Medium Access Control Service (MAC SAP) access point directly in a UP parameter. An A-MPDU can include MPDUs with different TID values.

[137] A STA can deliver buffer status reports (BSRs) to assist an AP in allocating UL MU resources. The STA can implicitly deliver BSRs in the QoS control field or in the BSR control subfield of any frame transmitted to the AP (unsolicited BSR) or explicitly deliver BSRs in a frame sent to the AP in response to a BSRP trigger frame (solicited BSR).

[138] 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, a delta TID, a high-priority AC, and two queue sizes.

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

[140] The STA can 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 can set the subfield of Petition 870250094447, dated 10 / 16 / 2025, pages 231 / 332 32 / 89 queue size for 255 to indicate an unknown / unspecified queue size for that TID. The STA can aggregate multiple QoS data frames or null QoS frames into an A-MPDU to report the queue size for different TIDs.

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

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

[143] A HE STA can report the queue size for ACs indicated by the ACI bitmap subfield in the total queue size subfield of the BSR control subfield. The STA can set the total queue size subfield to 255 to indicate unknown / unspecified BSRs for those ACs.

[144] Figure 8 illustrates an example reference model for a multi-link device (MLD). An MLD is an entity capable of managing communication across multiple links. The MLD can be a logical entity and can have more than one affiliated station (STA). An MLD can be an access point MLD (AP MLD) where an STA affiliated to the MLD is an AP STA (or an AP). An MLD can be a non-access point MLD (non-AP MLD) where an STA affiliated to the MLD is a non-AP STA (or an STA).

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

[146] As shown in Figure 8, an MLD can have a single Service MAC Access Point (SAP MAC) for the LLC layer, which includes a Data MAC service. MLD can support multiple MAC sublayers. Petition 870250094447, dated 10 / 16 / 2025, pp. 232 / 332 33 / 89 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.

[147] The SME is responsible for coordinating the MAC sublayer management entities (MLMEs) of the MLD-affiliated STAs 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).

[148] 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 supported by both MLDs. The authenticator and MAC address of an AP MLD can be identified by the same MAC address of the AP MLD. The supplicant and MAC address of a non-AP MLD can be identified by the same MAC address of the non-AP MLD.

[149] Figure 9 illustrates an example of an AP MLD and an associated non-AP MLD.

[150] 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 can 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.

[151] In general, the MAC addresses of an MLD and its affiliated STAs are different from each other. For example, as shown in Figure 9, the AP MLD may have a MAC address M, AP 1 may have a MAC address w, and AP2 may have a 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. Petition 870250094447, dated 10 / 16 / 2025, pp. 233 / 332 34 / 89

[152] As shown in Figure 9, with each MLD, the sublayer of MAC can be further divided into an upper MLD MAC sublayer and a lower MLD MAC sublayer. The upper MLD MAC sublayer performs functionalities that are common to all links. The lower MLD MAC sublayer performs functionalities that are local to each link. Some of the functionalities require the joint processing of both the upper and lower MLD MAC sublayers.

[153] MLD's 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 group temporal key (GTK) / integrity CTK (IGTK) / beacon IGTK (BIGTK) distribution; Assignment of sequence number (SN) / packet number (PN) to frames to be encrypted by pairwise transient key (PTK) for single-cast frames; Encryption / decryption using PTK for single-cast frames; Selection of the lower MAC sublayer of MLD for transmission (TID to link mapping); Reordering of packets to ensure delivery in order for each block recognition session; Block recognition scoreboarding for individually addressed frames (in collaboration with the lower MAC sublayer of MLD); optionally, the upper MAC sublayer of MLD delivers Petition 870250094447, dated 10 / 16 / 2025, pages 234 / 332 35 / 89 the block acknowledgment record on a link to the lower MAC sublayer of MLD from other links; and exchange / indication of MLD-level management information through the lower MAC sublayer of MLD.

[154] Lower MAC sublayer functions (MLD) may include: GTK / IGTK / BIGTK maintenance specific to the link (between an AP affiliated with the AP MLD and a STA affiliated with the non-AP MLD); encryption / decryption / link-specific integrity protection and PN assignment using GTK / IGTK / BIGTK (between an AP affiliated with the AP MLD and a non-AP MLD affiliated STA); Exchange / indication of link-specific management information (e.g., radio beacon); Exchange / indication of link-specific control information (e.g., RTS / CTS, acknowledgments, etc.); energy saving state and mode; MAC address filtering for frame reception; and block recognition scoreboarding for individually addressed frames (in collaboration with the upper MAC sublayer of MLD); optionally, the lower MAC sublayer of MLD receives the block recognition record on the other links from the upper MAC sublayer of MLD.

[155] The (re)configuration of multiple links between a non-AP MLD and a AP MLD may include a (re)association request / response frame exchange. A (re)association request / response frame exchange for a multi-link configuration may include both frames carrying a basic multi-link element.

[156] In the (re)association request form, the non-AP MLD indicates the links that are requested for (re)configuration and the capabilities and operational parameters of the requested links. The non-AP MLD can request the (re)configuration of links with a subset of APs affiliated with the MLD of Petition 870250094447, dated 10 / 16 / 2025, pages 235 / 332 36 / 89 AP. The links that are requested for (re)configuration and the capabilities and operational parameters of the requested links are independent of the existing configuration links with an associated AP MLD and the capabilities and operational parameters of the configuration links.

[157] In the (re)association response frame, the AP MLD can indicate the requested links that are accepted and the requested links that are rejected for (re)configuration, and the capabilities and operational parameters of the requested links. The AP MLD can accept a subset of the links that are requested for (re)configuration. 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.

[158] An MLD that requests or accepts the (re)configuration of multiple links for any two links ensures that each link is located on a different non-overlapping channel. After successful (re)configuration of multiple links between a non-AP MLD and an AP MLD, the non-AP MLD and the AP MLD configure links for multi-link operation, and the non-AP MLD is (re)associated with the AP MLD. For each link configuration, 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 link configuration, the functionalities between a non-AP STA and its associated AP are activated, unless the functionalities have been extended to the MLD level or specified otherwise.

[159] Figure 10 illustrates an example of a multi-link configuration 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.

[160] The MLD non-AP can initiate the configuration of multiple links by STA not AP 1 sending a membership request frame to AP 1 Petition 870250094447, dated 10 / 16 / 2025, pp. 236 / 332 37 / 89 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 indicating the MAC address of the non-AP MLD and the complete information of non-AP STA 1, non-AP STA 2, and non-AP STA 3. The association request frame can request the configuration of three links between the non-AP MLD and the AP MLD (one link between AP 1 and non-AP STA 1, one link between AP 2 and non-AP STA 2, and one link between AP 3 and non-AP STA 3).

[161] The AP MLD can respond to the multi-link configuration request from the AP by sending an association response frame to the 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 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 MAC address of the AP MLD and the complete information of AP 1, AP 2, and AP 3. The association response frame signals the successful multi-link configuration by configuring three links between the non-AP MLD and the 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).

[162] By default, all TIDs on the non-AP MLD are mapped to all configuration links for both uplink and downlink. The TID-to-link mapping mechanism allows an AP MLD and a non-AP MLD that has performed or is performing multi-link configuration to specify how UL and DL QoS traffic corresponding to different TIDs (e.g., between 0 and 7) can be assigned to configuration links. In a negotiated TID-to-link mapping, a TID can be mapped to a set of links, which is a subset of configuration links, in the range from a single configuration link to all configuration links. Petition 870250094447, dated 10 / 16 / 2025, pp. 237 / 332 38 / 89

[163] A configuration link is defined as enabled for a non-AP MLD if at least one TID is mapped to that link in DL or UL and is defined as disabled if no TID is mapped to that link in DL and UL. At any given time, a TID is always mapped to at least one configuration link in DL and UL, meaning that a TID-to-link mapping change can only be valid and appropriate if it does not result in a TID with a set of mapped links made up of zero configuration links.

[164] By default, all configuration links are enabled. If a link is enabled for a non-AP MLD, it can 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 can be transmitted on that link in the direction (DL / UL) corresponding to the TID-to-link mapping. Individually addressed control frames and management frames can be sent on any enabled link between an affiliated STA of the non-AP MLD and a corresponding AP of the AP MLD, in both DL and UL.

[165] 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.

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

[167] If a TID is mapped in DL to a set of links enabled for a non-AP MLD, the non-AP MLD can retrieve individually addressed BUs buffered in the AP MLD that are MSDUs or A-MSDUs matching the TID, on any link in the set of links enabled. Conversely, the AP MLD can use any link within the set of links enabled to transmit MSDUs or A-MSDUs. Petition 870250094447, dated 10 / 16 / 2025, pp. 238 / 332 39 / 89 individually addressed, corresponding to the TID, subject to the power status of the non-AP STA on each of the links used.

[168] If the default mode is used, the non-AP MLD can retrieve buffered BUs from the AP MLD on any configuration link, although the AP MLD can recommend a link.

[169] A non-AP MLD can retrieve buffered BUs that are Buffered MMPDUs in the AP MLD on any enabled link. An AP MLD can use any enabled link to transmit individually addressed buffered management frames that are not metering MMPDUs, subject to the power state of the non-AP STA on the link used.

[170] If an 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 TIDs mapped to the non-AP MLD; and MMPDUs that are not metering 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.

[171] As mentioned above, in standard mapping mode, all TIDs are mapped to all configuration links for DL ​​and UL, and all configuration links are enabled. A non-AP MLD and an AP MLD performing multi-link configuration must operate under this mode if a TID-to-link mapping negotiation for a different mapping has not occurred, has not been adequate, or has been disassembled.

[172] In a multi-link (re)configuration procedure, a A non-AP MLD can 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. Petition 870250094447, dated 10 / 16 / 2025, pp. 239 / 332 40 / 89

[173] After receiving the (re)association request frame containing the TID-to-link mapping element, the AP MLD may respond to the (re)association request frame according to the following rules. The AP MLD may 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 the (re)configuration of multiple links for all links on which at least one TID is requested to be mapped. In this case, the non-AP MLD includes a TID-to-link mapping element in the (re)association response frame. Otherwise, the non-AP MLD indicates the 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.

[174] After a proper (re)configuration of multiple links, in order to negotiate a new TID-to-link mapping, an initiating MLD can send an individually addressed TID-to-link mapping request frame to a responding MLD that has indicated TID-to-link mapping negotiation support.

[175] Upon 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 the 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 response frame of Petition 870250094447, dated 10 / 16 / 2025, pp. 240 / 332 41 / 89 TID-to-link mapping including the TID-to-link mapping element in the TID-to-link mapping response frame.

[176] An MLD can 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.

[177] 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. Additionally, an AP MLD may take into account the traffic flow(s) affiliated with the non-AP MLD and the capabilities and restrictions (if any) of the non-AP MLD.

[178] When two MLDs have negotiated a TID-to-link mapping, either MLD can dismantle the negotiated TID-to-link mapping by sending an individually addressed TID-to-link mapping dismantle frame. After dismantling, the MLDs operate in standard mapping mode.

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

[180] When an MLD has correctly negotiated with a peer MLD a TID-to-link mapping of uplink and / or downlink in which the bit position i of a link mapping field n in the TID-to-link mapping element is set to 0, a TID n should not be mapped to the link associated with link ID i in uplink and / or downlink. When an MLD has correctly negotiated with a peer MLD a TID-to-link mapping of uplink and / or downlink in which the bit position i of a link mapping field n Petition 870250094447, dated 10 / 16 / 2025, pp. 241 / 332 42 / 89 in the TID-to-link mapping element is defined as 1, the TID n is mapped to the link associated with the link ID i in uplink and / or downlink.

[181] Figure 11 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 with three affiliated APs and a non-AP MLD with three affiliated STAs.

[182] During or after the configuration of multiple links, the non-AP MLD and the AP MLD can negotiate a TID-to-link mapping. The TID-to-link mapping maps TIDs on the non-AP MLD to UL and DL to configure links between the AP MLD and the non-AP MLD. For example, as shown in Figure 11, the TID-to-link mapping can map TIDs 0 to 6 to both UL and DL for link 1 and TID 7 to both UL and DL for link 2. In this way, links 1 and 2 are enabled and link 3 is disabled. The TID-to-link mapping negotiation can 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.

[183] ​​Figure 12 illustrates an example 1200 multi-AP network. The multi- network The example AP 1200 can be a multi-AP network according to the Wi-Fi Alliance standard specification for multi-AP networks. As shown in Figure 12, the multi-AP 1200 network can include a multi-AP controller 1202 and a plurality of multi-AP groups (or multi-AP sets or AP candidate sets), including multi-AP group 1204, multi-AP group 1206, and multi-AP group 1208.

[184] The 1202 multi-AP controller can be a logical entity that implements the logic to control the APs in the 1200 multi-AP network. The 1202 multi-AP controller can receive information and capacity measurements from the APs and can trigger AP control commands and operations on the APs. The Petition 870250094447, dated 10 / 16 / 2025, pages 242 / 332 The 43 / 89 multi-AP 1202 controller can also provide integration functionality to integrate and provision APs in the multi-AP 1200 network.

[185] Multi-AP group 1204, multi-AP group 1206 and multi-AP group 1208 can each include a plurality of APs. APs in a multi-AP group are within communication range of each other. However, the APs in a multi-AP group do not need to have the same primary channel. As used here, the primary channel for an AP refers to a standard channel that the AP monitors for management frames and / or uses to transmit radio beacon frames. For a STA associated with an AP, the primary channel refers to the AP's primary channel, which is advertised through the AP's radio beacon frames.

[186] In one approach, one of the APs in a multi-AP group can be designated as a master AP. The master AP designation can be made by the 1202 multi-AP controller or by the APs in the multi-AP group. The master AP of a multi-AP group can be fixed or can change over time among the APs in the multi-AP group. An AP that is not the master AP of the multi-AP group is known as a slave AP.

[187] In one approach, a multi-AP group or a set of AP candidates is a set of APs that can initiate or participate in multi-AP coordination. An AP in a multi-AP group can participate as a slave AP in multi-AP coordination initiated by a master AP in the same multi-AP group. At least one AP in a multi-AP group must be able to be a master AP.

[188] In one approach, APs in a multi-AP group can coordinate with each other, including coordinated transmissions within the multi-AP group. One aspect of coordination may include coordination to perform multi-AP transmissions within the multi-AP group. As used herein, a multi-AP transmission is a transmission event in which multiple APs (from a multi-AP group or a multi-AP network) transmit simultaneously over a period. The period of simultaneous AP transmission may be a continuous period. Petition 870250094447, dated 10 / 16 / 2025, pp. 243 / 332 44 / 89

[189] Multi-AP group coordination can be enabled by the multi-AP controller and / or the multi-AP group master AP. In one approach, the multi-AP controller and / or the master AP can control the time and / or frequency sharing in a TXOP. For example, when one of the APs (e.g., the master AP) in the multi-AP group obtains a TXOP, the multi-AP controller and / or the master AP can control how the TXOP's time / frequency resources should be shared with other APs in the multi-AP group. In one implementation, the multi-AP group AP that obtains a TXOP becomes the multi-AP group master AP. The master AP can then share a portion of its obtained TXOP (which may be the entire TXOP) with one or more other APs in the multi-AP group.

[190] Multi-AP operation can be enabled by at least two APs that support multi-AP coordination within one or more multi-AP groups. The APs can support multi-AP broadcast schemes in a multi-AP network. A master AP can coordinate with slave AP(s) to enable multi-AP coordination and to support a multi-AP broadcast. The slave AP(s) can participate in a multi-AP broadcast. The master AP can select the slave AP(s) that are suitable for the multi-AP broadcast. Slave APs can be candidates for a multi-AP broadcast before being assigned by the master AP.

[191] Multi-AP transmission schemes may include transmission schemes such as coordinated OFDMA, coordinated time division multiple access (TDMA), coordinated spatial reuse, coordinate beamforming, joint transmission or reception (JT / JR), or a combination of two or more of the schemes mentioned above.

[192] Coordinated OFDMA and coordinated TDMA can be categorized as coordinated TXOP, in which the frequency or time resources of a TXOP can be used to coordinate interference. Coordinated spatial reuse (CSR) can provide the reuse of Petition 870250094447, dated 10 / 16 / 2025, pp. 244 / 332 45 / 89 spatial domain of neighboring BSSs adjusting the transmission powers of coordinated APs. Coordinated beamforming (CBF) can provide dedicated null guidance with spatial radiation based on channel state information (CSI) feedback from coordinated APs with the aid of multiple antennas to suppress interference. JT / JR can use pre-coding or distributed MIMO detection, via shared CSI, for data streams between multiple APs.

[193] Figure 13 illustrates an example 1300 network that includes a coordinated AP set. As shown in Figure 13, the coordinated AP set can include two APs - AP 1302-1 and AP 1302-2. The coordinated AP set can be a subset of an established multi-AP group. At least one STA can be associated with each of the APs 1302-1 and 1302-2. For example, a STA 1304-1 can be associated with AP 1302-1 and a STA 13042 can be associated with AP 1302-2.

[194] APs 1302-1 and 1302-2 can belong to the same ESS as described above in Figure 1. In this case, APs 1302-1 and 1302-2 can be connected by a DS to support ESS features. Additionally, as part of a coordinated AP set, APs 1302-1 and 1302-2 can be connected by a backhaul. The backhaul is used to quickly share information between APs to support coordinated transmissions. The shared information can be channel state information or data to be sent to associated STAs. The backhaul can be a wired backhaul or a wireless backhaul. A wired backhaul is preferred for high-capacity information transfer without overloading the main radios of the APs. However, a wired backhaul may require a higher deployment cost and may place greater restrictions on AP placement. A wireless backhaul is preferred due to its lower deployment cost and flexibility regarding access point placement.However, this is because a wireless backhaul relies on the main radios of the access points (APs) to transfer data. Petition 870250094447, dated 10 / 16 / 2025, pp. 245 / 332 46 / 89 information, the APs cannot transmit or receive any data while wireless backhaul is being used.

[195] Typically, one of the 1302-1 and 1302-2 APs can act as a master AP and the other as a slave AP. The master AP is the AP that owns the TXOP. The master AP shares frequency resources during the TXOP with the slave AP. When there are more than two APs in the coordinated set, a master AP can share its TXOP with only a subset of the coordinated AP set. The role of the master AP can change over time. For example, the role of master AP can be assigned to a specific AP for a period of time. Similarly, the role of slave AP can be chosen by the master AP dynamically or can be pre-assigned for a period of time.

[196] Depending on the capabilities of the APs in a coordinated AP set, the APs can only perform certain types of coordinated transmissions. For example, in Figure 13, if AP 1302-1 supports JT and CSR while AP 13022 supports CSR and CBF, both APs can only perform CSR as a coordinated transmission scheme. An AP may also prefer to perform single AP transmissions for a period of time if the benefit of coordinated transmission does not outweigh some disadvantages of coordinated transmission, such as reduced flexibility and higher computational power required.

[197] CSR is a type of multi-AP coordination that can be supported by AP 1301-1 and AP 1302-2, as shown in Figure 13. Spatial reuse using CSR can be more stable than non-AP coordinated spatial reuse schemes, such as packet detect-based SR (PD) of overlapping basic service set (OBSS) and PSR-based SR. For example, in example 1300, APs 1302-1 and 1302-2 can perform a joint polling operation in order to measure path loss (PL) on the paths of the 1300 network. For example, the joint polling operation can result in the measurement of Petition 870250094447, dated 10 / 16 / 2025, pp. 246 / 332 47 / 89 PL 1308 for the path between APs 1302-1 and 1302-2, path loss 1310 for the path between AP 1302-1 and STA 1304-2, and path loss 1312 for the path between AP 1302-2 and STA 1304-1. The measured path loss information can then be shared between APs 1302-1 and 1302-2 (e.g., using backhaul) to allow simultaneous transmissions by APs 1302-1 and 1302-2 to their associated STAs 1304-1 and 1304-2, respectively. Specifically, one of the APs 1302-1 and 1302-2 obtains a TXOP to become the master AP. The master AP can then send a CSR advertisement frame to the other AP(s). In one mode, the master AP can perform a probing operation before sending the CSR advertisement frame to probe slave APs regarding packet availability for transmission. If at least one slave AP responds indicating packet availability, the master AP can proceed with sending the CSR advertisement frame.In CSR announcement, the master AP can limit the transmission power of a slave AP to protect its own transmission to its target STA. The slave AP can similarly protect its own transmission to its target STA by choosing a modulation scheme that allows a high enough signal-to-interference ratio (SIR) margin to withstand interference due to the master AP's transmission to its target STA.

[198] Figure 14 illustrates a 1400 example of a multi-AP operating procedure. In the 1400 example, the multi-AP operating procedure is illustrated in relation to a multi-AP network that includes APs 1402 and 1404 and STAs 1406 and 1408. In one example, APs 1402 and 1404 can form a multi-AP group. AP 1402 can be the master AP and AP 1404 can be a slave AP of the multi-AP group. For example, AP 1402 can obtain a TXOP, making it the master AP of the multi-AP group.Alternatively, the AP 1402 can be designated as the master AP by a multi-AP controller.

[199] As shown in Figure 14, the multi-operation procedure An AP can include a series of time phases, each of which can contain a plurality of frame exchanges within the multi-AP network. Specifically, Petition 870250094447, dated 10 / 16 / 2025, pp. 247 / 332 48 / 89 The multi-AP operation procedure may include a multi-AP selection phase 1410, a multi-AP data sharing phase 1412, a multi-AP probing phase 1414 and a multi-AP data transmission phase 1416.

[200] A multi-AP network can perform a multi-AP operation based on a specific multi-AP transmission scheme. The multi-AP transmission scheme can be chosen by the master AP based on the capabilities of the slave APs in a multi-AP group. Before a multi-AP operation, a slave AP can inform the master AP about capacity information related to the slave AP, including the capabilities to support one or more multi-AP transmission schemes. The slave AP can also inform the master AP about the slave AP's BSS information and link quality information for STAs associated with the slave AP. The master AP can receive information related to all available slave APs. Information related to slave APs can include capacity information, BSS information, and link quality information.Based on the information provided by the available slave APs, the master AP can determine during a multi-AP selection phase which slave APs to assign for multi-AP transmission and a specific multi-AP transmission scheme to use during the multi-AP transmission.

[201] The 1410 multi-AP selection phase may include procedures for requesting, selecting, or assigning slave AP(s) to a multi-AP group by a master AP. As seen in Figure 14, the multi-AP selection phase may include transmissions of frame 618 from AP 1402 and frame 1420 from AP 1404. AP 1402 may transmit frame 1418 to request information related to the buffer status of AP 1404. In response, AP 1404 may transmit frame 1420 to inform AP 1402 of its status and the buffer status of associated STAs and / or whether it intends to join the multi-AP operation. The 1410 multi-AP selection phase may also be used to exchange information regarding the multi-AP operation, including AP BSS information and link quality information between each AP and its associated STAs, by Petition 870250094447, dated 10 / 16 / 2025, pp. 248 / 332 49 / 89 example. An AP's BSS information may include an AP BSS ID, identifiers and / or capabilities of STAs belonging to the BSS, information regarding STA polling capabilities, information regarding the AP's MIMO capabilities, etc. Link quality information may include received signal strength indicator (RSSI), signal-to-noise ratio (SNR), signal-to-interference-plus-noise ratio (SINR), channel state information (CSI), channel quality indicator (CQI).

[202] The 1412 multi-AP data sharing phase may include procedures for sharing data frames to be transmitted by APs to associated STAs between the master AP and the selected slave AP(s) via direct connections between APs. The 1412 phase may be optional for some multi-AP data transmission schemes. For example, the 1412 phase may be required for JT / JR, since data frames may be exchanged between APs before or after the 1416 multi-AP data transmission phase.

[203] The 1412 multi-AP data sharing phase can be performed using a wired backhaul, an in-channel wireless backhaul, or an out-of-channel wireless backhaul. In some cases, the 1412 multi-AP data sharing phase can be performed via an in-channel backhaul, for example, using the same wireless channel used to transmit / receive data to / from STAs. For example, as shown in Figure 14, in the 1412 phase, AP 1402 can transmit a 1422 frame, which can be received by AP 1404. The 1422 frame can include MPDUs that AP 1402 wants to transmit to associated STAs using a multi-AP operation. Similarly, AP 1404 can transmit a 1424 frame, which can be received by AP 1402. The 1424 frame may include MPDUs that AP 1404 wishes to transmit to associated STAs using a multi-AP operation. Petition 870250094447, dated 10 / 16 / 2025, pp. 249 / 332 50 / 89

[204] The 1414 multi-AP probing phase may include procedures for multi-AP channel probing, including channel estimation and feedback of channel estimates between the master AP, the candidate slave AP(s), and the associated STAs. The 1414 phase may be optional for some multi-AP transmission schemes, such as COFDMA, CDTMA, and CSR. For example, the 1414 phase may be performed by the master AP to assist in resource unit allocation when orchestrating a COFDMA transmission.

[205] The 1416 multi-AP data transmission phase may include the exchange of data frames between the master AP, the slave AP(s), and their associated STAs based on the multi-AP transmission scheme(s) determined by the master AP. Depending on the multi-AP transmission scheme(s) to be used, the 1416 phase may include optional synchronization between APs in the multi-AP group, prior to the exchange of data frames between APs and STAs within the multi-AP group.

[206] The order of phases 1410, 1412, 1414, and 1416 may differ from that shown in Figure 14. For example, in COFDMA, phase 1416 may occur immediately after phase 1410, while in JT / JR, phase 1412 may occur after phase 1410. Furthermore, as mentioned above, some phases may be optional and may or may not be present. For example, phase 1414 may not be required for COFDMA, but may be required for JT / JR.

[207] Figure 15 illustrates an example 1500 of a multi-phase sounding AP. The multi-AP 1500 probing phase can be an example of the multi-AP 1414 probing phase. As shown in Figure 15, example 1500 can include a master AP 1502 and a slave AP 1504 of a multi-AP group. Example 1500 can additionally include a STA 1506 associated with AP 702 and a STA 1508 associated with AP 1504.

[208] As shown in Figure 15, the multi-AP 1500 probing phase may include frame exchanges to allow AP 1502 (the master AP) to acquire channel state information (CSI) from channels in the multi-AP group. In a Petition 870250094447, dated 10 / 16 / 2025, pp. 250 / 332 51 / 89 implementation, phase 1500 may include a first sub-phase 1510 and a second sub-phase 1512.

[209] During the first subphase 1510, APs can initiate channel probing and STAs can estimate CSI. For example, AP 1502 can transmit a 1514 frame to AP 1504 (the slave AP) to trigger multi-AP probing. The 1514 frame can comprise a multi-AP trigger frame. Subsequently, APs 1502 and 1504 can transmit, respectively, 1516-1 and 1516-2 advertisement frames to their respective associated STAs 1506 and 1508 to announce the transmission of probing frames. The 1516-1 and 1516-2 frames can comprise multi-AP null data packet announcement (NDPA) frames. The 1516-1 and 1516-2 frames can be transmitted simultaneously. Next, APs 1502 and 1504 can transmit frames 1518-1 and 1518-2 to STAs 1506 and 1508, respectively. Frames 1518-1 and 1518-2 may comprise multiAP null data packet (NDP) frames.STAs 1506 and 1508 receive frames 1518-1 and 1518-2, respectively, and perform channel estimation of channels from AP 1502 to STA 1506 and from AP 1504 to STA 1508, respectively.

[210] During the second subphase 1512, the APs can initiate a procedure for the STAs to provide feedback on channel estimates to the APs. For example, AP 1502 can transmit a frame 1520 to trigger STAs 1506 and 1508 to transmit their channel estimates to APs 1502 and 1504, respectively. Frame 1520 can comprise a multi-AP trigger frame. In response, STAs 1506 and 1508 can transmit frames 1522 and 1524, respectively, including feedback on channel estimates to APs 1502 and 1504, respectively. Frames 1522 and 1524 can comprise NDP feedback frames. Feedback on channel estimates may include NDP feedback, CSI-related information, a beamforming report (BFR), or a channel quality indication (CQI) report. Petition 870250094447, dated 10 / 16 / 2025, pp. 251 / 332 52 / 89

[211] Figure 16 illustrates a 1600 example of a multi-AP downlink data transmission phase. The 1600 multi-AP downlink data transmission phase can be an example of the 1516 multi-AP data transmission phase. As shown in Figure 16, the 1600 example can include a 1602 master AP and a 1604 slave AP from a multi-AP group. The 1600 example can additionally include a 1606 STA associated with the 1602 AP and a 1608 STA associated with the 1604 AP.

[212] As shown in Figure 16, the downlink multi-AP 1600 data transmission phase may include frame exchanges to allow master AP 1602 to coordinate with slave AP 1604 to execute specific multi-AP transmission schemes with their associated STAs 1606 and 1608, respectively. Multi-AP transmission schemes may include COFDMA, CTDMA, CSR, CBF, JT / JR, or a combination of two or more of the aforementioned schemes.

[213] As shown in Figure 16, master AP 1602 can start phase 1600 by transmitting a 1610 frame to AP 1604. The 1610 frame may include information related to AP 1604 (e.g., an AP 1604 identifier), synchronization information, information related to a specific multi-AP transmission scheme to be used, and / or information related to a resource unit (RU) for use by AP 1604 to acknowledge the 1610 frame. The 1610 frame may comprise a control frame. For example, the 1610 frame may comprise a multi-AP trigger frame.

[214] Slave AP 1604 can receive frame 1610 and can use the synchronization information to synchronize with master AP 1602. Subsequently, APs 1602 and 1604 can perform data transmission to their associated STAs 1606 and 1608, respectively. Specifically, AP 1602 can transmit a data frame 1612 to its associated STA 1606 and AP 1604 can transmit a data frame 1614 to its associated STA 1608. Depending on the multi-transmission scheme Petition 870250094447, dated 10 / 16 / 2025, pages 252 / 332 53 / 89 The AP used, APs 1602 and 1604, can transmit frames 1612 and 1614, respectively, to STAs in different BSSs. For example, when the multi-AP transmission scheme is JT / JR, AP 1602 can also transmit frame 1612 to STA 1608 associated with slave AP 1604, and AP 1604 can also transmit frame 1614 to STA 1608 associated with AP 1604. The capabilities for transmitting and receiving frames 1612 and 1614 may depend on the specific multi-AP transmission scheme adopted.

[215] STA 1606 and 1608 can acknowledge frames 1612 and 1614, respectively. For example, STA 1606 can transmit a frame 1616 to AP 1602, and STA 1608 can transmit a frame 1618 to AP 1604. Frames 1616 and 1618 can comprise block acknowledgment (BA) frames. STA 1606 and 1608 can also transmit frames 1616 and 1618 to APs in different BSSs, when required by the multi-AP transmission scheme used. For example, when the multi-AP transmission scheme is JT / JR, STA 1606 can also transmit frame 1616 to AP 1604, and STA 1608 can also transmit frame 1618 to AP 1602. The capabilities for transmitting and receiving frames 1616 and 1618 may depend on the specific multi-AP transmission scheme adopted.

[216] Figure 17 illustrates an example 1700 of a multi-AP uplink data transmission phase. The multi-AP uplink data transmission phase 1700 can be an example of the multi-AP data transmission phase 1516. As shown in Figure 17, example 1700 can include a master AP 1702 and a slave AP 1704 of a multi-AP group. Example 1700 can additionally include STAs 1706 and 1708 associated with AP 1702 and a STA 1710 associated with AP 1704.

[217] As shown in Figure 17, the multi-AP uplink data transmission phase 1700 may include frame exchanges to allow master AP 1702 to coordinate with slave AP 1704 to execute specific multi-AP transmission schemes with STAs 1706, 1708, and 1710. Multi-AP transmission schemes may include COFDMA, CTDMA, CSR, Petition 870250094447, dated 10 / 16 / 2025, pp. 253 / 332 54 / 89 CBF, JT / JR, or a combination of two or more of the previously mentioned schemes.

[218] As shown in Figure 17, master AP 1702 can start phase 1700 by transmitting a 1712 frame to AP 1704. The 1712 frame may include information related to AP 1704 (e.g., an AP 1704 identifier), synchronization information, information related to a specific multi-AP transmission scheme to be used, and / or information related to a RU for use by AP 1704 to acknowledge the 1712 frame. The 1712 frame may comprise a control frame. For example, the 1712 frame may comprise a multi-AP trigger frame.

[219] Slave AP 1704 can receive frame 1712 and can use the synchronization information to synchronize with master AP 1702. Subsequently, APs 1702 and 1704 can request uplink data transmissions from their associated STAs 1706, 1708, and 1710 using trigger frames. Specifically, AP 1702 can transmit a trigger frame 1714 to its associated STAs 1706 and 1708, and AP 1704 can transmit a trigger frame 1716 to its associated STA 1710. Depending on the multi-AP transmission scheme used, APs 1702 and 1704 can also transmit frames 1714 and 1716, respectively, to STAs on different BSSs. For example, when the multi-AP transmission scheme is JT / JR, AP 1702 can also transmit frame 1714 to STA 1710 associated with slave AP 1704, and AP 1704 can also transmit frame 1716 to STA 1706 and 1708 associated with AP 1702.The capabilities for transmitting and receiving 1714 and 1716 frames may depend on the specific multi-AP transmission scheme adopted.

[220] STAs 1706 and 1708 can respond to frame 1714, STA 1710 can respond to frame 1716. For example, STAs 1706 and 1708 can transmit frames 1718 and 1720, respectively, to AP 1702, while STA 1710 can transmit frame 1722 to AP 1704. Frames 1718, 1720 and / or 1722 can be transmitted simultaneously. Frames 1718, 1720 and Petition 870250094447, dated 10 / 16 / 2025, pp. 254 / 332 55 / 89 Frames 1722 may comprise data frames or null data frames. STAs 1706, 1708, and 1710 may also transmit frames 1718, 1720, and 1722, respectively, to APs in different BSSs, when required by the multi-AP transmission scheme used. For example, when the multi-AP transmission scheme is JT / JR, STAs 1706 and 1708 may also transmit the respective frames 1718 and 1720 to AP 1704, and STA 1710 may also transmit frame 1722 to AP 1702. The capabilities for transmitting and receiving frames 1718, 1720, and 1722 may depend on the specific multi-AP transmission scheme adopted.

[221] A non-simultaneous transmit and receive (NSTR) mobile AP MLD is a mobile AP MLD with at least one NSTR link pair. An NSTR link pair is a pair of links corresponding to STAs affiliated with an MLD for which the receiver requirements are not met on one of the links when an STA affiliated with the MLD is transmitting on the other link. Each link in such a pair is a member of the NSTR link pair. For example, if an MLD supports transmission on link 1 simultaneously with reception on link 2, but cannot support transmission on link 2 simultaneously with reception on link 1, then link 1 and link 2 are an NSTR link pair for that MLD.

[222] A transmit and receive (STR) link pair is a link pair that is not an NSTR link pair. When a link pair on which an MLD operates is an STR link pair, an STA that is affiliated with the MLD and that is operating on a first link in the STR link pair must access the wireless medium on the first link following the rules for EDCA, regardless of any activity that occurs on a second link of the STR link pair, unless explicitly indicated otherwise.

[223] All link pairs for an AP MLD that is not an NSTR mobile AP MLD and that operates on more than one link must be STR link pairs. If an AP MLD that is not an NSTR mobile AP MLD Petition 870250094447, dated 10 / 16 / 2025, pp. 255 / 332 Since 56 / 89 operates on only one link, any STR requirements and capabilities that correspond to a pair of links no longer apply.

[224] An AP affiliated with an AP MLD that has earned the right to initiate transmission of a frame from an AC on a link through the rules for EDCA may choose not to transmit any frame corresponding to that AC due to the expected interference caused by transmission on the STA operating on the other link of an NSTR link pair to which the link belongs within the intended recipient's non-AP MLD, and due to the lack of availability of an alternative frame in the queue that would not introduce the opportunity for such interference.

[225] A non-AP STA affiliated with a non-AP MLD operating on a link of an NSTR link pair that has earned the right to initiate transmission of a frame from an AC on a link through the rules for EDCA withdrawal or that is enabled by an AP, which is the holder of the TXOP, to use a portion of the TXOP obtained through the rules for triggered TXOP sharing, may choose not to transmit any frame corresponding to that AC due to the expected interference caused by the transmission on the non-AP STA operating on the other link of the NSTR link pair within the non-AP MLD and due to the lack of availability of an alternative frame in the queue that would not introduce the opportunity for such interference.

[226] A non-AP STA affiliated with a non-AP MLD or an NSTR mobile AP MLD operating on an NSTR link pair is considered to have lost media synchronization when the other STA, which is affiliated with the same MLD and operates on the NSTR link pair, transmits a PPDU, except when both STAs have completed a transmission at the same time.

[227] An STA that has lost media synchronization, as described above, due to a transmission by another STA (affiliated with the same MLD and operating on the NSTR link pair) may initiate a MediumSyncDelay timer and begin counting down from the end of that transmission, if that transmission is longer than a MediaSyncThreshold, the Petition 870250094447, dated 10 / 16 / 2025, pp. 256 / 332 57 / 89 unless your previous MediumSyncDelay timer has expired. The STA may choose not to (re)start the MediumSyncDelay timer if the broadcast event is shorter than or equal to aMediumSyncThreshold. aMediumSyncThreshold is set to 72 μs.

[228] If an STA operating on an NSTR link pair has lost media synchronization due to a transmission by another STA affiliated with the same MLD and operating on the NSTR link pair, and its previous MediumSyncDelay timer has not expired, then at the end of that transmission it must continue the previous MediumSyncDelay timer, except that the STA must update the timer value as described above if that transmission is greater than a MediaSyncThreshold.

[229] AP-assisted media synchronization recovery is a service provided by an AP MLD to assist a non-AP STA affiliated with a non-AP MLD that has lost media synchronization to transmit a frame without causing a collision with another transmission.

[230] An AP affiliated with an AP MLD with dot11AAROptionImplemented true must set the AAR support (AP assistance request) subfield in the MLD capabilities and operations subfield on a multi-link basic element that it transmits as 1; otherwise, the AP must set the AAR support subfield as 0.

[231] A non-AP STA affiliated with a non-AP MLD with dot11AAROptionImplemented that is true and that belongs to an NSTR link pair must transmit the AAR control subfield in a frame that requests an immediate response to its associated AP affiliated with an AP MLD if it has received a multi-link basic element from the AP with the AAR support subfield equal to 1 and an assisted STA that belongs to the NSTR link pair you need assistance in transmitting frames to your associated AP on the other link.

[232] The AAR control subfield transmitted by the STA must indicate the link identifier(s) of the other affiliated assistant AP(s) with Petition 870250094447, dated 10 / 16 / 2025, pp. 257 / 332 58 / 89 the same AP MLD operating on the enabled link(s) setting the corresponding bits to 1.

[233] Each of the other auxiliary APs affiliated with the AP MLD must schedule a trigger frame for transmission to the assisted non-AP STA that is associated with it and affiliated with the non-AP MLD to request a UL frame after the AP affiliated with the same AP MLD has correctly received the AAR control subfield in a frame, if it does not have frame exchanges already scheduled with another non-AP STA.

[234] A non-AP STA with dot11AAROptionImplemented that is false should not transmit a frame containing an AAR control subfield to its associated AP.

[235] A non-AP STA shall not transmit a frame containing an AAR control subfield with a value of 1 in the bit that identifies the link identifier of its associated AP.

[236] An AP shall not transmit the AAR control subfield in a frame to its associated non-AP STAs.

[237] Figure 18 illustrates an example 1800 format of an AAR control subfield of a data frame. The AAR control subfield contains a Control ID subfield and a Control Information subfield. The Control ID subfield indicates a value of 9 for AAR. The Control Information subfield contains link identifier(s) information of the assistant AP(s) affiliated with an AP MLD that are requested to assist a non-AP STA affiliated with a non-AP MLD, belonging to a non-simultaneous transmit / receive (NSTR) link pair, to regain its media synchronization. The assistant AP link ID bitmap subfield in the AAR control subfield indicates the link(s) associated with the link identifier(s) of the assistant AP(s) affiliated with an AP MLD.

[238] Figure 19 illustrates a 1900 example of an existing AP-assisted media synchronization recovery procedure. As Petition 870250094447, dated 10 / 16 / 2025, pp. 258 / 332 59 / 89 shown in Figure 19, example 1900 includes an AP 1902 and a STA 1904. AP 1902 may comprise an AP MLD comprising affiliated AP STAs 1902-1, 1902-2, and 1902-3. STA 1904 may comprise a non-AP MLD comprising affiliated non-AP STAs 1904-1, 1904-2, and 1904-3. In example 1900, for STA 1904, link 1 and link 2 are an NSTR link pair, link 1 and link 3 are an NSTR link pair, and link 2 and link 3 are an STR link pair. In example 1900, the AP STAs 1902-2 and 1902-3 are requested to assist the non-AP STAs 1904-2 and 1904-3, which have lost media synchronization, in transmitting a frame, respectively.

[239] As shown in Figure 19, example 1900 can begin with Non-AP STA 1904-1 transmitting a 1910 data frame to AP STA 19021. Because links 1 and 2 and links 1 and 3 are NSTR link pairs for STA 1904, non-AP STAs 1904-2 and 1904-3 lose medium synchronization due to the transmission of the 1910 data frame. Non-AP STAs 1904-2 and 1904-3 each start a MediumSyncDelay timer at the end of the transmission of the 1910 data frame by non-AP STA 1904-1. In order to transmit on link 2 while the MediumSyncDelay timer is running, the non-AP 1904-2 STA needs to receive a frame on link 2, which allows it to regain media synchronization on link 2. Similarly, in order to transmit on link 3 while the MediumSyncDelay timer is running, the non-AP 1904-3 STA needs to receive a frame on link 3, which allows it to regain media synchronization on link 3.

[240] In one example, data frame 1910 may comprise an AP Assistance Request (AAR) requesting that AP STAs 1902-2 and 1902-3 provide media synchronization recovery assistance to non-AP STAs 1904-2 and 1904-3, respectively. That is, data frame 1910 may request that AP STAs 1902-2 and 1902-3 assist non-AP STAs 1904-2 and 1904-3, respectively, in recovering media synchronization lost due to the transmission of data frame 1910 (transmitting the respective frames on links 2 and 3 to non-AP STAs 1904-2 and 1904-3, Petition 870250094447, dated 10 / 16 / 2025, pp. 259 / 332 60 / 89 respectively). In one implementation, the bits corresponding to link 2 and link 3 in an AAR control subfield of the AAR are set to 1.

[241] After the AP 1902-1 STA receives the 1910 data frame, the AP STAs 1902-2 and 1902-3 transmit trigger frames 1912-1 and 1912-2 to non-AP STAs 1904-2 and 1904-3, respectively, requesting uplink frame transmissions from non-AP STAs 1904-2 and 1904-3. Upon receiving trigger frames 1912-1 and 1912-2, respectively, non-AP STAs 1904-2 and 1904-3 regain media synchronization and can subsequently transmit their respective data frames 1914-1 and 1914-2 to AP STAs 1902-2 and 1902-3, respectively. Since the 1912-1 and 1912-2 trigger frames allow non-AP STAs 1904-2 and 1904-3 to regain medium synchronization, non-AP STAs 1904-2 and 1904-3 can transmit their respective 1914-1 and 1914-2 data frames without waiting for the MediumSyncDelay timer to expire.

[242] Figure 20 illustrates another example 2000 of the AP-assisted media synchronization recovery procedure described in Figure 19. As shown in Figure 20, example 2000 includes an AP 2002 and a STA 2004. AP 2002 may comprise an AP MLD comprising affiliated AP STAs 2002-1 and 1902-2. STA 2004 may comprise a non-AP MLD comprising affiliated non-AP STAs 2004-1 and 2004-2. In example 2000, for STA 2004, link 1 and link 2 are an NSTR link pair. In example 2000, AP STA 2002-2 is requested to assist non-AP STA 1904-2, which has lost media synchronization, in transmitting a frame.

[243] As shown in Figure 20, example 2000 can start with STA non-AP 2004-1 transmitting a data frame 2010 to STA non-AP 2002-1 via link 1. Because links 1 and 2 are NSTR link pairs for STA 2004, STA non-AP 2004-2 loses medium synchronization due to the transmission of data frame 2010. STA non-AP 2004-2 initiates a MediumSyncDelay timer for link 2 at the end of the transmission. Petition 870250094447, dated 10 / 16 / 2025, pp. 260 / 332 61 / 89 data frame 2010 by STA non-AP 2004-1 via link 1. In order to transmit on link 2, while the MediumSyncDelay timer is running, the STA non-AP 1204-2 needs to receive a frame on link 2, which allows it to regain medium synchronization on link 2.

[244] In one example, the 2010 data frame may comprise a The AAR is requesting that the AP 2002-2 STA provide media synchronization recovery assistance to the non-AP 2004-2 STA. That is, data frame 2010 can request that the AP 2002-2 STA assist the non-AP 2004-2 STA in recovering lost media synchronization due to the transmission of data frame 2010 (transmitting a frame on link 2 to the non-AP 2004-2 STA). In one implementation, a bit corresponding to link 2 in an AAR control subfield of the AAR is set to 1.

[245] In example 2000, AP 2002 suffers from OBSS interference on link 1 at the time of transmission of data frame 2010. The OBSS interference may be hidden from STA 2004. Due to the OBSS interference, AP 2002 may fail to receive data frame 2010 through link 1.

[246] In one example, AP 2002 may not transmit a block acknowledgment (BA) in response to data frame 2010. In another example, AP 2002 may not transmit, via link 2, a frame (e.g., trigger frame) to STA 2004 to assist non-AP STA 2004-2 in regaining media synchronization on link 2. Consequently, non-AP STA 2004-2 may not be able to regain media synchronization on link 2 while the MediumSyncDelay timer is running and may have to wait for the MediumSyncDelay timer to expire in order to transmit a frame via link 2 to AP STA 2002-2. In this way, traffic for transmission on non-AP STA 2004-2 may be delayed.

[247] The embodiments of the present disclosure, as further described below, address the problems described above of the existing AP-assisted media synchronization recovery procedure. In one embodiment, a first AP can receive a first frame transmitted by Petition 870250094447, dated 10 / 16 / 2025, pp. 261 / 332 62 / 89 a STA to a second AP comprising an AP Assistance Request (AAR) for the second AP. The first frame may be transmitted on a first link and the AAR may be to a second link. Based on the first AP not receiving an acknowledgment frame from the second AP for the STA in response to the first frame, the first AP may transmit a second frame to the second AP informing the second AP about the AAR comprised in the first frame. Based on the receipt of the second frame from the first AP, the second AP may transmit a third frame to the STA, allowing the STA to regain media synchronization on the second link. In another embodiment, based on the first AP not receiving an acknowledgment frame from the second AP for the STA in response to the first frame, the first AP transmits a second frame to the STA. The first frame allows the STA to regain media synchronization on the second link.

[248] Figure 21 illustrates an example 2100 of an AP-assisted media synchronization recovery procedure according to a modality. Example 2100 is provided for illustrative purposes only and is not limiting. As shown in Figure 21, example 2100 includes APs 2102 and an AP 2104 and a STA 2106. AP 2102 and / or AP 2104 may comprise an AP MLD. STA 2106 may comprise a non-AP MLD. In one example, AP 2102 includes an affiliated AP STA 2102-1 and an affiliated AP STA 2102-2. In one example, AP 2104 includes an affiliated AP STA 2104-1 and an affiliated AP STA 2104-2. In one example, STA 2106 includes an affiliated non-AP STA 2106-1 and an affiliated non-AP STA 2106-2. In another example, AP STA 2102-1, AP STA 2104-1, and non-AP STA 2106-1 operate on a first link (link 1). In another example, non-AP STA 2106-1 is associated with AP STA 2102-1. In another example, AP STA 2102-2, AP STA 2104-2, and non-AP STA 2106-2 operate on a second link (link 2).In one example, the non-AP 2106-2 STA is associated with the AP 2102-2 STA.

[249] In one embodiment, link 1 and link 2 form a pair of NSTR links in STA 2106. Petition 870250094447, dated 10 / 16 / 2025, pp. 262 / 332 63 / 89

[250] In one embodiment, the AP STAs 2102-1 and 2104-1 belong to different sets of basic services (BSSs). In another embodiment, the AP STAs 2102-2 and 2104-2 belong to different BSSs.

[251] In one embodiment, AP 2104 transmits to AP 2102, via link 1 or link 2, a first indication of support by AP 2104 of an assisted media synchronization recovery capability between APs. In another embodiment, AP 2104 receives from AP 2102, via link 1 or link 2, a second indication of support by AP 2102 of the assisted media synchronization recovery capability between APs.

[252] In example 2100, it is assumed that both AP 2102 and AP 2104 support assisted media synchronization recovery capability between APs. In one example, support for assisted media synchronization recovery capability between APs allows AP 2104 to transmit or receive frames (such as frame 2114 described below) to AP 2104. In another example, support for assisted media synchronization recovery capability between APs allows AP 2104 to receive and process frames (such as frame 2112 described below) transmitted by STA 2106 associated with AP 2102. In yet another example, support for assisted media synchronization recovery capability between APs allows AP 2104 to transmit frames (such as frame 2314 described) to STA 2106 associated with AP 2102.

[253] In one example, the STA of AP 2102-1 and the STA of AP 2104-1 form a multi-AP group. In another example, the STA of AP 2102-2 and the STA of AP 2104-2 form a multi-AP group.

[254] As shown in Figure 21, example 2100 can start with STA non-AP 2106-1 transmitting a first frame 2112 to STA non-AP 2102-1 via link 1. Because links 1 and 2 are NSTR link pairs for STA 2106, STA non-AP 2106-2 loses medium synchronization due to the transmission of the first frame 2112. STA non-AP 2106-2 starts a MediumSyncDelay timer at the end of the transmission of the first data frame 2112 by STA non-AP 2106-1. In order to be able to transmit on link 2, Petition 870250094447, dated 10 / 16 / 2025, pp. 263 / 332 64 / 89 while the MediumSyncDelay timer is running, the STA non-AP 2106-2 needs to receive a frame on link 2, which allows it to recover mid-sync on link 2.

[255] In one embodiment, the first frame 2112 comprises an AAR to AP 2102 for link 2. That is, the first frame 2112 requests that AP 2102 provide media synchronization recovery assistance to STA 2106 for link 2. In an example, the first frame 2112 may comprise an AAR requesting that the STA of AP 2102-2 provide media synchronization recovery assistance to the non-AP STA 2106-2. That is, the first frame 2112 may request that the STA of AP 2102-2 assist the non-AP STA 2106-2 in recovering media synchronization lost due to the transmission of the first frame 2112 (by transmitting a frame on link 2 to the non-AP STA 2106-2). In one implementation, a bit corresponding to link 2 in an AAR control subfield of the AAR is set to 1. In one embodiment, the first 2112 frame may comprise a data frame.

[256] In example 2100, AP 2102 suffers from OBSS interference on link 1 at the time of transmission of the first frame 2112 by STA 2106. The OBSS interference may be hidden from STA 2106. Due to the OBSS interference, AP 2102 may fail to receive the first frame 2112 through link 1. In one mode, AP 2104 receives the first frame 2112 through link 1.

[257] In one example, AP 2102 may not transmit a BA in response to the first frame 2112. In another example, AP 2102 may not transmit, via link 2, a frame (e.g., trigger frame) to STA 2106 to assist the non-AP 2106-2 STA in regaining media synchronization on link 2.

[258] In one embodiment, based on AP 2104 not receiving (not hearing) an acknowledgment frame (e.g., BA frame) from AP 2102 for STA 2106, in response to frame 2112, AP 2104 transmits to AP 2102 a second frame 2114 informing AP 2102 about the AAR included in Petition 870250094447, dated 10 / 16 / 2025, pp. 264 / 332 65 / 89 first frame 2112. In one embodiment, the transmission of the second frame 2114 comprises the transmission of frame 2114 through link 1 or link 2. In example 2100, frame 2114 is transmitted through link 2, as shown in Figure 21.

[259] In one embodiment, the second frame 2114 comprises an indication of link 2. In another embodiment, the second frame 2114 comprises an indication of STA 2106. The second frame 2114 may be a management frame. For example, frame 2114 may be an action frame. The second frame 2114 may be a control frame. For example, frame 2114 may be a trigger frame. The second frame 2114 may be a data frame. For example, frame 2114 may be a QoS null frame.

[260] In one embodiment, AP 2102 transmits a third frame 2116, through link 2, to STA 2106 in response to receiving the second frame 2114. The third frame 2116 allows STA 2106 to regain medium synchronization on link 2, and STA 2106 may not need to wait for the MediumSyncDelay timer to expire before it can transmit a frame through link 2. The third frame 2116 can be a control frame or a management frame. In one example, the third frame 2116 can be a trigger frame that requests STA 2106 to transmit a fourth frame 2118 through link 2.

[261] Figure 22 illustrates another example 2200 of an AP-assisted media synchronization recovery procedure according to a modality. Example 2200 is provided for illustrative purposes only and is not limiting. As shown in Figure 22, example 2200 includes APs 2202 and an AP 2204 and a STA 2206. AP 2202 and / or AP 2204 may comprise an AP MLD. STA 2206 may comprise a non-AP MLD. In one example, AP 2202 includes an affiliated AP STA 2202-1 and an affiliated AP STA 2202-2. In one example, AP 2204 includes an affiliated AP STA 2204-1 and an affiliated AP STA 2204-2. In one example, STA 2206 includes a non-AP affiliated STA 2206. Petition 870250094447, dated 10 / 16 / 2025, pp. 265 / 332 66 / 89 and a non-AP affiliated STA 2206-2. In one example, AP STA 2202-1, AP STA 2204-1, and non-AP STA 2206-1 operate on a first link (link 1). In one example, non-AP STA 2206-1 is associated with AP STA 2202-1. In another example, AP STA 2202-2, AP STA 2204-2, and non-AP STA 2206-2 operate on a second link (link 2). In one example, non-AP STA 2206-2 is associated with AP STA 2202-2.

[262] In one embodiment, link 1 and link 2 form a pair of NSTR links in STA 2206.

[263] In one embodiment, STAs of AP 2202-1 and 2204-1 belong to different sets of basic services (BSSs). In another embodiment, STAs of AP 2202-2 and 2204-2 belong to different BSSs.

[264] In one embodiment, AP 2204 transmits to AP 2202, via link 1 or link 2, a first indication of support by AP 2204 of an assisted media synchronization recovery capability between APs. In another embodiment, AP 2204 receives from AP 2202, via link 1 or link 2, a second indication of support by AP 2202 of the assisted media synchronization recovery capability between APs. It is assumed, in example 2200, that both AP 2202 and AP 2204 support the assisted media synchronization recovery capability between APs.

[265] In example 2200, it is assumed that both AP 2202 and AP 2204 support assisted media synchronization recovery capability between APs. In one example, support for assisted media synchronization recovery capability between APs allows AP 2204 to transmit or receive frames (such as frame 2214 described below) to AP 2204. In another example, support for assisted media synchronization recovery capability between APs allows AP 2204 to receive and process frames (such as frame 2212 described below) transmitted by STA 2206 associated with AP 2202. In yet another example, support for assisted media synchronization recovery capability between APs allows AP 2204 to transmit frames (such as frame 2314 described below) to STA 2206 associated with AP 2202. Petition 870250094447, dated 10 / 16 / 2025, pp. 266 / 332 67 / 89

[266] In one example, the STA of AP 2202-1 and the STA of AP 2204-1 form a multi-AP group. In another example, the STA of AP 2202-2 and the STA of AP 2204-2 form a multi-AP group.

[267] As shown in Figure 22, example 2200 can begin with STA non-AP 2206-1 transmits a first frame 2212 to STA non-AP 2206-1 via link 1. Because links 1 and 2 are NSTR-to-STA 2206 link pairs, STA non-AP 2206-2 loses media synchronization due to the transmission of the first frame 2212. STA non-AP 2206-2 starts a MediumSyncDelay timer at the end of the transmission of the first data frame 2212 by STA non-AP 2206-1. In order to transmit on link 2 while the MediumSyncDelay timer is running, STA non-AP 2206-2 needs to receive a frame on link 2, which allows it to regain media synchronization on link 2.

[268] In one embodiment, the first frame 2212 comprises an AAR to AP 2202 for link 2. That is, the first frame 2212 requests that AP 2202 provide media synchronization recovery assistance to STA 2206 for link 2. In an example, the first frame 2212 may comprise an AAR requesting that the STA of AP 2202-2 provide media synchronization recovery assistance to the non-AP STA 2206-2. That is, the first frame 2212 may request that the STA of AP 2202-2 assist the non-AP STA 2206-2 in recovering media synchronization lost due to the transmission of the first frame 2212 (by transmitting a frame on link 2 to the non-AP STA 2206-2). In one implementation, a bit corresponding to link 2 in an AAR control subfield of the AAR is set to 1. In one embodiment, the first 2212 frame may comprise a data frame.

[269] In example 2200, AP 2202 suffers from OBSS interference on link 1 at the time of transmission of the first frame 2212 by STA 2206. The OBSS interference may be hidden from STA 2206. Due to the OBSS interference, AP 2202 may fail to receive the first frame. Petition 870250094447, dated 10 / 16 / 2025, pp. 267 / 332 68 / 89 2212 via link 1. In one mode, AP 2204 receives the first frame 2212 via link 1.

[270] In one example, AP 2202 may not transmit a BA in response to the first frame 2212. In another example, AP 2202 may not transmit, via link 2, a frame (e.g., trigger frame) to STA 2206 to assist the non-AP STA 2206-2 in regaining media synchronization on link 2.

[271] In one embodiment, based on AP 2204 not receiving (not hearing) an acknowledgment frame (e.g., BA frame) from AP 2202 for STA 2206, in response to frame 2212, AP 2204 transmits to AP 2202 a second frame 2214 informing AP 2202 about the AAR comprised in the first frame 2212. In one embodiment, the transmission of the second frame 2214 comprises the transmission of frame 2214 through link 1 or link 2. In example 2200, frame 2214 is transmitted through link 1, as shown in Figure 22. The transmission of frame 2214 through link 1 can provide diversity between multiple links to improve transmission reliability.

[272] In one embodiment, the second frame 2214 comprises a link 2 indication. In another embodiment, the second frame 2214 comprises a STA 2206 indication. The second frame 2214 may be a management frame. For example, frame 2214 may be an action frame. The second frame 2214 may be a control frame. For example, the first frame 2214 may be a first trigger frame. The second frame 2214 may be a data frame. For example, frame 2214 may be a QoS null frame.

[273] In one embodiment, AP 2202 transmits a third frame 2216, through link 2, to STA 2206 in response to receiving the second frame 2214. The third frame 2216 allows STA 2206 to regain medium synchronization on link 2 and STA 2206 may not need to wait for the MediumSyncDelay timer to expire before it can transmit a Petition 870250094447, dated 10 / 16 / 2025, pp. 268 / 332 Frame 69 / 89 is transmitted through link 2. The third frame, 2216, can be a control frame or a management frame. In one example, the third frame, 2216, could be a trigger frame requesting that STA 2206 transmit a fourth frame, 2218, through link 2.

[274] Figure 23 illustrates another example 2300 of an AP-assisted media synchronization recovery procedure according to a modality. Example 2300 is provided for illustrative purposes only and is not limiting. As shown in Figure 23, example 2300 includes APs 2302 and an AP 2304 and a STA 2306. AP 2302 and / or AP 2304 may comprise an AP MLD. STA 2306 may comprise a non-AP MLD. In one example, AP 2302 includes an affiliated AP STA 2302-1 and an affiliated AP STA 2302-2. In one example, AP 2304 includes an affiliated AP STA 2304-1 and an affiliated AP STA 2304-2. In one example, STA 2306 includes an affiliated non-AP STA 23061 and an affiliated non-AP STA 2306-2. In another example, AP STA 2302-1, AP STA 2304-1, and non-AP STA 2306-1 operate on a first link (link 1). In another example, non-AP STA 2306-1 is associated with AP STA 2302-1. In another example, AP STA 2302-2, AP STA 2304-2, and non-AP STA 2306-2 operate on a second link (link 2).In one example, the non-AP STA 2306-2 is associated with the AP STA 2302-2.

[275] In one embodiment, link 1 and link 2 form a pair of NSTR links in STA 2306.

[276] In one embodiment, STAs of AP 2302-1 and 2304-1 belong to different sets of basic services (BSSs). In another embodiment, STAs of AP 2302-2 and 2304-2 belong to different BSSs.

[277] In one embodiment, AP 2304 transmits to AP 2302, via link 1 or link 2, a first indication of support by AP 2304 of an assisted media synchronization recovery capability between APs. In another embodiment, AP 2304 receives from AP 2302, via link 1 or link 2, a second indication of support by AP 2302 of the assisted media synchronization recovery capability between APs. It is assumed, in Petition 870250094447, dated 10 / 16 / 2025, pp. 269 / 332 70 / 89 example 2300, that both AP 2302 and AP 2304 support assisted media synchronization recovery capability between APs.

[278] In example 2300, it is assumed that both AP 2302 and AP 2304 support assisted media synchronization recovery capability between APs. In one example, support for assisted media synchronization recovery capability between APs allows AP 2304 to transmit or receive frames (such as frame 2314 described below) to AP 2304. In another example, support for assisted media synchronization recovery capability between APs allows AP 2304 to receive and process frames (such as frame 2312 described below) transmitted by STA 2306 associated with AP 2302. In yet another example, support for assisted media synchronization recovery capability between APs allows AP 2304 to transmit frames (such as frame 2314 described below) to STA 2306 associated with AP 2302.

[279] In one example, the STA of AP 2302-1 and the STA of AP 2304-1 form a multi-AP group. In another example, the STA of AP 2302-2 and the STA of AP 2304-2 form a multi-AP group.

[280] As shown in Figure 23, example 2300 can begin with STA non-AP 2306-1 transmits a first 2312 frame to STA non-AP 2302-1 via link 1. Because links 1 and 2 are NSTR-to-STA 2306 link pairs, STA non-AP 2306-2 loses media synchronization due to the transmission of the first 2312 frame. STA non-AP 2306-2 starts a MediumSyncDelay timer at the end of the transmission of the first 2312 data frame by STA non-AP 2306-1. In order to transmit on link 2 while the MediumSyncDelay timer is running, STA non-AP 2306-2 needs to receive a frame on link 2, which allows it to regain media synchronization on link 2.

[281] In one embodiment, the first frame 2312 comprises an AAR to AP 2302 for link 2. That is, the first frame 2312 requests that AP 2302 provide media synchronization recovery assistance to STA 2306 for link 2. In one example, the first frame 2312 might Petition 870250094447, dated 10 / 16 / 2025, pp. 270 / 332 71 / 89 understand an AAR requesting that the AP 2302-2 STA provide media synchronization recovery assistance to the non-AP 2306-2 STA. That is, the first frame 2312 can request that the AP 2302-2 STA assist the non-AP 2306-2 STA in recovering media synchronization lost due to the transmission of the first frame 2312 (transmitting a frame on link 2 to the non-AP 2306-2 STA). In one implementation, a bit corresponding to link 2 in an AAR control subfield of the AAR is set to 1. In one embodiment, the first frame 2312 can understand a data frame.

[282] In example 2300, AP 2302 suffers from OBSS interference on link 1 at the time of transmission of the first frame 2312 by STA 2306. The OBSS interference may be hidden from STA 2306. Due to the OBSS interference, AP 2302 may fail to receive the first frame 2312 through link 1. In one mode, AP 2304 receives the first frame 2212 through link 1.

[283] In one example, AP 2302 may not transmit a BA in response to the first frame 2312. In another example, AP 2302 may not transmit, via link 2, a frame (e.g., trigger frame) to STA 2306 to assist STA non-AP 2306-2 in regaining media synchronization on link 2.

[284] In one embodiment, based on AP 2304 not receiving (not listening to) an acknowledgment frame (e.g., BA frame) from AP 2302 to STA 2306 in response to frame 2312, AP 2104 transmits a second frame 2314 to STA 2306. In one embodiment, the transmission of the second frame 2314 comprises the transmission of frame 2314 through link 2.

[285] In one embodiment, the second frame 2314 allows STA 2306 to regain medium synchronization on link 2, and STA 2306 may not need to wait for the MediumSyncDelay timer to expire before it can transmit a frame across link 2. In one embodiment, the second frame 2314 comprises an indication from STA 2306. The second frame 2314 may be a management frame. For example, frame 2314 may be Petition 870250094447, dated 10 / 16 / 2025, pp. 271 / 332 72 / 89 an action frame. The second frame 2314 can be a control frame. For example, the first frame 2314 can be a first trigger frame. In one mode, the second frame 2314 informs STA 2306 to transmit a fourth frame 2316, through link 2, to AP 2302.

[286] In one embodiment, frame 2114 described in Figure 21, frame Table 2214 described in Figure 22 and table 2314 described in Figure 23 can be management charts, such as action charts.

[287] Figure 24 illustrates an example 2400 action frame that can be used according to the modalities. For example, the 2400 action frame can be a modality of the 2114, 2214, and / or 2314 frames. In one example, the 2400 action frame can be a public action frame. In one modality, the 2400 action frame can include information indicating assistance between APs for media synchronization recovery. In one modality, the information indicating assistance between APs for media synchronization recovery includes an indication of the link for which media synchronization recovery is requested and an indication of the requesting STA.

[288] As shown in Figure 24, action frame 2400 may include an action field 2402. In one embodiment, action field 2402 may include a category subfield 2410 to indicate assistance between APs. In one example, action field 2402 may include an action detail field 2412. In one embodiment, the action detail field 2412 may include information indicating assistance between APs for media synchronization recovery. In one example, action detail field 2412 may include an optional subfield 2414 for indicating the link for which media synchronization recovery is requested and an optional subfield 2416 for indicating the requesting STA. For example, the link indication may be a link identifier (ID). For example, the requesting STA indication may be a non-AP MLD association identifier (AID). In one example, subfields 2414 and 2416 are present when the frame of Petition 870250094447, dated 10 / 16 / 2025, pp. 272 / 332 73 / 89 Action 2400 is transmitted by one AP to another AP. In another example, when the Action 2400 frame is transmitted by an AP to an unassociated STA, subfields 2414 and 2416 may include reserved bits.

[289] In one embodiment, frame 2114 described in Figure 21, frame 2214 described in Figure 22 can be data frames, such as QoS null frames.

[290] Figure 25 illustrates an example QoS 2500 null frame that can be used according to the modes. For example, the QoS 2500 null frame can be a mode of frames 2114 and 2214. In one mode, the QoS 2500 null frame can include information indicating assistance between APs for media synchronization recovery. In one mode, the information indicating assistance between APs for media synchronization recovery includes an indication of the link for which media synchronization recovery is requested and an indication of the requesting STA.

[291] As illustrated by Figure 25, the QoS 2500 null frame may include an HT 2502 control field. In one embodiment, the HT 2502 control field may include information indicating inter-AP assistance for media synchronization recovery. In one embodiment, the information indicating inter-AP assistance for media synchronization recovery includes an indication of the link for which media synchronization recovery is requested and an indication of the requesting STA. In one example, the HT 2502 control field may include an A-Control subfield. The A-Control subfield may include a 2510 control list subfield including one or more control subfields. In one embodiment, a control subfield may include information indicating inter-AP assistance for media synchronization recovery. For example, the control subfield may be an inter-AP assistance A-control subfield.In one example, a control subfield includes a subfield 2520 for AP-to-AP assistance control ID and a control information subfield 2522. The control information subfield 2522 may include a subfield 2524 for link indication. Petition 870250094447, dated 10 / 16 / 2025, pp. 273 / 332 74 / 89 which means the recovery of media synchronization is requested and a subfield 2526 for indicating the requesting STA.

[292] In one embodiment, frame 2114 described in Figure 21, frame Frame 2214 described in Figure 22 and frame 2314 described in Figure 23 can be control frames, such as trigger frames.

[293] Figure 26 illustrates an example 2600 trigger frame that can be used according to the modes. For example, the 2600 trigger frame can be a mode of the 2114 or 2214 frame. In one mode, the 2600 trigger frame can include information indicating assistance between APs for media synchronization recovery. In one mode, the information indicating assistance between APs for media synchronization recovery includes an indication of a receiving AP, an indication of the link for which media synchronization recovery is requested, and an indication of the requesting STA.

[294] As shown in Figure 26, the trigger frame 2600 may include a common information field 2602 and a user information list field 2604.

[295] In one embodiment, the 2600 trigger frame can be used by a first AP to inform a second AP about an inter-AP assistance request. In one embodiment, the 2604 user information list field of the 2600 trigger frame can include information indicating an inter-AP assistance request for media synchronization recovery. In one example, the 2604 user information list field can include a 2610 field. For example, the 2610 field can be an inter-AP assistance information field.

[296] In one embodiment, as shown in Figure 26, the common information field 2602 may include a field flag field 2606 indicating the presence of field 2610 used in the user information list field 2604. In one embodiment, the common information field 2602 may include information indicating assistance between APs. The format of Petition 870250094447, dated 10 / 16 / 2025, pp. 274 / 332 75 / 89 subfields that carry the information in the common information field 2602 may be similar to field 2610 in the user information list field 2604.

[297] In one embodiment, field 2610 may include a subfield 2612 for the indication of the second AP, a subfield 2614 for the indication of the link for which media synchronization recovery is requested, and a subfield 2616 for the indication of the requesting STA. For example, the indication of the second AP may be an association identifier (AID) of the second AP. For example, the indication of the link may be a link identifier (ID). For example, the indication of the requesting STA may be an AID of the requesting STA.

[298] Figure 27 illustrates another example 2700 trigger frame that can be used according to the modes. For example, the 2700 trigger frame can be a mode of the 2314 frame. In one mode, the 2700 trigger frame can be used by a first AP to provide media synchronization recovery for an STA. The STA can be an STA that is not associated with the first AP. In one mode, the 2700 trigger frame can include information indicating assistance between APs for media synchronization recovery. In one mode, the information indicating assistance between APs for media synchronization recovery includes an indication of a recipient of a fourth frame from the STA. The fourth frame can be an immediate uplink transmission in response to the 2700 trigger frame. The recipient can be a second AP with which the STA is associated.

[299] As shown in Figure 27, the trigger frame 2700 may include a common information field 2702 and a user information list field 2704. The user information list field 2704 may include one or more user information fields 2710.

[300] In one embodiment, trigger frame 2700 can be used to trigger the STA to transmit a fourth frame. In one embodiment, the user information list field 2704 of trigger frame 2700 can include the Petition 870250094447, dated 10 / 16 / 2025, pp. 275 / 332 76 / 89 information indicating an assistance between APs for media synchronization recovery. In one example, a user information field 2710 might include a subfield 2712 indicating the recipient of the fourth frame from the STA. For example, subfield 2712 could be a flag value. In one implementation, subfield 2712 could be set to 0 to indicate the trigger frame transmitter 2700 as the recipient of the fourth frame, and it could be set to 1 to indicate the second AP as the recipient of the fourth frame.

[301] In one embodiment, as shown in Figure 27, the common information field 2702 may include a field flag field 2706 indicating the presence of field 2710 used in the user information list field 2702. In one embodiment, the common information field 2702 may include information indicating assistance between APs.

[302] As would be understood by one skilled in the art based on the teachings in the present invention, the embodiments described by the examples above can be readily extended to cases including more than two APs.

[303] Figure 28 illustrates an example 2800 process according to an embodiment. The example 2800 process is provided for illustrative purposes only and is not limiting of embodiments. The 2800 process can be performed by a first AP.

[304] As shown in Figure 28, process 2800 begins at step 2802, which includes receiving, by the first AP, a first frame, transmitted by a STA to a second AP, which comprises an AP assistance request (AAR) for the second AP. In one embodiment, the STA is associated with the second AP, but not the first AP.

[305] In one embodiment, receiving the first frame involves receiving the first frame through a first link. In one embodiment, the AAR requests that the second AP transmit a third frame, through a second link, to the STA. In one embodiment, the first link and the second link form an NSTR link pair on the STA. In one example, the first link Petition 870250094447, dated 10 / 16 / 2025, pp. 276 / 332 77 / 89 may comprise one of the 2.4 GHz band, one of the 5 GHz band, one of the 6 GHz band, or one of the future bands to be defined. Similarly, the second link may comprise one of the 2.4 GHz band, one of the 5 GHz band, one of the 6 GHz band, or one of the future bands to be defined, with the second link being different from the first link.

[306] In step 2804, process 2800 includes, based on the first AP not receiving an acknowledgment frame from the second AP for the STA in response to the first frame, transmitting, through the first AP to the second AP, a second frame informing the second AP about the request contained in the first frame.

[307] In one embodiment, the transmission of the second frame comprises transmitting the second frame through the first link or the second link. In one embodiment, the second frame assists the STA in regaining media synchronization on the second link. In one embodiment, the second frame comprises an indication from the second link. In one embodiment, the second frame comprises an indication from the STA. In one embodiment, the second AP transmits a third frame, through the second link, to the STA in response to the second frame.

[308] In one embodiment, the second frame comprises a management frame. In one embodiment, the management frame comprises an action frame which comprises an action field indicating the second link and the STA.

[309] In one embodiment, the second frame comprises a control frame. In one embodiment, the control frame comprises a trigger frame which comprises a user information list field indicating the second link and the STA.

[310] In one embodiment, the second frame comprises a data frame. In one embodiment, the data frame comprises a QoS null frame comprising a high-throughput (HT) control field indicating the second link and the STA. Petition 870250094447, dated 10 / 16 / 2025, pp. 277 / 332 78 / 89

[311] In one embodiment, the first AP transmits to the second AP a first indication of support, by the first AP, of an assisted media synchronization recovery capability between APs. In another embodiment, the first AP receives from the second AP, a second indication of support by the second AP of the assisted media synchronization recovery capability between APs.

[312] In one modality, the first AP and the second AP form a multi-AP group.

[313] In one embodiment, the first AP, the second AP or the STA comprises a multi-link device (MLD).

[314] Figure 29 illustrates an example 2900 process according to an embodiment. The example 2900 process is provided for illustrative purposes only and is not limiting of embodiments. The 2900 process can be performed by a first AP.

[315] As shown in Figure 29, process 2900 begins at step 2902, which includes receiving, by the first AP from a second AP, a first frame informing the first AP about an AP Assistance Request (AAR) for the first AP transmitted by a STA. The STA may be associated with the first AP, but not the second AP.

[316] In one embodiment, receiving the first frame comprises receiving the first frame through a first link or a second link. In one embodiment, the first frame informs the first AP about the AAR operating on the second link. In one embodiment, the first link and the second link form an NSTR link pair in the STA. In one example, the first link may comprise one of a 2.4 GHz band, a 5 GHz band, a 6 GHz band, or a future band to be defined. Similarly, the second link may comprise one of the 2.4 GHz band, the 5 GHz band, the 6 GHz band, or a future band to be defined, with the second link being different from the first link. Petition 870250094447, dated 10 / 16 / 2025, pp. 278 / 332 79 / 89

[317] In one mode, the AAR requests that the first AP transmit the second frame, through the second link, to the STA. In one mode, the first frame assists the STA in regaining media synchronization on the second link. In one mode, the first frame comprises an indication from the second link. In one mode, the first frame comprises an indication from the STA.

[318] In one embodiment, the first frame comprises a management frame. In one embodiment, the management frame comprises an action frame which comprises an action field indicating the second link and the STA.

[319] In one embodiment, the first frame comprises a control frame. In one embodiment, the control frame comprises a trigger frame which comprises a user information list field indicating the second link and the STA.

[320] In one embodiment, the first frame comprises a data frame. In one embodiment, the data frame comprises a QoS null frame comprising a high-throughput (HT) control field indicating the second link and the STA.

[321] In step 2904, process 2900 includes, based on the receipt of the first frame, transmitting, by the first AP to the STA, a second frame.

[322] In one embodiment, the transmission of the second frame comprises the transmission of the second frame through the second link. In one embodiment, the first AP transmits a second frame, through the second link, to the STA in response to the first frame.

[323] In one embodiment, the first AP transmits to the second AP a first indication of support, by the first AP, of an assisted media synchronization recovery capability between APs. In another embodiment, the first AP receives from the second AP, a second indication of support by the second AP of the assisted media synchronization recovery capability between APs. Petition 870250094447, dated 10 / 16 / 2025, pp. 279 / 332 80 / 89

[324] In one modality, the first AP and the second AP form a multi-AP group.

[325] In one embodiment, the first AP, the second AP or the STA comprises a multi-link device (MLD).

[326] Figure 30 illustrates an example 3000 process according to one embodiment. The example 3000 process is provided for illustrative purposes only and is not limiting of embodiments. The 3000 process can be performed by a first AP.

[327] As shown in Figure 30, process 3000 begins at step 3002, which includes receiving, by the first AP, a first frame, transmitted by a STA to a second AP, which comprises an AP Assistance Request (AAR) for the second AP. The STA may be associated with the second AP, but not the first AP.

[328] In one embodiment, receiving the first frame involves receiving the first frame over a first link. In one embodiment, the AAR requests that the second AP transmit a third frame, over a second link, to the STA. In one embodiment, the first link and the second link form an NSTR link pair on the STA. In one example, the first link may comprise one of the 2.4 GHz band, one of the 5 GHz band, one of the 6 GHz band, or one of the future bands to be defined. Similarly, the second link may comprise one of the 2.4 GHz band, one of the 5 GHz band, one of the 6 GHz band, or one of the future bands to be defined, with the second link being different from the first link.

[329] In step 3004, process 3000 includes, based on the first AP not receiving an acknowledgment frame from the second AP for the STA in response to the first frame, transmitting, by the first AP to the second AP, a second frame.

[330] In one embodiment, the transmission of the second frame comprises the transmission of the second frame over a second link. In one embodiment, the second frame assists the STA in regaining synchronization of Petition 870250094447, dated 10 / 16 / 2025, pp. 280 / 332 81 / 89 middle on the second link. In one mode, the second frame comprises an indication from the STA. In another mode, the second frame informs the STA to transmit a fourth frame, through the second link, to the second AP.

[331] In one embodiment, the second frame comprises a management frame. In one embodiment, the management frame comprises an action frame which comprises a field of action indicating the STA.

[332] In one embodiment, the second frame comprises a control frame. In one embodiment, the control frame comprises a trigger frame comprising a user information list field indicating the STA.

[333] In one embodiment, the first AP transmits to the second AP a first indication of support, by the first AP, of an assisted media synchronization recovery capability between APs. In another embodiment, the first AP receives from the second AP, a second indication of support by the second AP of the assisted media synchronization recovery capability between APs.

[334] In one modality, the first AP and the second AP form a multi-AP group.

[335] In one embodiment, the first AP, the second AP or the STA comprises a multi-link device (MLD).

[336] Figure 31 illustrates an example 3100 process according to an embodiment. The example 3100 process is provided for illustrative purposes only and is not limiting of embodiments. The 3100 process can be executed by an STA.

[337] As shown in Figure 31, process 3100 begins at step 3102, which includes transmitting, via the STA to a first AP, a first frame, which comprises an AP Assistance Request (AAR) for the first AP. The STA may be associated with a first AP. Petition 870250094447, dated 10 / 16 / 2025, pp. 281 / 332 82 / 89

[338] In one embodiment, the transmission of the first frame comprises the transmission of the first frame through a first link. In one embodiment, the AAR requests that the first AP transmit a third frame, through a second link, to the STA. In one embodiment, the first link and the second link form an NSTR link pair on the STA. In one example, the first link may comprise one of a 2.4 GHz band, a 5 GHz band, a 6 GHz band, or a future band to be defined. Similarly, the second link may comprise one of the 2.4 GHz band, the 5 GHz band, the 6 GHz band, or a future band to be defined, with the second link being different from the first link.

[339] In step 3104, process 3100 involves receiving, via the STA of a second AP, a second frame in response to the first frame. The second STA may not be associated with the second AP.

[340] In one embodiment, receiving the second frame involves transmitting the second frame over a second link. In one embodiment, the second frame assists the STA in regaining media synchronization on the second link. In one embodiment, the second frame comprises an indication from the STA. In one embodiment, the second frame informs the STA to transmit a fourth frame, over the second link, to the first AP.

[341] In one embodiment, the second frame comprises a management frame. In one embodiment, the management frame comprises an action frame which comprises a field of action indicating the STA.

[342] In one embodiment, the second frame comprises a control frame. In one embodiment, the control frame comprises a trigger frame comprising a user information list field indicating the STA.

[343] In one embodiment, the first AP transmits to the second AP an initial indication of support, by the first AP, of an assisted media synchronization recovery capability between APs. In another Petition 870250094447, dated 10 / 16 / 2025, pages 282 / 332 In mode 83 / 89, the first AP receives a second indication of support from the second AP, based on the second AP's ability to recover assisted synchronization between APs.

[344] In one modality, the first AP and the second AP form a multi-AP group.

[345] In one embodiment, the first AP, the second AP or the STA comprises a multi-link device (MLD).

[346] As would be understood by one skilled in the art based on the teachings in the present invention, the embodiments of the present disclosure are not limited to a first AP informing a second AP about an AAR for the second AP transmitted by a STA associated with the second AP. In fact, as described in Figure 32 below, the embodiments can be readily extended to the first AP informing the second AP about a frame of any type from the STA and / or about any information contained in the frame based on an indication that the second AP may not have correctly received the frame.

[347] Figure 32 illustrates an example 3200 process according to an embodiment. The example 3200 process is provided for illustrative purposes only and is not limiting of embodiments. The 3200 process can be performed by a first AP.

[348] As shown in Figure 32, process 3200 begins at step 3202, which involves receiving, by a first AP, a first frame transmitted by a STA to a second AP. The STA may be associated with the second AP, but not the first AP.

[349] In one embodiment, receiving the first frame involves receiving the first frame through a first link.

[350] In step 3204, process 3200 includes, based on the first AP not receiving a second frame from the second AP for the STA in response to the first frame, transmitting, through the first AP to the second AP, a third frame, informing the second AP about the first frame. Petition 870250094447, dated 10 / 16 / 2025, pp. 283 / 332 84 / 89

[351] In one embodiment, the transmission of the second frame comprises transmitting the third frame through the first link or a second link. In one embodiment, the first link and the second link form an NSTR link pair in the STA. In one example, the first link may comprise one of a 2.4 GHz band, a 5 GHz band, a 6 GHz band, or a future band to be defined. Similarly, the second link may comprise one of the 2.4 GHz band, the 5 GHz band, the 6 GHz band, or a future band to be defined, with the second link being different from the first link.

[352] In one embodiment, the third frame comprises an indication of the second link. In one embodiment, the third frame comprises an indication of the STA. In one embodiment, the second AP transmits a fourth frame, through the second link, to the STA in response to the third frame.

[353] In one embodiment, the third frame comprises a management frame. In one embodiment, the management frame comprises an action frame comprising an action field indicating the second link and the STA.

[354] In one embodiment, the third frame comprises a control frame. In one embodiment, the control frame comprises a trigger frame comprising a user information list field indicating the second link and the STA.

[355] In one embodiment, the third frame comprises a data frame. In one embodiment, the data frame comprises a QoS null frame comprising a high-throughput (HT) control field indicating the second link and the STA.

[356] In one modality, the first AP and the second AP form a multi-AP group.

[357] In one embodiment, the first AP, the second AP or the STA comprises a multi-link device (MLD). Petition 870250094447, dated 10 / 16 / 2025, pp. 284 / 332 85 / 89

[358] In one embodiment, the first frame comprises a request frame comprising an association request frame, a re-association request frame, a target wake time (TWT) configuration request frame, a probe request frame, a request to send (RTS) frame, a block acknowledgment (BA) request frame, a data frame, etc.

[359] In one embodiment, the second frame comprises a response frame comprising an association response frame, a re-association response frame, a TWT configuration response frame, a probe response frame, a cleared to send frame (CTS frame), a BA frame, etc.

[360] Thus, there is a method comprising receiving, by a first access point (AP), a first frame, transmitted by a station (STA) to a second AP, comprising a request for the second AP; and

[361] based on the first AP not receiving an acknowledgment frame from the second AP to the STA in response to the first frame, transmitting, by the first AP to the second AP, a second frame.

[362] In the method, the request may be a request for assistance from AP (AAR).

[363] In the method, the request can be for the second link.

[364] In the method, the second frame can be arranged to inform the second AP about the request contained in the first frame.

[365] In the method, receiving the first frame can be understood as receiving the first frame through a first link.

[366] In the method, the transmission of the second frame may comprise the transmission of the second frame through the first link or a second link.

[367] In this method, the AAR can request that the second AP transmit a third frame, via the second link, to the STA. Petition 870250094447, dated 10 / 16 / 2025, pp. 285 / 332 86 / 89

[368] In the method, the second frame can help the STA to recover media synchronization on the second link.

[369] In the method, the second frame may comprise an indication of the second link.

[370] In the method, the second table may comprise an indication of STA.

[371] In this method, the second AP can transmit a third frame, through the second link, to the STA in response to the second frame.

[372] In the method, the second frame may comprise a management frame.

[373] In the method, the second frame may comprise a control frame.

[374] In the method, the second frame may comprise a frame of data.

[375] There is a method which comprises receiving, by a first access point (AP) from a second AP, a first frame informing the first AP about a request for the first AP transmitted by a station (STA) and, based on the receipt of the first frame, transmitting, by the first AP to the STA, a second frame.

[376] In the method, the first frame can inform the first AP about the AAR that operates on the second link.

[377] In this method, the first AP can transmit a second frame, through the second link, to the STA in response to the first frame.

[378] There is a method which comprises transmitting, by a station (STA) to a first AP, a first frame which comprises a request for the first AP; and receiving, by the STA of a second AP, a second frame in response to the first frame.

[379] In the method, the transmission of the first frame may include the transmission of the first frame through a first link. Petition 870250094447, dated 10 / 16 / 2025, pp. 286 / 332 87 / 89

[380] In the method, receiving the second frame can be understood as receiving the second frame through a second link.

[381] In this method, the second frame can tell the STA to transmit a fourth frame, through the second link, to the first AP.

[382] There is a method which involves receiving, by a first access point (AP), a first frame, transmitted by a station (STA) to a second AP, based on the first AP not receiving a second frame from the second AP to the STA in response to the first frame, transmitting, by the first AP to the second AP, a second frame informing the second AP about the first frame.

[383] In the method, the first frame may comprise at least one of a request frame comprising an association request frame, a reassociation request frame, a TWT request frame, a probe request frame, an RTS frame, a block recognition request frame or a data frame.

[384] In the method, the second frame may comprise a response frame comprising at least one of an association response frame, a reassociation response frame, a TWT response frame, a probe response frame, a CTS frame or a BA frame.

[385] In the method, the first AP and the second AP can form a multi-AP group.

[386] In this method, the first AP, the second AP, or the STA may comprise a multi-link device (MLD).

[387] In this method, the first link and the second link can form a pair of non-simultaneous transmit and receive (NSTR) links in the STA.

[388] In the method, the management framework may comprise an action framework comprising an action field indicating the second link and the STA. Petition 870250094447, dated 10 / 16 / 2025, pp. 287 / 332 88 / 89

[389] In the method, the control frame may comprise a trigger frame comprising a user information list field indicating the second link and the STA.

[390] In the method, the data frame may comprise a null frame of QoS comprising a high-throughput (HT) control field indicating the second link and the STA.

[391] In this method, there may be transmission, from the first AP to the second AP, from a first indication of support by the first AP of an assisted media synchronization recovery capability between APs; and receive, by the first AP from the second AP, a second indication of support by the second AP of the assisted media synchronization recovery capability between APs.

[392] There is a device arranged, when acting as a first AP, to perform operations comprising receiving a first frame, transmitted by a station (STA) to a second AP, comprising a request to the second AP; and, based on the first AP not receiving an acknowledgment frame from the second AP to the STA in response to the first frame, transmitting, to the second AP, a second frame informing the second AP of the request comprised in the first frame.

[393] There is a device available, when acting as a first STA, to perform operations that include

[394] receive, by a first access point (AP) from a second AP, a first frame informing the first AP about a request for the first AP transmitted by a station (STA); and, based on the receipt of the first frame, transmit, to the STA, a second frame.

[395] There is a device, when acting as a STA, arranged to perform operations comprising transmitting, by a station (STA) to a first AP, a first frame comprising a request to the first AP; and receiving, by the STA of a second AP, a second frame in response to the first frame. Petition 870250094447, dated 10 / 16 / 2025, pp. 288 / 332 89 / 89

[396] There is a wireless communication network comprising at least two APs and at least one STA according to the description mentioned above.

[397] A computer program product is provided, stored on a computer-readable medium, arranged, when executed on a processor, to cause the processor to execute the method described above. Petition 870250094447, dated 10 / 16 / 2025, pp. 289 / 332

Claims

1 / 7 CLAIMS 1. A method characterized by comprising: receiving, by a first access point (AP), a first frame, transmitted by a station (STA) to a second AP, which comprises a request for the second AP; and based on the first AP not receiving an acknowledgment frame from the second AP to the STA in response to the first frame, transmitting, by the first AP to the second AP, a second frame.

2. Method according to claim 1, characterized in that the request is a request for AP assistance (AAR).

3. Method, according to claim 1 or 2, characterized in that the request is for the second link.

4. A method, according to any one of claims 1 to 3, characterized in that the second frame is arranged to inform the second AP about the request comprised in the first frame.

5. A method, according to any of the preceding claims, characterized in that receiving the first frame comprises receiving the first frame through a first link.

6. A method, according to any of the preceding claims, characterized in that the transmission of the second frame comprises transmitting the second frame through the first link or a second link.

7. A method, according to any of the preceding claims, characterized in that the AAR requests that the second AP transmit a third frame, through the second link, to the STA.

8. A method, according to any of the preceding claims, characterized in that the second frame assists the STA in regaining media synchronization on the second link.

9. Method, according to any of the preceding claims, characterized in that the second frame comprises an indication of the second link. Petition 870250094447, dated 10 / 16 / 2025, pp. 290 / 332 2 / 7 10. Method, according to any of the preceding claims, characterized in that the second frame comprises an indication of the STA.

11. A method, according to any of the preceding claims, characterized in that the second AP transmits a third frame, through the second link, to the STA in response to the second frame.

12. A method, according to any of the preceding claims, characterized in that the second framework comprises a management framework.

13. A method, according to any of the preceding claims, characterized in that the second frame comprises a control frame.

14. A method, according to any of the preceding claims, characterized in that the second frame comprises a data frame.

15. A method characterized by comprising: receiving, by a first access point (AP) from a second AP, a first frame informing the first AP about a request for the first AP transmitted by a station (STA); and based on the receipt of the first frame, transmitting, by the first AP to the STA, a second frame.

16. Method according to claim 15, characterized in that the request is a request for AP assistance (AAR).

17. Method, according to any one of claims 15 to 16, characterized in that receiving the first frame comprises receiving the first frame through a first link or a second link.

18. Method, according to any one of claims 15 to 17, characterized in that the first frame informs the first AP about the AAR operating on the second link.

19. Method, according to any one of claims 16 to 18, characterized in that the AAR requests that the first AP transmit the second frame, through the second link, to the STA. Petition 870250094447, dated 16 / 10 / 2025, p. 291 / 332 3 / 7 20. A method, according to any one of claims 15 to 19, characterized in that the first frame assists the STA in recovering media synchronization on the second link.

21. A method, according to any one of claims 15 to 20, characterized in that the first frame comprises an indication of the second link.

22. Method, according to any one of claims 15 to 21, characterized in that the first frame comprises an indication of the STA.

23. A method, according to any one of claims 15 to 22, characterized in that the first AP transmits a second frame, through the second link, to the STA in response to the first frame.

24. Method, according to any one of claims 15 to 23, characterized in that the first frame comprises a management frame.

25. Method, according to any one of claims 15 to 24, characterized in that the first frame comprises a control frame.

26. Method, according to any one of claims 15 to 25, characterized in that the first frame comprises a data frame.

27. Method characterized by comprising: transmitting, by a station (STA) to a first AP, a first frame comprising a request for the first AP; and receiving, by the STA of a second AP, a second frame in response to the first frame.

28. Method according to claim 27, characterized in that the request is a request for AP assistance (AAR).

29. Method, according to claim 27 or 28, characterized in that the transmission of the first frame comprises transmitting the first frame through a first link.

30. Method, according to any one of claims 27 to 29, characterized in that receiving the second frame comprises receiving the second frame through a second link. Petition 870250094447, dated 10 / 16 / 2025, pp. 292 / 332 4 / 7 31. A method, according to any one of claims 28 to 30, characterized in that the AAR requests that the first AP transmit a third frame, through the second link, to the STA.

32. A method, according to any one of claims 27 to 31, characterized in that the second frame assists the STA in recovering media synchronization on the second link.

33. Method, according to any one of claims 27 to 32, characterized in that the second frame comprises an indication of the STA.

34. A method, according to any one of claims 27 to 33, characterized in that the second frame informs the STA to transmit a fourth frame, through the second link, to the first AP.

35. Method, according to any one of claims 27 to 34, characterized in that the second frame comprises a management frame.

36. Method, according to any one of claims 27 to 35, characterized in that the second frame comprises a control frame.

37. Method characterized by comprising: receiving, by a first access point (AP), a first frame, transmitted by a station (STA) to a second AP; based on the first AP not receiving a second frame from the second AP to the STA in response to the first frame, transmitting, by the first AP to the second AP, a second frame informing the second AP about the first frame.

38. Method, according to claim 37, characterized in that receiving the first frame comprises receiving the first frame through a first link.

39. Method, according to any one of claims 37 to 38, characterized in that the transmission of the second frame comprises transmitting the second frame through the first link or a second link. Petition 870250094447, dated 10 / 16 / 2025, pp. 293 / 332 5 / 7 40. Method, according to any one of claims 37 to 39, characterized in that the second frame comprises an indication of the second link.

41. Method, according to any one of claims 37 to 40, characterized in that the second frame comprises an indication of the STA.

42. A method, according to any one of claims 37 to 41, characterized in that the second AP transmits a third frame, through the second link, to the STA in response to the second frame.

43. Method, according to any one of claims 37 to 42, characterized in that the second frame comprises a management frame.

44. Method, according to any one of claims 37 to 43, characterized in that the second frame comprises a control frame.

45. Method, according to any one of claims 37 to 44, characterized in that the second frame comprises a data frame.

46. ​​A method according to any one of claims 37 to 45, characterized in that the first frame comprises at least one of a request frame comprising an association request frame, a reassociation request frame, a TWT request frame, a probe request frame, an RTS frame, a block recognition request frame, or a data frame.

47. A method according to any one of claims 37 to 46, characterized in that the second frame comprises a response frame comprising at least one of an association response frame, a reassociation response frame, a TWT response frame, a probe response frame, a CTS frame, or a BA frame.

48. Method, according to any of the preceding claims, characterized in that the first AP and the second AP form a multi-AP group. Petition 870250094447, dated 10 / 16 / 2025, pp. 294 / 332 6 / 7 49. A method, according to any of the preceding claims, characterized in that the first AP, the second AP, or the STA comprises a multi-link device (MLD).

50. A method, according to any of the preceding claims, characterized in that the first link and the second link form a pair of non-simultaneous transmit and receive (NSTR) links in the STA.

51. Method, according to any one of claims 12 to 14, 24, 35 and 43, characterized in that the management framework comprises an action framework comprising an action field indicating the second link and the STA.

52. Method, according to any one of claims 12 to 14, 25, 36 and 44, characterized in that the control frame comprises a trigger frame comprising a user information list field indicating the second link and the STA.

53. Method, according to any one of claims 12 to 14, 25 and 46, characterized in that the data frame comprises a QoS null frame comprising a high-throughput (HT) control field indicating the second link and the STA.

54. A method, according to any of the preceding claims, characterized by comprising: transmitting, by the first AP to the second AP, a first indication of support by the first AP of an assisted media synchronization recovery capability between APs; and receiving, by the first AP from the second AP, a second indication of support by the second AP of the assisted media synchronization recovery capability between APs.

55. Device characterized by being arranged, when acting as a first AP, to perform operations comprising: receiving a first frame transmitted by a station (STA) to a second AP, which comprises a request for the second AP; and Petition 870250094447, of 10 / 16 / 2025, p. 295 / 332 7 / 7 based on the first AP not receiving an acknowledgment frame from the second AP for the STA in response to the first frame, transmitting, to the second AP, a second frame informing the second AP about the request comprised in the first frame.

56. A device characterized by being arranged, when acting as a first STA, to perform operations that include: receiving, by a first access point (AP) of a second AP, a first frame informing the first AP about a request for the first AP transmitted by a station (STA); and based on the receipt of the first frame, transmitting a second frame to the STA.

57. Device, when acting as a first STA, characterized by being arranged to: perform operations comprising; transmitting, by a station (STA) to a first AP, a first frame comprising a request for the first AP; and receiving, by the STA of a second AP, a second frame in response to the first frame.

58. Wireless communication network characterized by comprising at least two APs and at least one STA as defined in any of the preceding claims.

59. Computer program product stored on a computer-readable medium characterized in that, when executed on a processor, it is arranged to cause the processor to execute the method as defined in any one of claims 1 to 54. Petition 870250094447, dated 10 / 16 / 2025, pp. 296 / 332

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