Trigger frame duration coordination for multiple access point transmissions

Abstract

In an aspect, a first access point (AP) receives a first frame from a second AP, the first frame indicating a number of stations (STAs) making uplink (UL) transmissions to the second AP. Transmitting, by the first AP, a second frame to the second AP, the second frame indicating: an allocated time of a transmission opportunity (TXOP) obtained by the first AP; an identifier of the second AP; and a time period for a downlink physical layer protocol data unit (DL PPDU) within the allocation time, the downlink physical layer protocol data unit including a trigger frame for the STA, where the time period is based on the number of STAs. In another aspect, a first AP transmits a first frame indicating a number of STAs to a second AP. The first AP receives a second frame from the second AP, the second frame indicating a time period for a DL PPDU, the DL PPDU including a trigger frame for the STA.

Description

Cross-references to related applications

[0001] This application claims priority to U.S. Provisional Application No. 63 / 543,121, filed on October 9, 2023, which is hereby incorporated in its entirety by reference. Attached Figure Description

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

[0003] Figure 1 An example wireless communication network in which embodiments of the present disclosure may be implemented is shown.

[0004] Figure 2 A block diagram illustrating an example implementation of a station (STA) and access point (AP).

[0005] Figure 3 An example of the Media Access Control (MAC) frame format is shown.

[0006] Figure 4 This shows an example of a Quality of Service (QoS) empty frame that indicates buffer status information.

[0007] Figure 5 This shows an instance format of a Physical Layer (PHY) Protocol Data Unit (PPDU).

[0008] Figure 6 The example frame shown is an instance multi-user request to send (MU-RTS) trigger frame that can be used to trigger a transmission opportunity (TXOP) sharing (TXS) procedure.

[0009] Figure 7 This shows an example of the TXS program (mode=1).

[0010] Figure 8 This shows an example of the TXS program (mode=2). Figure 9 This shows an example of a multi-AP network.

[0011] Figure 10 This illustrates Coordinated Orthogonal Frequency Division Multiple Access (C-OFDMA).

[0012] Figure 11 This is to illustrate an example of the TXS procedure between APs.

[0013] Figure 12 Examples of Physical Layer Protocol Data Units (PPDUs) that can be used for downlink (DL) PPDUs or uplink (UL) PPDUs are shown.

[0014] Figure 13 To show Figure 11 The example shown is an instance of a potential problem in the AP-to-TXS procedure.

[0015] Figure 14 An example of an AP-to-AP TXS procedure is shown according to an embodiment.

[0016] Figure 15 An example of an AP-to-AP TXS procedure according to another embodiment is shown.

[0017] Figure 16 The instance aggregation control (A-Control) field, which can be used in the embodiments, is shown.

[0018] Figure 17 The instance information elements that can be used in the embodiments are shown.

[0019] Figure 18 An example process according to an embodiment is shown.

[0020] Figure 19 Another example process according to an embodiment is shown.

[0021] Figure 20 Another example process according to an embodiment is shown.

[0022] Figure 21 Another example process according to an embodiment is shown. Detailed Implementation

[0023] In this disclosure, various 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 apparent to those skilled in the art that various changes in form and detail can be made therein without departing from the scope of the invention. Alternative embodiments will become apparent to those skilled in the art upon reading this specification. The embodiments of the invention are not to be limited to any of the described exemplary embodiments. Embodiments of this disclosure will be described with reference to the accompanying drawings. Limitations, features, and / or elements from the disclosed exemplary embodiments can be combined to create further embodiments within the scope of this disclosure. Any diagrams highlighting functionality and advantages are given for illustrative purposes only. The disclosed architecture is flexible and configurable enough that it can be utilized in ways other than those shown. For example, the actions listed in any flowchart can be reordered or used only optionally in certain embodiments.

[0024] The embodiments can be configured to operate as needed. When certain criteria are met, the disclosed mechanisms can be executed, for example, in stations, access points, radio environments, networks, or combinations thereof. Instance standards can be based at least in part on, for example, wireless device or network node configuration, traffic load, initial system settings, packet size, traffic characteristics, or combinations thereof. Various instance embodiments can be applied when one or more criteria are met. Therefore, it is possible to implement instance embodiments that selectively implement the disclosed protocols.

[0025] In this disclosure, “a” and “an”, and similar phrases, will be interpreted as “at least one” and “one or more”. Similarly, any term ending with the suffix “(s)” will be interpreted as “at least one” and “one or more”. In this disclosure, the term “may” is interpreted as “may, for example.” In other words, the term “may” indicates that the phrase following the term “may” is an example of one of a variety of suitable possibilities that may or may not be used in one or more of the various embodiments. As used herein, the terms “comprising” and “consisting of” enumerate one or more components of the element being described. The terms “comprising” and “including” are interchangeable and do not exclude the inclusion of unlisted components in the element being described. In contrast, “consisting of” provides a complete enumeration of the one or more components of the element being described. As used herein, the term “based on” can be interpreted as “at least partially based on” rather than, for example, “based on only.” As used herein, the term “and / or” indicates any possible combination of the enumerated elements. For example, "A, B and / or C" can mean A; B; C; A and B; A and C; B and C; or A, B and C.

[0026] If A and B are sets, and every element of A is an element of B, then A is called a subset of B. In this specification, only non-empty sets and subsets are considered. For example, possible subsets of B = {STA1, STA2} are: {STA1}, {STA2}, and {STA1, STA2}. The phrase “based on” (or equivalently “at least based on”) indicates that the phrase following the term “based on” is an instance of one of a variety of suitable possibilities that may or may not be used in one or more of the various embodiments. The phrase “in response to” (or equivalently “at least in response to”) indicates that the phrase following the phrase “in response to” is an instance of one of a variety of suitable possibilities that may or may not be used in one or more of the various embodiments. The phrase “depends on” (or equivalently “at least depends on”) indicates that the phrase following the phrase “depends on” is an instance of one of a variety of suitable possibilities that may or may not be used in one or more of the various embodiments. The phrase “adopt / use” (or equivalently “at least adopt / use”) indicates that the phrase following the phrase “adopt / use” is an instance of one of a variety of suitable possibilities that may or may not be used in one or more of the various embodiments.

[0027] The term "configurable" can refer to the capabilities of a device, whether the device is in an operational or non-operational state. "Configurable" can refer to specific settings within the device that affect its operational characteristics, regardless of whether the device is in an operational or non-operational state. In other words, hardware, software, firmware, registers, memory values, etc., can be "configured" within the device to provide specific characteristics to the device, whether the device is in an operational or non-operational state. For example, the term "control message generated in the device" can mean that the control message has parameters that can be used to configure specific characteristics or to perform certain actions within the device, regardless of whether the device is in an operational or non-operational state.

[0028] In this disclosure, a parameter (or equivalently referred to as a field or information element: IE) may include one or more information objects, and an information object may include one or more other objects. For example, if parameter (IE)N includes parameter (IE)M, and parameter (IE)M includes parameter (IE)K, and parameter (IE)K includes parameter (information element)J, then, for example, N includes K, and N includes J. In exemplary embodiments, when one or more messages / frames include multiple parameters, this means that one of the multiple parameters is in at least one of the one or more messages / frames, but not necessarily in every one of the one or more messages / frames.

[0029] Many of the proposed features are described as optional using the word "may" or parentheses. For brevity and readability, this disclosure does not explicitly describe every permutation that can be obtained by selecting from the group of optional features. This disclosure should be interpreted as explicitly disclosing all such permutations. For example, a system described as having three optional features can be embodied in seven ways: having only one of the three possible features, having any two of the three possible features, or having three of the three possible features.

[0030] Many of the elements described in the disclosed embodiments can be implemented as modules. A module is defined herein as an element that performs the defined function and has the defined interface to other elements. Modules described in this disclosure can be implemented in hardware, software combined with hardware, firmware, wet hardware (e.g., hardware with biological elements), or combinations thereof, all of which may be behaviorally equivalent. For example, a module can be implemented as a software routine written in a computer language configured to be executed by a hardware machine (such as C, C++, Fortran, Java, Basic, Matlab, etc.) or a modeling / simulation program (such as Simulink, Stateflow, GNU Octave, or LabVIEW MathScript). It is possible to implement modules using physical hardware incorporating discrete or programmable analog, digital, and / or quantum hardware. Examples of programmable hardware include: computers, microcontrollers, microprocessors, application-specific integrated circuits (ASICs); field-programmable gate arrays (FPGAs); and complex programmable logic devices (CPLDs). Computers, microcontrollers, and microprocessors are programmed using languages ​​such as assembly, C, C++, etc. FPGAs, ASICs, and CPLDs are typically programmed using hardware description languages ​​(HDLs), such as VHSIC Hardware Description Language (VHDL) or Verilog, which configure connections between internal hardware modules with limited functionality on the programmable device. The aforementioned techniques are often used in combination to achieve the desired functional modules.

[0031] Figure 1 An example wireless communication network in which embodiments of the present disclosure may be implemented is shown.

[0032] like Figure 1 As shown, the example wireless communication network may include an IEEE 802.11 (WLAN) infrastructure network 102. The WLAN infrastructure network 102 may include one or more Basic Service Sets (BSS) 110 and 120 and a Distribution System (DS) 130.

[0033] BSS 110-1 and 110-2 each contain a set of access points (APs or AP STAs) and at least one station (STA or non-AP STA). For example, BSS 110-1 contains AP 104-1 and STA 106-1, and BSS 110-2 contains AP 104-2 and STAs 106-2 and 106-3. The APs and at least one STA in the BSS perform association procedures to communicate with each other.

[0034] The DS 130 can be configured to connect BSS 110-1 and BSS 110-2. Therefore, the DS 130 can enable Extended Service Set (ESS) 150. Within the ESS 150, APs 104-1 and 104-2 are connected via the DS 130 and can have the same Service Set Identifier (SSID).

[0035] The WLAN infrastructure network 102 can be coupled to one or more external networks. For example, such as Figure 1 As shown, WLAN infrastructure network 102 can be connected to another network 108 (e.g., 802.X) via portal 140. Portal 140 can act as a bridge connecting DS 130 of WLAN infrastructure network 102 to the other network 108.

[0036] Figure 1 The example wireless communication network shown may further comprise one or more self-organizing networks or independent BSSs (IBSSs). A self-organizing network or IBSS is a network of multiple STAs contained within each other's communication range. The multiple STAs are configured such that they can communicate with each other using direct peer-to-peer communication (i.e., without via an AP).

[0037] For example, in Figure 1 In this configuration, STAs 106-4, 106-5, and 106-6 can be configured to form a first IBSS 112-1. Similarly, STAs 106-7 and 106-8 can be configured to form a second IBSS 112-2. Since an IBSS does not contain an AP, it does not contain a centralized management entity. Instead, the STAs within an IBSS are managed in a distributed manner. The STAs forming an IBSS can be fixed or mobile.

[0038] A STA, serving as the intended functional medium, may include a Media Access Control (MAC) layer conforming to the IEEE 802.11 standard. The physical layer interface of the radio medium can be used in both AP and non-AP stations (STAs). STAs may also be referred to using various other terms, including mobile terminal, radio device, radio transmit / receive unit (WTRU), user equipment (UE), mobile station (MS), mobile subscriber unit, or user. For example, the term "user" can be used to refer to a STA participating in uplink multi-user multiple-input multiple-output (MU MIMO) and / or uplink orthogonal frequency division multiple access (OFDMA) transmissions.

[0039] Physical Layer (PHY) Protocol Data Units (PPDUs) can be composite structures containing a PHY preamble and a payload in the form of PHY Service Data Units (PSDUs). For example, a PSDU may contain a PHY preamble and a header and / or one or more MAC Protocol Data Units (MPDUs). The information provided in the PHY preamble can be used by the receiving device to decode subsequent data in the PSDU. When the PPDU is transmitted over a bonded channel (a channel formed by channel bonding), the preamble field can be copied and transmitted in each of the multiple component channels. The PHY preamble can contain both a traditional portion (or "traditional preamble") and a non-traditional portion (or "non-traditional preamble"). The traditional preamble can be used for purposes such as packet detection, automatic gain control, and channel estimation. The traditional preamble is also typically used to maintain compatibility with legacy devices. The format, encoding, and information provided in the non-traditional portion of the preamble are based on the specific IEEE 802.11 protocol to be used for transmitting the payload.

[0040] A frequency band can contain one or more sub-bands or frequency channels. For example, PPDUs conforming to IEEE 802.11n, 802.11ac, 802.11ax, and / or 802.11be standard modifications can be transmitted in 2.4 GHz, 5 GHz, and / or 6 GHz bands, each band can be divided into multiple 20 MHz channels. PPDUs can be transmitted through physical channels with a minimum bandwidth of 20 MHz. Larger channels can be formed through channel bonding. For example, PPDUs can be transmitted through physical channels with bandwidths of 40 MHz, 80 MHz, 160 MHz, or 320 MHz by bonding multiple 20 MHz channels together.

[0041] Figure 2 A block diagram illustrating an example implementation of STA 210 and AP 260 is provided. Figure 2As shown, STA 210 may include at least one processor 220, memory 230, and at least one transceiver 240. AP 260 may include at least one processor 270, memory 280, and at least one transceiver 290. Processors 220 / 270 may be operatively connected to memory 230 / 280 and / or transceiver 240 / 290.

[0042] Processors 220 / 270 can implement the functions of the PHY layer, MAC layer, and / or logical link control (LLC) layer of the corresponding device (STA 210 or AP 260). Processors 220 / 270 may include one or more processors and / or one or more controllers. For example, one or more processors and / or one or more controllers may include, for example, a general-purpose processor, a digital signal processor (DSP), a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), logic circuitry, or a chipset.

[0043] Memory 230 / 280 may include read-only memory (ROM), random access memory (RAM), flash memory, memory card, storage medium, and / or other storage units. Memory 230 / 280 may include one or more non-transitory computer-readable media. Memory 230 / 280 may store computer program instructions or code that can be executed by processor 220 / 270 to perform one or more of the operations / embodiments discussed in this application. Memory 230 / 280 may be implemented (or located) within processor 220 / 270 or external to processor 220 / 270. Memory 230 / 280 may be operatively connected to processor 220 / 270 in various ways known in the art.

[0044] Transceiver 240 / 290 can be configured to transmit / receive radio signals. In embodiments, transceiver 240 / 290 can implement the PHY layer of the corresponding device (STA 210 or AP 260). In embodiments, STA 210 and / or AP 260 can be multi-link devices (MLDs), which are devices capable of operating on multiple links defined by the IEEE 802.11 standard. Therefore, STA 210 and / or AP 260 can each implement multiple PHY layers. Multiple PHY layers can be implemented using one or more of transceivers 240 / 290.

[0045] Target Wake-up Time (TWT) (a feature introduced in the IEEE 802.11ah standard) allows STAs to manage activity in the BSS by scheduling STAs to operate at different times to reduce contention. TWT can allow STAs to reduce the amount of time required for a STA utilizing power management modes to wake up. TWT can be a standalone TWT or a broadcast TWT. Standalone TWTs follow a negotiated TWT protocol between STAs. Broadcast TWTs are based on schedule settings and are provided to STAs by the AP.

[0046] In a typical TWT, the STA that requests the TWT protocol is called the TWT requesting STA. For example, the TWT requesting STA can be a non-AP STA. The STA that responds to the request is called the TWT responding STA. For example, the TWT responding STA can be an AP. The TWT requesting STA is allocated a specific time to wake up the frame and exchange the frame with the TWT responding STA. The TWT requesting STA can transmit wake-up scheduling information to the TWT responding STA. When the TWT protocol is established between the TWT responding STA and the TWT requesting STA, the TWT responding STA can transmit the TWT value to the TWT requesting STA.

[0047] When using explicit TWT, the TWT requesting STA can be woken up and perform frame exchange. The TWT requesting STA can receive the next TWT information in the response from the TWT responding STA. When using implicit TWT, the TWT requesting STA can calculate the next TWT by adding a fixed value to the current TWT value.

[0048] The TWT value of an implicit TWT can be periodic. A TWT request STA operating according to the implicit TWT protocol can determine the start time of the next TWT service cycle (TWT SP) by adding the value of the TWT wake-up interval associated with the TWT protocol to the start time of the current TWT SP. A TWT response STA can contain a series of start times of TWT SPs corresponding to a single TWT stream identifier of the implicit TWT protocol in the target wake-up time field of the TWT element. The TWT element can include a 'Accept TWT' value in the TWT setting command field. The start time of the TWT SP series can indicate the start time of the first TWT SP in the series. The start time of subsequent TWT SPs can be determined by adding the value of the TWT wake-up interval to the start time of the current TWT SP. In an instance, a TWT request STA that wakes up for an implicit TWT SP can enter a dozing state after a TWT SP has passed or after receiving a service cycle end (EOSP) field equal to 1 from a TWT response STA (whichever occurs first).

[0049] A TWT session can be negotiated between the AP and STA. The TWT session can configure TWT SPs for DL ​​and UL traffic between the AP and STA. Expected traffic may be limited by the negotiated SP. A TWT SP can start at a specific time. A TWT SP can run for a continuous SP duration. A TWT SP can repeat for each SP time interval.

[0050] Figure 3 Example 300 of the MAC frame format is shown. In operation, the STA can construct a subset of MAC frames for transmission and can decode the received subset of MAC frames during verification. The specific subset of frames that the STA can construct and / or decode can be determined by the functions supported by the STA. The STA can use the Frame Check Sequence (FCS) contained in the frame to verify the received MAC frame and can interpret certain fields based on the MAC header of all frames.

[0051] like Figure 3 As shown, a MAC frame includes a MAC header, a variable-length frame body, and a frame check sequence (FCS).

[0052] The MAC header contains a frame control field, an optional duration / ID field, an address field, an optional sequence control field, an optional QoS control field, and an optional HT control field.

[0053] The frame control field includes the following subfields: protocol version, type, subtype, to DS, from DS, more fragments, retry, power management, more data, protected frames, and +HTC.

[0054] The size and placement of the protocol version subfield remain unchanged across all revisions of the IEEE 802.11 standard. For MAC frames, the value of the protocol version subfield is 0.

[0055] The type and subtype subfield together identify the function of a MAC frame. There are three frame types: control, data, and management. Each of the frame types has several defined subtypes. Bits within the subtype subfield are used to indicate specific modifications to the base data frame (subtype 0). For example, in a data frame, 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, i.e., a data frame that includes the QoS control field in its MAC header. When set to 1 in the data subtype, the second MSB of the subtype field (bit 6 (B6) of the frame control field) indicates a data frame that does not include a frame body field.

[0056] The To DS subfield indicates whether the data frame is directed to the Distribution System (DS). The From DS subfield indicates whether the data frame originated from the DS.

[0057] In all data or management frames that have another fragment following the MAC Service Data Unit (MSDU) or MAC Management Protocol Data Unit (MMPDU) carried by the MAC frame, the More Fragments subfield is set to 1. In all other frames in which the More Fragments subfield exists, it is set to 0.

[0058] In any data or management frame that is a retransmission of an earlier frame, the retry subfield is set to 1. In all other frames in which the retry subfield exists, it is set to 0. The receiving STA uses this indication to assist in its process of eliminating duplicate frames. These rules do not apply to frames sent by the STA according to the block protocol.

[0059] The power management subfield is used to indicate the power management mode of the STA.

[0060] The More Data subfield in Power Saving (PS) mode indicates to the STA that a bufferable unit (BU) is buffered at the AP for the STA. The More Data subfield is valid in separately addressed data or management frames transmitted from the AP to the STA in PS mode. The More Data subfield is set to 1 to indicate that at least one additional buffered BU exists for the STA.

[0061] If the frame body field contains information that has been processed by an cryptographic encapsulation algorithm, the protected frame subfield is set to 1.

[0062] The +HTC subfield indicates that the MAC frame contains the HT control field.

[0063] The Duration / ID field in the MAC header indicates various contents depending on the frame type and subtype, as well as the QoS capabilities of the sending STA. For example, in a control frame of the Power Saving Polling (PS-Poll) subtype, the Duration / ID field carries the Association Identifier (AID) of the STA that has transmitted a frame in 14 least significant bits (LSBs), and both most significant bits (MSBs) are set to 1. In other frames transmitted by the STA, the Duration / ID field contains a duration value (in microseconds) for the receiver to use to update the Network Allocation Vector (NAV). The NAV is a counter that indicates to the STA the amount of time it must postpone access to the shared medium during this period.

[0064] A MAC frame format may contain up to four address fields. These fields are used to indicate the Basic Service Set Identifier (BSSID), source address (SA), destination address (DA), transport address (TA), and receive address (RA). Some frames may not contain certain address fields. Some address fields can be specified by the relative order of address fields (1-4) within the MAC header, regardless of the address type present in those fields. Specifically, address 1 always identifies one or more intended receivers of the frame, and address 2 (if present) always identifies the transmitter of the frame.

[0065] The sequence control field contains two subfields: a sequence number subfield and a fragment number subfield. In a data frame, the sequence number subfield indicates the sequence number of the MSDU (if not in an aggregated MSDU (A-MSDU)) or A-MSDU. In a management frame, the sequence number subfield indicates the sequence number of the frame. The fragment number subfield indicates the number of each fragment of the MSDU or MMPDU. In the first or only fragment of an MSDU or MMPDU, the fragment number is set to 0 and increments by one for each subsequent fragment of that MSDU or MMPDU. In a MAC Protocol Data Unit (MPDU) containing an A-MSDU or in an MPDU containing an unfragmented MSDU or MMPDU, the fragment number is set to 0. The fragment number remains constant throughout all retransmissions of the fragment.

[0066] The QoS control field identifies the Traffic Class (TC) or Traffic Stream (TS) to which the MAC 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 the type of transport STA. The QoS control field exists in all data frames where the QoS subfield of the subtype subfield is equal to 1.

[0067] The HT control field exists in QoS data frames, QoS empty frames, and management frames, which are determined by the +HTC subfield of the frame control field.

[0068] The frame body field is a variable-length field that contains information specific to individual frame types and subtypes. It can contain one or more MSDUs or MMPDUs. The minimum length of the frame body is 0 octets.

[0069] The FCS field contains a 32-bit Cyclic Redundancy Check (CRC) code. The FCS field value is calculated on all fields of the MAC header and the frame body field.

[0070] Figure 4Example 400 shows a Quality of Service (QoS) empty frame indicating buffer status information. A QoS empty frame is a QoS data frame with an empty frame body. A QoS empty frame contains a QoS control field and an optional HT control field, which may include a Buffer Status Report (BSR) control subfield. QoS empty frames indicating buffer status information can be transmitted from a STA to an AP.

[0071] The QoS control field may include a Traffic Identifier (TID) subfield, an ACK policy indicator subfield, and a queue size subfield (or a Requested Transmission Opportunity (TXOP) duration subfield).

[0072] The TID subfield identifies the TC or TS of the traffic requesting a TXOP by setting the requested TXOP duration or queue size subfield. The encoding of the TID subfield depends on the access policy (e.g., the Enhanced Distributed Channel Access (EDCA) access policy allows values ​​from 0 to 7 to identify the user priority of the TC or TS).

[0073] The ack policy indicator subfield, along with other information, identifies the acknowledgment policy to be followed after the delivery of the MPDU (e.g., normal ack, implicit block ack request, no ack, block ack, etc.).

[0074] The queue size subfield is an 8-bit field that indicates the amount of buffered traffic at the STA used to transmit a given TC or TS to the AP identified by the receiver address of the frame containing this subfield. The queue size subfield is present in QoS empty frames transmitted by the STA when bit 4 of the QoS control field is set to 1. The AP can use the information contained in the queue size subfield to determine the t TXOP duration allocated to the STA or to determine the uplink (UL) resources allocated to the STA.

[0075] In frames transmitted by or to non-HE STAs, the following rules apply to queue size values: - The queue size value is the approximate total size of all MSDUs and A-MSDUs (excluding MSDUs or A-MSDUs contained in this QoS data frame) buffered at the STA in the delivery queue for MSDUs and A-MSDUs, rounded up to the nearest multiple of 256 octets and expressed in units of 256 octets, where the TID value is equal to the value indicated in the TID subfield of the QoS control field.

[0076] - A queue size value of 0 is only used to indicate that there is no buffered traffic in the queue used for the specified TID.

[0077] - For all sizes greater than 64,768 octets, use a queue size value of 254.

[0078] - The queue size value of 255 is used to indicate an unspecified or unknown size.

[0079] In frames sent from HE STA to HE AP, the following rules may be applied to queue size values.

[0080] Queue size value QS It is the approximate total size of all MSDUs and A-MSDUs buffered at the STA in the delivery queue for MSDUs and A-MSDUs (including MSDUs or A-MSDUs contained in the same PSDU as the frame containing the queue size subfield), represented in octets, where the TID value is equal to the value indicated in the TID subfield of the QoS control field.

[0081] The queue size subfield contains the scaling factor subfield in bits B14 to B15 of the QoS control field and the unscaled value in bits B8 to B13 of the QoS control field. UV The scaling factor subfield provides the scaling factor. on .

[0082] STA from includes scaling factor SF and Unscaled value UV The received QoS control field is used to obtain the queue size. QS ,as follows: QS = 16 × UV ,if SF Equal to 0; 1024 + 256 × UV ,if SF It equals 1; 17,408 + 2048 × UV ,if SF It equals 2; 148 480 + 32 768 × UV ,if SF Equal to 3 and UV Less than 62; >2 147 328, if SF Equal to 3 and UV Equals 62; not specified or unknown ,if SF Equal to 3 and UV It equals 63.

[0083] The Requested TXOP Duration subfield, which can be included in place of the Queue Size subfield, indicates the duration, in 32 microseconds (μs), required for the sending STA to determine the next TXOP for its 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 the requested TXOP duration in increments of 32 μs within the range of 32 μs to 8160 μs.

[0084] The HT control field may contain a BSR control subfield, which may contain buffer status information for UL MU operations. The BSR control subfield may be formed by the following: the Access Category Index (ACI) bitmap subfield, the ΔTID subfield, the ACI high subfield, the scaling factor subfield, the queue size high subfield, and the queue size full subfield of the HT control field.

[0085] The ACI bitmap subfield indicates the access category for reporting buffer states (e.g., B0: Best Effort (AC_BE); B1: Background (AC_BK); B2: Video (AC_VI); B3: Audio (AC_VO), etc.). Each bit of the ACI bitmap subfield is set to 1 to indicate that the buffer state of the corresponding AC is included in the queue size full subfield, and is otherwise set to 0, except that if the ACI bitmap subfield is 0 and the ΔTID subfield is 3, then the buffer state of all 8 TIDs is included.

[0086] The ΔTID subfield, together with the value of the ACI bitmap subfield, indicates the number of TIDs that the STA is reporting in the buffer state.

[0087] The ACI high subfield indicates the ACI of the AC of the BSR in the queue size high subfield. The ACI to AC mapping is defined as ACI value 0 mapping to AC_BE, ACI value 1 mapping to AC_BK, ACI value 2 mapping to AC_VI, and ACI value 3 mapping to AC_VO.

[0088] The scaling factor subfield indicates the units of the queue size height subfield and the queue size full subfield. SF It is represented by an octet.

[0089] The queue size high subfield indicates the amount of buffered traffic (in words) of the AC identified by the ACI high subfield. SF (in octets), which are intended for use with the STA identified by the receiver address of the frame containing the BSR control subfield.

[0090] The queue size full subfield indicates the amount of buffered traffic (in words) for all Acs identified by the ACI bitmap subfield. SF (in octets), which are intended for use with the STA identified by the receiver address of the frame containing the BSR control subfield.

[0091] The queue size values ​​in the queue size high subfield and queue size full subfield are the total size of all MSDUs and A-MSDUs buffered at the STA in the delivery queues of MSDUs and A-MSDUs associated with one or more ACs specified in the ACI high subfield and ACI bitmap subfield, respectively (including MSDUs or A-MSDUs contained in the same PSDU as the frame containing the BSR control subfield), rounded up. SF The closest multiple of an octet.

[0092] The queue size value of 254 in both the queue size high subfield and the queue size full subfield indicates that the amount of buffered traffic is greater than 254 × SF Eight-bit byte. The queue size value of 255 in both the queue size high and queue size full subfields indicates that the amount of buffered traffic is unspecified or unknown. The queue size value of a QoS data frame containing fragments can remain constant, even if the amount of queued traffic changes as consecutive fragments are transmitted.

[0093] The MAC service provides peer entities with the ability to exchange MSDUs. To support this service, the local MAC uses an underlying PHY-level service to transfer MSDUs to the peer MAC entity. This type of asynchronous MSDU transfer is performed on a connectionless basis.

[0094] Figure 5 The example format of a PPDU is shown. As shown, a PPDU may contain a PHY preamble, a PHY header, a PSDU, and a tail and padding bits.

[0095] A PSDU may contain one or more MPDUs, such as QoS data frames, MMPDUs, MAC control frames, or QoS empty frames. When an MPDU carries a QoS data frame, the frame body of the MPDU may contain an MSDU or an A-MSDU.

[0096] By default, MSDU delivery is on a best-effort basis. That is, there is no guarantee that the transmitted MSDU will be successfully delivered. However, QoS facilities use Traffic Identifiers (TIDs) to specify differentiated services on a per-MSDU basis.

[0097] The STA can differentiate MSDU delivery based on the specified Traffic Class (TC) or Traffic Flow (TS) of individual MSDUs. The MAC sublayer entity determines the user priority (UP) of the MSDU based on the TID value provided with the MSDU. The QoS facility supports eight UP values. The UP values ​​range from 0 to 7 and form an ordered priority sequence, where 1 is the lowest value, 7 is the highest value, and 0 falls between 2 and 3.

[0098] MSDUs with a specific UP are referred to as belonging to the traffic category with that UP. The UP can be provided directly in the UP parameters at the Media Access Control Service Access Point (MAC SAP) along with each MSDU. Aggregated MPDUs (A-MPDUs) can contain MPDUs with different TID values.

[0099] The STA can deliver Buffer Status Reports (BSRs) to help the AP allocate UL MU resources. The STA can deliver a BSR implicitly in the QoS control field or BSR control subfield of any frame transmitted to the AP (unrequested BSR), or explicitly in a frame sent to the AP in response to a BSRP trigger frame (requested BSR).

[0100] The buffer status reported in the QoS control field includes the queue size value for a given TID. The buffer status reported in the BSR control field includes the ACI bitmap, ΔTID, high-priority AC, and two queue sizes.

[0101] The STA can report the buffer status of transmitted QoS empty frames and QoS data frames to the AP in the QoS control field, and report the buffer status of transmitted QoS empty frames, QoS data frames and management frames to the AP in the BSR control subfield (if present), as defined below.

[0102] The STA can report the queue size for a given TID in the queue size subfield of the QoS control field of the transmitted QoS data frame or QoS empty frame; the STA can set the queue size subfield to 255 to indicate an unknown / unspecified queue size for the TID. The STA can aggregate multiple QoS data frames or QoS empty frames in the A-MPDU to report the queue size for different TIDs.

[0103] If the AP has indicated that it supports the receive BSR control subfield, the STA can report the buffer status in the BSR control subfield of the transmitted frame.

[0104] The High Efficiency (HE) STA can report the queue size of the preferred AC, indicated by the ACI high subfield, in the queue size high subfield of the BSR control subfield. The STA can set the queue size high subfield to 255 to indicate an unknown / unspecified queue size for the AC.

[0105] The HE STA can report the queue size of the AC, as indicated by the ACI bitmap subfield, in the queue size full subfield of the BSR control subfield. The STA can set the queue size full subfield to 255 to indicate those ACs with unknown / unspecified BSRs.

[0106] Triggered TXOP Sharing (TXS) is a technology introduced in the IEEE 802.11be standard revision. TXS allows an AP to allocate a duration within a acquired TXOP to a STA for transmitting one or more non-trigger-based (non-TB) PPDUs. For TXS procedures, the AP can transmit a Multi-User Request to Send (MU-RTS) trigger frame, where the Triggered TXOP Sharing Mode subfield is set to a non-zero value. The MU-RTS trigger frame is used to trigger CTS frames from multiple users. MU-RTS trigger frames with the Triggered TXOP Sharing Mode subfield set to a non-zero value are called MU-RTS TXS Trigger (MRTT) frames.

[0107] In this example, when the Trigger TXOP Share Mode subfield is set to 1, the STA can transmit one or more non-TB PPDUs to the AP during the allocated duration. In this example, when the Trigger TXOP Share Mode subfield is set to 2, the STA can transmit one or more non-TB PPDUs to the AP or a peer STA during the allocated duration. A peer STA can be a STA with a connection for peer-to-peer (P2P) communication or direct communication with another STA. In this example, a direct radio link is established according to the Channel Direct Link Establishment (TDLS) protocol.

[0108] Figure 6 This shows an example MRTT frame 600 that can be used in the TXS program. (Example:) Figure 6 As shown, the instance MRTT frame 600 may include a frame control field, a duration field, a receiver address (RA) field, a transmitter address (TA) field, a public information field, a user information list field, a padding field, and / or a frame check sequence (FCS) field.

[0109] In this example, the public information field can be either the High Efficiency (HE) variant public information field or the Extremely High Throughput (EHT) variant public information field. For example... Figure 6As shown, the EHT variant public information field may include one or more of the following subfields: trigger type, UL length, additional TF, required CS, UL BW, GI and HE / EHT-LTF type / trigger TXOP sharing mode, number of HE / EHT-LTF symbols, LDPC additional symbol fragments, AP Tx power, pre-FEC fill factor, PE ambiguity, UL space reuse, HE / EHT P160, special user information field flag, reserved EHT, reserved or trigger-related public information.

[0110] The trigger type subfield indicates that frame 600 is an MRTT frame.

[0111] The GI and HE / EHT-LTF type / trigger TXOP shared mode subfield may contain a trigger TXOP shared mode subfield. In one instance, the trigger TXOP shared mode subfield can be set to a non-zero value (e.g., 1 or 2). In another instance, the trigger TXOP shared mode subfield can be set to 1. Therefore, the trigger TXOP shared mode subfield can indicate that the STA indicated by the AID12 subfield of the User Information field (of the User Information List field) can transmit one or more non-TB PPDUs to the AP during the time period indicated by the Allocation Duration subfield of the User Information field. In yet another instance, the trigger TXOP shared mode subfield can be set to 2. Therefore, the trigger TXOP shared mode subfield can indicate that the STA indicated by the AID12 subfield of the User Information field (of the User Information List field) can transmit one or more non-TB PPDUs to the AP or to a peer STA during the time period indicated by the Allocation Duration subfield of the User Information field. In one instance, a peer STA can be a STA with a connection for P2P communication or direct communication with the STA.

[0112] The user information list field can contain one or more user information fields. In an example, such as... Figure 6 As shown, the EHT variant user information field may include one or more of the following subfields: AID12, RU allocation, allocation duration, reservation, or PS160.

[0113] The AID12 subfield can indicate the associated identifier (AID) of an STA, which can use the time indicated by the Assigned Duration subfield.

[0114] The RU allocation subfield indicates the location and size of the RU assigned to the STA indicated by the AID12 subfield.

[0115] The allocation duration subfield can indicate the time allocated by the AP transmitting MRTT frame 600. The allocation time can be a portion of the TXOP obtained by the AP. In an example embodiment, the allocation duration subfield can indicate a first time period.

[0116] Figure 7 This shows an example 700 of the TXS program (mode=1). For example... Figure 7 As shown, the TXS procedure can begin with the transmission of MRTT frame 720 from AP 710 to STA 711. MRTT frame 720 can allocate a portion of the TXOP obtained by AP 710 to STA 711 and can indicate a TXS mode equal to 1. STA 711, receiving MRTT frame 720, can use the allocated time to transmit one or more non-TB PPDUs to AP 710. The one or more non-TB PPDUs may include data frames, control frames, management frames, or action frames.

[0117] In this example, the MRTT frame 720 may include a trigger TXOP shared mode subfield indicating the TXS mode and / or a subfield indicating a first time period corresponding to the allocation time. In this example, the first time period may be set to a value of X microseconds (μs).

[0118] STA 711 can respond to MRTT frame 720 by transmitting CTS frame 721 to AP 710. Subsequently, STA 711 can transmit non-TBPPDUs 722, 724, including one or more data frames, to AP 710 during the first time period indicated in MRTT frame 720. In an example, AP 710 can transmit one or more block Ack (BA) frames 723, 725 in response to one or more data frames contained in the non-TBPPDUs 722, 724 received from STA 711.

[0119] Figure 8 This shows an example of a TXS program, 800 (mode=2). For example... Figure 8 As shown, the TXS procedure can begin with the transmission of MRTT frame 820 from AP 810 to STA 811. MRTT frame 820 can allocate a portion of the TXOP obtained by AP 810 to STA 811 and can indicate a TXS mode equal to 2. STA 811, receiving MRTT frame 820, can use the allocated time to transmit one or more non-TB PPDUs to STA 812. The one or more non-TB PPDUs may include data frames, control frames, management frames, or action frames.

[0120] In this example, the MRTT frame 820 may include a trigger TXOP shared mode subfield indicating the TXS mode and / or a subfield indicating a first time period corresponding to the allocation time. In this example, the first time period may be set to a value of X microseconds (μs).

[0121] STA 811 can respond to MRTT frame 820 by transmitting CTS frame 821 to AP 810. Subsequently, STA 811 can transmit non-TBPPDUs 822, 824, including one or more data frames, to STA 818 during the first time period indicated in MRTT frame 820. In an example, STA 812 can transmit one or more BA frames 823, 825 in response to one or more data frames contained in non-TBPPDUs 822, 824 received from STA 811.

[0122] Figure 9 Example multi-AP network 900 is shown. Example multi-AP network 900 can be a multi-AP network according to the Wi-Fi Alliance standard specification for multi-AP networks. For example... Figure 9 As shown, the multi-AP network 900 may include a multi-AP controller 902 and multiple multi-AP groups (or multi-AP sets) 904, 906 and 908.

[0123] The multi-AP controller 902 can be a logical entity that implements the logic for controlling the APs in the multi-AP network 900. The multi-AP controller 902 can receive capability information and measurement results from the APs and can trigger AP control commands and operations on the APs. The multi-AP controller 902 can also provide login functionality to log in and provide access to the multi-AP network 900.

[0124] Multiple AP groups 904, 906, and 908 can each contain multiple APs. APs within a multiple AP group are within each other's communication range. However, APs within a multiple AP group do not need to have the same primary channel. As used herein, the primary channel of an AP refers to the default channel used by the AP to monitor management frames and / or transmit beacon frames. For a STA associated with an AP, the primary channel refers to the AP's primary channel, which is advertised via the AP's beacon frames.

[0125] In one approach, one AP in a multi-AP group can be designated as the master AP. The designation of the master AP can be done by the AP controller 902 or by the APs in the multi-AP group. The master AP in the multi-AP group can be fixed or can change over time among the APs in the group. APs that are not the master APs in the multi-AP group are called slave APs. In one approach, the master AP can be within the communication range of all slave APs in the multi-AP group, and vice versa. A slave AP may be outside the communication range of another slave AP in the multi-AP group.

[0126] In one approach, the APs in a multi-AP group can coordinate with each other, including coordinating transmissions within the multi-AP group. One aspect of this coordination may include coordinating to perform multi-AP transmissions within the multi-AP group. As used herein, multi-AP transmission is a transmission event in which multiple APs (in a multi-AP group or multi-AP network) transmit simultaneously within a time period. The time period for simultaneous AP transmissions can be continuous. Multi-AP transmissions may use different transmission techniques, such as coordinated OFDMA, coordinated spatial multiplexing, joint transmission and reception, coordinated beamforming, and coordinated time division multiple access (TDMA), or a combination of two or more of the foregoing techniques.

[0127] Multi-AP group coordination can be enabled by the AP controller and / or by the primary AP in the multi-AP group. In one approach, the AP controller and / or the primary AP can control time and / or frequency sharing in a TXOP. For example, when one AP in the multi-AP group (e.g., the primary AP) acquires a TXOP, the AP controller and / or the primary AP can control how the time / frequency resources of the TXOP will be shared with other APs in the multi-AP group. In one implementation, the AP in the multi-AP group that acquires the TXOP becomes the primary AP in the multi-AP group. The primary AP can then share a portion (which can be the entire TXOP) of its acquired TXOP with one or more other APs in the multi-AP group.

[0128] OFDMA is a transmission technology introduced in the IEEE 802.11ax standard revision. OFDMA provides a multiple access scheme that allows multiple STAs to simultaneously transmit frames using non-overlapping (orthogonal) frequency subcarriers.

[0129] In Coordinated OFDMA (C-OFDMA), it is conceivable that an AP (e.g., a master AP) can coordinate multi-AP transmissions (which may or may not include a coordinating AP) by allocating appropriate frequency resources (e.g., channels / subchannels) from the available frequency resources to each of the multiple APs during a transmission period. The coordinating AP can further indicate the transmission parameters of the multi-AP transmissions (e.g., PPDU format, guard interval, symbol duration, etc.). During the transmission period, multiple APs simultaneously access the allocated frequency resources using OFDMA. Figure 10 This illustrates C-OFDMA as a multi-AP channel access method, compared to Enhanced Distributed Channel Access (EDCA). For example... Figure 10As shown, in EDCA, channel access for multiple APs (e.g., AP1, AP2) can occur within consecutive time periods (e.g., TXOP). During a given channel access period, the entire channel (e.g., 80 MHz) can be used by a single AP. In contrast, in C-OFDMA, access for multiple APs (multi-AP channel access) can occur within the same time period (e.g., TXOP) on orthogonal frequency resources. For example, as... Figure 10 As shown, an 80 MHz channel can be divided into four non-overlapping 20 MHz channels, each assigned to a corresponding AP among multiple APs. For example, multiple APs can simultaneously transmit to their respective associated STAs within the same time period.

[0130] It is anticipated that future IEEE 802.11 standard drafts will extend the existing TXS procedure described above to APs. In this procedure (hereinafter referred to as the inter-AP TXS procedure), an AP (hereinafter referred to as the sharing AP) may allocate a portion of its acquired TXOP time to one or more other APs (hereinafter referred to as the shared AP). The shared AP can use the allocated time to communicate with its associated STA and / or with the sharing AP without being triggered by the sharing AP. The sharing AP may or may not be part of an AP that communicates during the allocated time.

[0131] Figure 11 Example 1100 of the inter-AP TXS procedure is shown. For example... Figure 11 As shown, instance 1100 includes APs 1102, 1104, 1106, and 1108. In this instance, APs 1102, 1104, 1106, and 1108 can form the configuration described above. Figure 9 This refers to the multi-AP group described herein. In the example, AP 1102 can be the master AP in the multi-AP group, and APs 1104, 1106, and 1108 can be slave APs in the multi-AP group. However, the inter-AP TXS procedure described herein is not limited to use in a multi-AP group and / or in the presence of master and slave APs.

[0132] In Example 1100, AP 1102 can acquire a TXOP. AP 1102 can then initiate an inter-AP TXS operation by transmitting an MRTT frame 1110 to AP 1104. The MRTT frame 1110 can have a format similar to the MU-RTS trigger frame 600 described above. In this example, the MRTT frame 1110 can indicate the identifier of AP 1104 (e.g., in the AID12 subfield of the User Information field of the MRTT frame 1110) and the allocation time 1132 of the TXOP (e.g., in the allocation duration subfield of the User Information field). Additionally, the MRTT frame 1110 can indicate the TXS mode (e.g., in the Triggered TXOP Sharing Mode subfield of the Common Information field of the MRTT frame 1110). The TXS mode can indicate whether AP 1104 should only communicate with AP 1102 during the allocation time 1132 (e.g., when the TXS mode is set to 1), or whether AP 1104 can communicate with AP 1102 or another STA (e.g., an associated non-AP STA or another AP STA) during the allocation time 1132.

[0133] AP 1104 can respond to MRTT frame 1110 by transmitting CTS frame 1112 to AP 1102. Subsequently, for example, during the short inter-frame interval (SIFS) following the transmission of CTS frame 1112, AP 1104 can continue communicating using allocation time 1132 according to the TXS mode indicated in MRTT frame 1110 without triggering from AP 1102. In instance 1100, TXS mode allows AP 1104 to communicate with AP 1102 or with another STA during allocation time 1132. Therefore, as Figure 11 As shown, AP 1104 can use allocation time 1132 to send to the associated STA ( Figure 11 (Not shown in the text) Transmission (non-TB) downlink (DL) PPDU 1114, and from the associated STA ( Figure 11 (Not shown in the image) Receive uplink (UL) PPDU 1116.

[0134] In this example, utilizing the remaining time of the TXOP, AP 1102 can initiate another inter-AP TXS operation by transmitting MRTT frame 1118 to APs 1106 and 1108. MRTT frame 1118 can have a format similar to the MU-RTS trigger frame 600 described above. In this example, MRTT frame 1118 can indicate the identifiers of APs 1106 and 1108 (e.g., in the corresponding AID12 subfield of the corresponding user information field of MRTT frame 1118) and the allocation time 1134 of the TXOP (e.g., in the corresponding allocation duration subfield of the user information field). Additionally, MRTT frame 1118 can indicate the TXS mode (e.g., in the trigger TXOP sharing mode subfield of the common information field of MRTT frame 1118). The TXS mode can indicate whether AP 1106 and 1108 should only communicate with AP 1102 during allocation time 1134 (e.g., when TXS mode is set to 1), or whether AP 1106 and 1108 can communicate with AP 1102 or other STAs (e.g., associated non-AP STAs or another AP STA) during allocation time 1134.

[0135] APs 1106 and 1108 can respond to MRTT frame 1118 by transmitting CTS frames 1120 and 1122 to AP 1102, respectively. Subsequently, for example, at SIFS after transmitting CTS frames 1120 and 1122, APs 1106 and 1108 can continue communicating using allocation time 1134 according to the TXS mode indicated in MRTT frame 1118 without a trigger from AP 1102. In instance 1100, the TXS mode allows APs 1106 and 1108 to communicate with AP 1102 or with another STA during allocation time 1134. Therefore, as... Figure 11 As shown, AP 1104 can use allocation time 1134 to send to the associated STA ( Figure 11 Transmit (non-TB) DL PPDU 1124 from the associated STA (not shown in the image) and from the associated STA ( Figure 11 (Not shown in the image) receives UL PPDU 1128. Similarly, AP 1108 can use allocation time 1134 to send to the associated STA ( Figure 11 (Not shown in the text) Transmission (non-TB) DL PPDU1126, and from the associated STA ( Figure 11 (Not shown in the image) Receives UL PPDU 1130.

[0136] In this example, C-OFDMA can be used for the transmission of DL PPDU 1124 and 1126, and UL PPDU 1128 and 1130. Specifically, AP 1102 can allocate corresponding frequency resources orthogonal to each other to AP 1106 and 1108 within allocation time 1134. For example, AP 1102 can divide an 80 MHz channel into two non-overlapping 40 MHz channels, each allocated to one of the corresponding APs, AP 1106 and 1108. In this example, the frequency resources allocated to the APs are indicated in the RU allocation subfield of the user information field (which indicates the identifier of the AP) of MRTT frame 1118. Therefore, DL PPDU 1124 and UL PPDU 1128 can be transmitted on RUs orthogonal to the RUs used for the transmission of DL PPDU 1126 and UL PPDU 1130.

[0137] Figure 12 Example PPDU 1200 is shown, which can be used for downlink DL PPDU or UL PPDU. For example, PPDU 1200 can be... Figure 11 The embodiments described herein include DL PPDU 1114, 1124, or 1126, or UL PPDU 1116, 1128, or 1130. PPDU 1200 may be an Ultra-High Reliability (UHR) PPDU usable by a device conforming to the IEEE 802.11bn standard amendment. Such devices can operate in the 2.4, 5, and 6 GHz frequency bands. In embodiments, PPDU 1200 can transmit over a bandwidth of up to 320 MHz. PPDU 1200 can be used by a device for both single-user (SU) and multi-user (MU) transmission. It should be noted that UHR may be referred to by different names (e.g., Ultra-High Throughput (UHR) or Ultra-High Efficiency (UHE)).

[0138] like Figure 12 As shown, the PPDU 1200 includes a non-HT short training field (L-STF), a non-HT long training field (L-LTF), a non-high throughput (non-HT) signal field (L-SIG), a non-HT repetitive signal field (RL-SIG), a universal signal field (U-SIG), a UHR signal field (UHR-SIG), a UHR short training field (UHR-STF), one or more UHR long training fields (UHR-LTF), a data field, and a packet extension (PE) field.

[0139] The L-STF is used by the receiver of the PPDU 1200 to synchronize with the carrier frequency and frame timing of the PPDU 1200 transmitter and to adjust the receiver signal gain.

[0140] The L-LTF is used by the receiver of the PPDU 1200 to estimate the channel coefficients in order to equalize the channel response (e.g., amplitude and phase distortion) in both the signal field (L-SIG, RL-SIG, U-SIG, UHR-SIG) and the data field of the PPDU 1200.

[0141] L-SIG and RL-SIG contain the parameters required for demodulating the data field. The L-SIG can be equalized using channel coefficients estimated with L-LTF, and the L-SIG can be demodulated to obtain the demodulation parameters for the data field.

[0142] U-SIG ensures the forward compatibility of PPDU 1200. This means that any future PPDU that is backward compatible with IEEE 802.11bn will contain the same U-SIG field. Therefore, devices compliant with IEEE 802.11bn will be able to understand PPDUs developed in future amendments, provided that those amendments also contain the U-SIG field.

[0143] The UHR-SIG contains an indication of the resource unit (RU) allocation for each STA. The receiving STA can use the indication in the UHR-SIG to locate its payload in the data field of the PPDU 1200.

[0144] The L-SIG, RL-SIG, U-SIG, and UHR-SIG fields can be considered as the PHY header of the PPDU 1200.

[0145] UHR-STF and one or more UHR-LTFs are provided by the receiver of PPDU 1200 to estimate channel coefficients in order to equalize the channel response (e.g., amplitude and phase distortion) in the data field of PPDU 1200.

[0146] The data field contains one or more payloads carried by the PPDU 1200. One or more payloads may include an MPDU.

[0147] The PE field is an extension of the PPDU 1200, designed to give the receiver of the PPDU 1200 sufficient time to respond after receiving the PPDU 1200.

[0148] Figure 13 To show Figure 11 Example 1300 shows a potential problem in the AP-to-TXS procedure. For example... Figure 13As shown, Example 1300 includes APs 1102, 1106, and 1108 as described above. As in Example 1100, AP 1102 initiates an inter-AP TXS operation by transmitting MRTT frame 1118 to APs 1106 and 1108. MRTT frame 1118 may have a format similar to the MU-RTS trigger frame 600 described above. In this example, MRTT frame 1118 may indicate the identifiers of APs 1106 and 1108 (e.g., in the corresponding AID12 subfield of the corresponding user information field of MRTT frame 1118) and the allocation time 1134 of the TXOP (e.g., in the corresponding allocation duration subfield of the user information field). Additionally, MRTT frame 1118 may indicate the TXS mode (e.g., in the trigger TXOP sharing mode subfield of the common information field of MRTT frame 1118). The TXS mode can indicate whether AP1106 and 1108 should only communicate with AP1102 during allocation time 1134 (e.g., when TXS mode is set to 1), or whether AP1106 and 1108 can communicate with AP1102 or other STAs (e.g., associated non-AP STAs or another AP STA) during allocation time 1134.

[0149] APs 1106 and 1108 respond to MRTT frame 1118 by transmitting CTS frames 1120 and 1122 to AP 1102, respectively. Subsequently, for example, at SIFS after transmitting CTS frames 1120 and 1122, APs 1106 and 1108 can continue communicating using allocation time 1134 according to the TXS mode indicated in MRTT frame 1118 without a trigger from AP 1102. In instance 1300, the TXS mode allows APs 1106 and 1108 to communicate with AP 1102 or with another STA during allocation time 1134. Therefore, as... Figure 13 As shown, AP 1104 can use allocation time 1134 to send to the associated STA ( Figure 13 (Not shown in the image) Transmits DL PPDU 1302 and from the associated STA ( Figure 13 (Not shown in the image) receives UL PPDU 1306. Similarly, AP1108 can use allocation time 1134 to send to the associated STA ( Figure 13 (Not shown in the text) Transmit DL PPDU 1304, and from the associated STA ( Figure 13 (Not shown in the text) Receives UL PPDU 1308.

[0150] In this example, C-OFDMA can be used for the transmission of DL PPDU 1302 and 1304, and UL PPDU 1306 and 1308. Specifically, AP 1102 can allocate corresponding frequency resources orthogonal to each other to AP 1106 and 1108 within allocation time 1134. For example, AP 1102 can divide an 80 MHz channel into two non-overlapping 40 MHz channels, each allocated to one of the corresponding APs, AP 1106 and 1108. In this example, the frequency resources allocated to the AP are indicated in the RU allocation subfield of the user information field (which indicates the identifier of the AP) of MRTT frame 1118. Therefore, DL PPDU 1302 and UL PPDU 1306 can be transmitted on RUs orthogonal to the RUs used for the transmission of DL PPDU 1304 and UL PPDU 1308.

[0151] Since APs 1106 and 1108 were not triggered by AP 1102 during allocation time 1134, AP 1102 can indicate a first time period within allocation time 1134 for DL ​​transmission and / or a second time period within allocation time 1134 for UL transmission in MRTT frame 1118. APs 1106 and 1108 can use the first time period to transmit DL PPDUs 1302 and 1304, respectively. Similarly, APs 1106 and 1108 can use the second time period to receive UL PPDUs 1306 and 1308, respectively. The first and second time periods facilitate the timing alignment of DL PPDUs 1302 and 1304, and UL PPDUs 1306 and 1308, as follows: Figure 13 As shown, this reduces potential OFDM symbol misalignment at the receiver receiving one of PPDUs 1302, 1304, 1306, or 1308. OFDM symbol misalignment causes a desynchronization between the boundaries of OFDM symbols received on a first portion of the channel (e.g., the first 40 MHz) and the boundaries of corresponding OFDM symbols received on a second portion of the channel (e.g., the second 40 MHz). Since the receiver typically receives and processes the entire channel (in the absence of dedicated receive filters for each sub-channel), the receiver may be unable to decode PPDUs where OFDM symbol misalignment occurs.

[0152] In one implementation, DL PPDUs 1302 and 1304 may each include a corresponding trigger frame. In another implementation, the trigger frame included in DL PPDU 1302 triggers one or more STAs associated with AP 1106 to perform a UL transmission to AP 1106. The length / size of the trigger frame included in DL PPDU 1302 depends on the total number of STAs associated with AP 1106 triggered by the trigger frame. The UL transmission can be a C-OFDMA transmission to AP 1106 performed by multiple STAs. In one example, the UL transmission may be performed via UL PPDU 1306 within a second time period indicated in MRTT frame 1118. In another implementation, the trigger frame included in DL PPDU 1304 triggers one or more STAs associated with AP 1108 to perform a UL transmission to AP 1108. The length / size of the trigger frame included in DL PPDU 1304 depends on the total number of STAs associated with AP 1108 triggered by the trigger frame. UL transmissions can be C-OFDMA transmissions to AP 1108 performed by multiple STAs. In an example, a UL transmission can be performed via UL PPDU 1308 within the second time period indicated in MRTT frame 1118.

[0153] In the implementation, AP 1102 may have information about the amount of downlink data that each of APs 1106 and 1108 intends to transmit in DLPPDUs 1302 and 1304, respectively. AP 1102 may take this information into account when setting a first time period for DLPPDUs 1302 and 1304. However, without knowing the characteristics of the uplink data that each of APs 1106 and 1108 intends to receive during UL transmission (e.g., in UL PPDUs 1306 and 1308, respectively), the first time period may not take into account the desired / expected length of the trigger frame included in DLPPDU 1304 and / or the desired / expected length of the trigger frame included in DLPPDU 1304. For example, as Figure 13As shown, AP 1102 can set the first time period in a manner that substantially exceeds the necessary length of the corresponding trigger frames included in DL PPDUs 1302 and 1304. Therefore, both APs 1106 and 1108 may have to pad DL PPDUs 1302 and 1304 to time-align them. This could result in wasted resources allocated for downlink transmissions. In another instance, the first time period may be too short for DL ​​PPDU 1302 to contain a corresponding trigger frame of appropriate length / size for triggering one or more STAs associated with AP 1106. Alternatively or additionally, the first time period may be too short for DL ​​PPDU 1304 to contain a corresponding trigger frame of appropriate length / size for triggering one or more STAs associated with AP 1108. Therefore, resources allocated for UL transmissions (e.g., for UL PPDU 1306 and / or UL PPDU 1308) may be partially unused because AP 1106 and / or AP 1108 may not be able to trigger all STAs intended to be transmitted during UL transmissions.

[0154] As further described below, embodiments of this disclosure address the aforementioned problems that may arise in inter-AP TXS procedures. In one aspect, a first AP may transmit a first frame to a second AP, the first frame indicating the number of STAs performing a UL transmission to the first AP. The number of STAs indicated in the first frame may be STAs that the first AP wishes to receive from it in the UL transmission. STAs may be associated with the first AP. The first AP may be a shared AP, and the second AP may be a shared AP. The UL transmission may be part of a coordinated transmission. The coordinated transmission may include another UL transmission to the second AP or to a third AP. The coordinated transmission may be a C-OFDMA transmission. The coordinated transmission may be performed within the allocated time of the TXOP obtained by the second AP. The second AP may transmit a second frame to the first AP, the second frame indicating a time period for a DL PPDU, the DL PPDU including a trigger frame for the STA. The trigger frame triggers the STA to perform a UL transmission. In an embodiment, the time period is based on the number of STAs indicated in the first frame. In an embodiment, the time period is within the allocated time of the TXOP. In another embodiment, the first AP may transmit a first frame to the second AP, the first frame indicating a first length (e.g., number of bytes) of a trigger frame for transmission by the first AP to one or more STAs in a DL PPDU. One or more STAs may be associated with the first AP. The first AP may receive a second frame from the second AP indicating the duration of the DL PPDU. The duration may be within the allocated time of a TXOP obtained by the second AP. In one embodiment, the duration is based on the first length of the trigger frame. In another embodiment, the duration is based on a second length of the trigger frame. The second length may be based on the first length. Other aspects and details of the embodiments are presented in the exemplary embodiments described below.

[0155] Figure 14 Example 1400 of an inter-AP TXS procedure according to an embodiment is shown. For example... Figure 14 As shown, instance 1400 includes APs 1402, 1404, and 1406. In this instance, APs 1402, 1404, and 1406 can form the configuration described above. Figure 9 The document describes a multi-AP group. In this example, AP 1402 can be the shared AP (or master AP) in the multi-AP group, and APs 1404 and 1406 can be the shared APs (or slave APs) in the multi-AP group. However, the inter-AP TXS procedure described herein is not limited to use in a multi-AP group and / or in the presence of a shared AP (or master AP) and a shared AP (or slave AP).

[0156] like Figure 14As shown, Example 1400 may begin with AP 1404 transmitting frame 1408 to AP 1402. In this embodiment, frame 1408 may indicate the number of STAs performing uplink (UL) transmissions to AP 1404. The number of STAs indicated in frame 1408 may be associated with AP 1404. The number of STAs indicated in frame 1408 may be STAs that AP 1404 intends or wishes to receive from it in UL transmissions. The number of STAs indicated in frame 1408 may be scheduled by AP 1404 for UL transmissions. UL transmissions may be part of coordinated transmissions. Coordinated transmissions may be performed within the allocated time of a TXOP obtained by the second AP 1402. Coordinated transmissions may be performed within the context of an inter-AP TXS procedure as described above. Coordinated transmissions may or may not include transmissions to AP 1402. Coordinated transmissions may include transmissions to AP 1402 and one or more of APs 1404 and 1406. Alternatively, such as Figure 14 As shown, coordinated transmissions may include transmissions to APs 1404 and 1406. Coordinated transmissions may include C-OFDMA transmissions, coordinated spatial multiplexing (C-SR) transmissions, coordinated beamforming (C-BF) transmissions, or coordinated joint transmissions.

[0157] In another embodiment, frame 1408 may indicate a first length / size (e.g., number of bytes) of a trigger frame for transmission by AP 1404 to one or more STAs in a DL PPDU. One or more STAs may be associated with AP 1404. The one or more STAs may be STAs that AP 1404 intends or wishes to receive from it in a UL transmission. UL transmission from one or more STAs may follow a transmission of the DL PPDU performed by AP 1404. UL transmission from one or more STAs may be triggered by a trigger frame included in the DL PPDU. The first length / size of the trigger frame may be preferred / recommended / selected by AP 1404. The first length / size may be based on the total number of one or more STAs.

[0158] In an embodiment, for example, frame 1408 may be a QoS data frame / empty frame or an action frame. When frame 1408 is a QoS data / empty frame, the QoS data / empty frame may include an aggregation control (A-Control) field, which includes the number of STAs and / or the first length / size of the trigger frame, for example, as... Figure 16 As shown in the diagram. When frame 1408 is an action frame, the action frame may include information elements (or information fields), which include the number of STAs and / or the first length / size of the trigger frame. For example, the information elements are in Figure 17 As shown in the image.

[0159] In an embodiment, frame 1408 may further include a Buffer Status Report (BSR). The BSR may indicate the amount of traffic buffered for DL ​​transmissions at AP 1404. In an embodiment, the buffered traffic may correspond to all traffic buffered for DL ​​transmissions at AP 1404. In another embodiment, the BSR may indicate the amount of traffic buffered for UL transmissions to AP 1404. In an embodiment, the buffered traffic may correspond to all traffic buffered for UL transmissions to AP 1404 (from all STAs associated with AP 1404). In another embodiment, the buffered traffic may correspond to traffic buffered for UL transmissions from STAs to AP 1404, with the number of STAs indicated in frame 1408. In an embodiment, the buffered traffic may correspond to traffic buffered for DL / UL transmissions for a specific Access Class (AC) or TID. The BSR may indicate as referenced above. Figure 4 The amount of buffered traffic described (e.g., in the queue size subfield).

[0160] In this example, instance 1400 may also include AP 1406 transmitting frame 1410 to AP 1402. Frame 1410 may be transmitted before or after frame 1408. In this embodiment, frame 1410 may indicate the number of STAs performing UL transmissions to AP 1406. The number of STAs indicated in frame 1410 may be associated with AP 1406. The number of STAs indicated in frame 1410 may be STAs that AP 1406 intends or wishes to receive from it in UL transmissions. The number of STAs indicated in frame 1410 may be scheduled by AP 1406 for UL transmissions. UL transmissions to AP 1406 may be part of a coordinated transmission that includes UL transmissions to AP 1404. Frame 1410 is similar to frame 1408. The same description above regarding frame 1408 applies to frame 1410.

[0161] Subsequently, AP 1402 can obtain a TXOP and initiate an inter-AP TXS operation by transmitting MRTT frame 1412 to APs 1404 and 1406. MRTT frame 1412 may have a format similar to the MU-RTS trigger frame 600 described above. In an example, MRTT frame 1412 may indicate the identifiers of APs 1404 and 1406 (e.g., in the corresponding AID12 subfield of the corresponding user information field of MRTT frame 1412). Additionally, MRTT frame 1412 may indicate the TXS mode (e.g., in the trigger TXOP sharing mode subfield of the common information field of MRTT frame 1412) and the TXOP allocation time 1414 (e.g., in the corresponding allocation duration subfield of the user information field). The TXS mode can indicate whether AP 1404 and 1406 should communicate with AP 1402 only during allocation time 1414 (e.g., when TXS mode is set to 1), or whether AP 1404 and 1406 can communicate with AP 1402 or other STAs (e.g., associated non-AP STAs or another AP STA) during allocation time 1414.

[0162] In an embodiment, MRTT frame 1412 may further indicate a time period 1428 within allocated time 1414 for DL ​​transmissions by AP 1404 and / or AP 1406. In an embodiment, time period 1428 may be configured to accommodate the transmission of a first DL PPDU by AP 1404. The first DL PPDU may include one or more data frames to one or more STAs associated with AP 1404 and / or trigger frames for the STAs, the number of STAs being indicated by AP 1404 in frame 1408. In an embodiment, time period 1428 may be further configured to accommodate the transmission of a second DL PPDU by AP 1406. The second DL PPDU may include one or more data frames to one or more STAs associated with AP 1406 and / or trigger frames for the STAs, the number of STAs being indicated by AP 1406 in frame 1410. The first DL PPDU and the second DL PPDU may be intended for parallel transmission (e.g., C-OFDMA transmission).

[0163] In an embodiment, time period 1428 may be based on the number of STAs indicated in frame 1408 and / or the number of STAs indicated in frame 1410.

[0164] In an embodiment, MRTT frame 1412 may alternatively or additionally indicate a time period 1430 for trigger frames included in DL transmissions performed by AP 1404 and / or AP 1406. Time period 1430 may be within time period 1428. In an embodiment, time period 1430 may be based on the number of STAs indicated in frame 1408 and / or the number of STAs indicated in frame 1410.

[0165] In one embodiment, AP 1402 may determine a first length / size of the DL transmission (and / or the trigger frame included in the DL transmission) based on the number of STAs indicated in frame 1408. In another embodiment, the first length / size may be further based on the number of data frames that AP 1404 intends to transmit in the first DL PPDU and / or the number of STAs that AP 1404 intends to serve by the first DL PPDU. In another embodiment, AP 1402 may determine a second length / size of the DL transmission (and / or the trigger frame included in the DL transmission) based on the number of STAs indicated in frame 1410. In yet another embodiment, the second length / size may be further based on the number of data frames that AP 1406 intends to transmit in the second DL PPDU and / or the number of STAs that AP 1406 intends to serve by the second DL PPDU. In an example, based on the number of STAs indicated in frames 1408 / 1410, AP 1402 may determine the length / size of a field (e.g., a user information field) of the trigger frame, which is required to trigger the indicated STA to perform a UL transmission. Fields may include user-specific fields. The number of fields within a trigger frame may vary depending on the number of STAs triggered by the trigger frame.

[0166] In one embodiment, AP 1402 may determine a first duration based on a first length / size. In another embodiment, AP 1402 may determine a second duration based on a second length / size. In yet another embodiment, AP 1402 may select the larger of the first and second durations as time period 1428 (or time period 1430). This ensures that time period 1428 (or time period 1430) is long enough to accommodate the corresponding trigger frames of both APs 1404 and 1406. In yet another embodiment, AP 1402 may select the shorter of the first and second durations as time period 1428 (or time period 1430). This ensures that time period 1428 can be fully utilized by at least one of APs 1404 and 1406.

[0167] In another embodiment, time period 1428 (and / or time period 1430) may be based on a first length / size of the trigger frame indicated in frame 1408 and / or a first length / size of the trigger frame indicated in frame 1410. In an embodiment, AP1402 may determine a second length / size of the trigger frame based on the first length / size indicated in frame 1408 and / or the first length / size indicated in frame 1410. In an embodiment, time period 1428 (and / or time period 1430) may be based on the second length / size.

[0168] In an embodiment, MRTT frame 1412 may include the duration of time period 1428 (and / or time period 1430). In an embodiment, the start time of time period 1428 (and / or time period 1430) may be determined based on MRTT frame 1412. For example, the start time of time period 1428 may be 2 SIFS plus the CTS frame transmission time from the time MRTT frame 1412 is received. The end time of time period 1428 may be determined based on the start time and the indicated duration. The start time of time period 1430 may be based on the start time of time period 1428 (e.g., X microseconds from the start time of time period 1428). The end time of time period 1430 may be determined based on the start time of time period 1430 and the indicated duration of time period 1430.

[0169] In another embodiment, MRTT frame 1412 may include the start and end times of time period 1428 (and / or time period 1430), the start time and duration of time period 1428 (and / or time period 1430), or the duration and end time of time period 1428 (and / or time period 1430). In such embodiments, the start time of time period 1428 (and / or time period 1430) may not be based on MRTT frame 1412.

[0170] In another embodiment, MRTT frame 1412 may indicate time period 1428 (and / or time period 1430) as a segment of allocated time 1414. For example, MRTT frame 1412 may indicate that time period 1428 corresponds to the first half / third / quarter of allocated time 1414, or the first X microseconds of allocated time 1414, etc. For example, MRTT frame 1412 may indicate that time period 1430 corresponds to the last half / third / quarter of allocated time 1414, or the last X microseconds of allocated time 1414, etc.

[0171] In other embodiments, AP 1402 may initiate inter-AP TXS operation by transmitting frames other than MRTT frames. For example, AP 1402 may use multiple AP trigger frames to initiate inter-AP TXS operation. Multiple AP trigger frames may include / indicate the same information as described above, which is included / indicated in MRTT frame 1412. APs 1404 and 1406 may or may not respond to, acknowledge or not acknowledge, the multiple AP trigger frames from AP 1402.

[0172] like Figure 14 As shown, APs 1404 and 1406 can respond to MRTT frame 1412 by transmitting CTS frames 1416 and 1418 to AP 1402, respectively. Subsequently, for example, at SIFS after transmitting CTS frames 1416 and 1418, APs 1404 and 1406 can continue to communicate using allocated time 1414 according to the TXS mode indicated in MRTT frame 1412, taking into account time period 1428 (and / or time period 1430), without triggering from AP 1402. In instance 1400, the TXS mode allows APs 1404 and 1406 to communicate with AP 1402 or with another STA during allocated time 1414. Therefore, as Figure 14 As shown, AP 1404 can use the time period 1428 of the allocation time 1414 to send to the associated STA ( Figure 14 (Not shown in the diagram) Transmit (non-TB) DL PPDU 1420. DL PPDU 1420 may include a trigger frame, the length / size of which is determined by time period 1428 (and / or time period 1430). In an example, AP 1404 may use time period 1430 to transmit the trigger frame included in DL PPDU 1420. Similarly, as Figure 14 As shown, AP 1406 can use the time period 1428 of the allocated time 1414 to send to the associated STA ( Figure 14 (Not shown in the image) Transmission (non-TB) DL PPDU 1422. DL PPDU 1422 may include a trigger frame whose length / size is determined by time period 1428 (and / or time period 1430). In the example, AP 1406 may use time period 1430 to transmit the trigger frame included in DL PPDU 1422.

[0173] In Example 1400, the combined length / size of one or more data frames and trigger frames to be transmitted by AP 1404 in DL PPDU 1420 can be greater than the combined length / size of one or more data frames and trigger frames to be transmitted by AP 1406 in DL PPDU 1422. In this example, AP 1402 can set time period 1428 based on the combined length / size of one or more data frames and trigger frames to be transmitted by AP 1404 in DL PPDU 1420. For example, AP 1404 can set a first time period 1428 equal to the combined length / size of one or more data frames and trigger frames to be transmitted by AP 1404 in DL PPDU 1420. Therefore, as Figure 14 As shown, AP 1404 does not need to insert any padding bits in DL PPDU 1420 and can utilize the entire time period 1428 to transmit data / control information. Therefore, the utilization of allocation time 1414, and especially time period 1428, is increased. Since the combined length / size of one or more data frames and trigger frames to be transmitted by AP 1406 in DL PPDU 1422 is shorter than time period 1428, AP 1406 can insert padding bits into DL PPDU 1422. Padding bits can be inserted before or after the trigger frames included in DL PPDU 1422.

[0174] In an example, AP 1404 may use the remaining duration of allocation time 1414 to draw from one or more associated STAs, based on any indication in MRTT frame 1412. Figure 14 (Not shown in the image) Receives UL PPDU 1424. In this example, AP1406 may use the remaining duration of allocation time 1414 to receive data from one or more associated STAs, based on any indication in MRTT frame 1412. Figure 14 (Not shown) Receives UL PPDU 1426. In an embodiment, as described above, frame 1412 may further indicate the time period for UL PPDUs 1424 and 1426. In an embodiment, AP 1404 may signal the time period to one or more associated STAs scheduled to transmit UL PPDU 1424. In an embodiment, AP 1406 may signal the time period to one or more associated STAs scheduled to transmit UL PPDU 1426.

[0175] In this example, C-OFDMA can be used for the transmission of DL PPDU 1420 and 1422, and UL PPDU 1424 and 1426. Specifically, AP 1402 can allocate corresponding frequency resources orthogonal to each other to AP 1404 and 1406 within allocation time 1414. For example, AP 1402 can divide an 80 MHz channel into two non-overlapping 40 MHz channels, each allocated to one of the corresponding APs, AP 1404 and 1406. In this example, the frequency resources allocated to the AP are indicated in the RU allocation subfield of the user information field (which indicates the identifier of the AP) of MRTT frame 1412. Therefore, DL PPDU 1420 and UL PPDU 1424 can be transmitted on RUs orthogonal to the RUs used for the transmission of DL PPDU 1422 and UL PPDU 1426.

[0176] Figure 15 Example 1500 of an inter-AP TXS procedure according to another embodiment is shown. Figure 15 As shown in the example, Example 1500 also includes the references above. Figure 15 The described APs are 1402, 1404, and 1406. In practice, APs 1402, 1404, and 1406 can form the configuration described above. Figure 9 The document describes a multi-AP group. In this example, AP 1402 can be the shared AP (or master AP) in the multi-AP group, and APs 1404 and 1406 can be the shared APs (or slave APs) in the multi-AP group. However, the inter-AP TXS procedure described herein is not limited to use in a multi-AP group and / or in the presence of a shared AP (or master AP) and a shared AP (or slave AP).

[0177] like Figure 15 As shown, Example 1500 may begin with AP 1402 transmitting frame 1502 to AP 1404 and / or AP 1406. In this embodiment, frame 1502 requests a BSR from AP 1404 and / or AP 1406 for coordinated transmission. The coordinated transmission may be performed within the allocated time of the TXOP obtained by the second AP 1402. The coordinated transmission may be performed within the context of the inter-AP TXS procedure described above. The coordinated transmission may include coordinated DL transmissions and / or coordinated UL transmissions. The coordinated transmission may or may not include transmissions from / to AP 1402. The coordinated transmission may include transmissions from / to AP 1402 and transmissions from / to one or more of APs 1404 and 1406. Alternatively, as... Figure 15As shown, coordinated transmissions may include DL transmissions performed by APs 1404 and 1406, as well as UL transmissions to and from APs 1404 and 1406. Coordinated transmissions may include C-OFDMA transmissions, Coordinated Spatial Multiplexing (C-SR) transmissions, Coordinated Beamforming (C-BF) transmissions, or Coordinated Joint Transmissions. Frame 1502 may include a Buffer Status Report Polling (BSRP) triggered frame, a basic triggered frame, a polling frame, or a request frame.

[0178] In one embodiment, AP 1404 may respond to frame 1502 by transmitting frame 1504 to AP 1402. In one embodiment, frame 1504 includes a BSR for coordinated transmission. The BSR may indicate the amount of traffic buffered for DL ​​transmissions at AP 1404. In one implementation, the buffered traffic may correspond to all traffic buffered for DL ​​transmissions at AP 1404. In another embodiment, the BSR may indicate the amount of traffic buffered for UL transmissions to AP 1404. In one implementation, the buffered traffic may correspond to all traffic buffered for UL transmissions to AP 1404 (from all STAs associated with AP 1404). In one implementation, the buffered traffic may correspond to traffic buffered for DL / UL transmissions for a specific Access Class (AC) or TID. The BSR may indicate as referenced above. Figure 4 The amount of buffered traffic described (e.g., in the queue size subfield).

[0179] In an embodiment, frame 1504 may additionally or alternatively indicate the number of STAs performing UL transmissions to AP 1404. The number of STAs indicated in frame 1504 may be associated with AP 1404. The number of STAs indicated in frame 1504 may be STAs that AP 1404 intends or wishes to receive from it in UL transmissions. The number of STAs indicated in frame 1504 may be scheduled by AP 1404 for UL transmissions. UL transmissions to AP 1404 may be part of a coordinated transmission indicated in frame 1502.

[0180] In another embodiment, frame 1504 may indicate a first length / size (e.g., number of bytes) of a trigger frame for transmission by AP 1404 to one or more STAs in a DL PPDU. One or more STAs may be associated with AP 1404. The one or more STAs may be STAs that AP 1404 intends or wishes to receive from it in a UL transmission. UL transmissions from one or more STAs may follow transmissions of the DL PPDU performed by AP 1404. UL transmissions from one or more STAs may be triggered by a trigger frame included in the DL PPDU. The first length / size of the trigger frame may be preferred / recommended / selected by AP 1404. The first length / size may be based on the total number of one or more STAs.

[0181] In an embodiment, for example, frame 1504 may be a QoS data / empty frame or an action frame. When frame 1504 is a QoS data / empty frame, the QoS data / empty frame may include an aggregation control (A-Control) field, which includes the number of STAs and / or the first length / size of the trigger frame, for example, as... Figure 16 As shown in the diagram. When frame 1504 is an action frame, the action frame may include information elements (or information fields), which include the number of STAs and / or the first length / size of the trigger frame. For example, the information elements in... Figure 17 As shown in the image.

[0182] In this example, example 1500 may also include AP 1406 transmitting frame 1506 to AP 1402. Frame 1506 may be transmitted before or after frame 1504. In this embodiment, frame 1506 may indicate the number of STAs performing UL transmissions to AP 1406. The number of STAs indicated in frame 1506 may be associated with AP 1406. The number of STAs indicated in frame 1506 may be STAs that AP 1406 intends or wishes to receive from it in UL transmissions. The number of STAs indicated in frame 1506 may be scheduled by AP 1406 for UL transmissions. UL transmissions to AP 1406 may be part of a coordinated transmission that includes UL transmissions to AP 1404. Frame 1506 is similar to frame 1408. The same description above regarding frame 1408 applies to frame 1506.

[0183] Subsequently, AP 1402 can obtain a TXOP and initiate an inter-AP TXS operation by transmitting an MRTT frame 1508 to APs 1404 and 1406. The MRTT frame 1508 may have a format similar to the MU-RTS trigger frame 600 described above. In an example, the MRTT frame 1508 may indicate the identifiers of APs 1404 and 1406 (e.g., in the corresponding AID12 subfield of the corresponding user information field of the MRTT frame 1508). Additionally, the MRTT frame 1508 may indicate the TXS mode (e.g., in the trigger TXOP sharing mode subfield of the common information field of the MRTT frame 1508) and the TXOP allocation time 1510 (e.g., in the corresponding allocation duration subfield of the user information field). The TXS mode can indicate whether AP 1404 and 1406 should communicate with AP 1402 only during allocation time 1510 (e.g., when TXS mode is set to 1), or whether AP 1404 and 1406 can communicate with AP 1402 or other STAs (e.g., associated non-AP STAs or another AP STA) during allocation time 1510.

[0184] In an embodiment, MRTT frame 1508 may further indicate a time period 1524 within allocated time period 1510 for DL ​​transmissions by AP 1404 and / or AP 1406. In an embodiment, time period 1524 may be configured to accommodate the transmission of a first DL PPDU by AP 1404. The first DL PPDU may include one or more data frames to one or more STAs associated with AP 1404 and / or trigger frames for the STAs, the number of STAs being indicated by AP 1404 in frame 1504. In an embodiment, time period 1524 may be further configured to accommodate the transmission of a second DL PPDU by AP 1406. The second DL PPDU may include one or more data frames to one or more STAs associated with AP 1406 and / or trigger frames for the STAs, the number of STAs being indicated by AP 1406 in frame 1506. The first DL PPDU and the second DL PPDU may be intended for parallel transmission (e.g., C-OFDMA transmission).

[0185] In an embodiment, time period 1524 may be based on the number of STAs indicated in frame 1504 and / or the number of STAs indicated in frame 1506.

[0186] In an embodiment, MRTT frame 1508 may alternatively or additionally indicate a time period 1526 for trigger frames included in DL transmissions performed by AP 1404 and / or AP 1406. Time period 1526 may be within time period 1524. In an embodiment, time period 1526 may be based on the number of STAs indicated in frame 1504 and / or the number of STAs indicated in frame 1506.

[0187] In one embodiment, AP 1402 may determine a first length / size of the DL transmission (and / or the trigger frame included in the DL transmission) based on the number of STAs indicated in frame 1504. In another embodiment, the first length / size may be further based on the number of data frames that AP 1404 intends to transmit in the first DL PPDU and / or the number of STAs that AP 1404 intends to serve by the first DL PPDU. In another embodiment, AP 1402 may determine a second length / size of the DL transmission (and / or the trigger frame included in the DL transmission) based on the number of STAs indicated in frame 1506. In yet another embodiment, the second length / size may be further based on the number of data frames that AP 1406 intends to transmit in the second DL PPDU and / or the number of STAs that AP 1406 intends to serve by the second DL PPDU. In an example, based on the number of STAs indicated in frames 1504 / 1506, AP 1402 may determine the length / size of a field (e.g., a user information field) of the trigger frame, which is required to trigger the indicated STA to perform a UL transmission. Fields may include user-specific fields. The number of fields within a trigger frame may vary depending on the number of STAs triggered by the trigger frame.

[0188] In one embodiment, AP 1402 may determine a first duration based on a first length / size. In another embodiment, AP 1402 may determine a second duration based on a second length / size. In yet another embodiment, AP 1402 may select the larger of the first and second durations as time period 1524 (or time period 1526). This ensures that time period 1524 (or time period 1526) is long enough to accommodate the corresponding trigger frames of both APs 1404 and 1406. In yet another embodiment, AP 1402 may select the shorter of the first and second durations as time period 1524 (or time period 1526). This ensures that time period 1524 can be fully utilized by at least one of APs 1404 and 1406.

[0189] In another embodiment, time period 1524 (and / or time period 1526) may be based on a first length / size of the trigger frame indicated in frame 1504 and / or a first length / size of the trigger frame indicated in frame 1506. In an embodiment, AP1402 may determine a second length / size of the trigger frame based on the first length / size indicated in frame 1504 and / or the first length / size indicated in frame 1506. In an embodiment, time period 1524 (and / or time period 1526) may be based on the second length / size.

[0190] In an embodiment, MRTT frame 1508 may include the duration of time period 1524 (and / or time period 1526). In an embodiment, the start time of time period 1524 (and / or time period 1526) may be determined based on MRTT frame 1508. For example, the start time of time period 1524 may be 2 SIFS plus the CTS frame transmission time from the time MRTT frame 1508 is received. The end time of time period 1524 may be determined based on the start time and the indicated duration. The start time of time period 1526 may be based on the start time of time period 1524 (e.g., X microseconds from the start time of time period 1524). The end time of time period 1526 may be determined based on the start time of time period 1526 and the indicated duration of time period 1526.

[0191] In another embodiment, MRTT frame 1508 may include the start and end times of time period 1524 (and / or time period 1526), ​​the start time and duration of time period 1524 (and / or time period 1526), ​​or the duration and end time of time period 1524 (and / or time period 1526). In such embodiments, the start time of time period 1524 (and / or time period 1526) may not be based on MRTT frame 1508.

[0192] In another embodiment, the MRTT frame 1508 may indicate the time period 1524 (and / or the time period 1526) as a segment of the allocated time 1510. For example, the MRTT frame 1508 may indicate that the time period 1524 corresponds to the first half / third / quarter of the allocated time 1510, or the first X microseconds of the allocated time 1510, etc. For example, the MRTT frame 1508 may indicate that the time period 1526 corresponds to the last half / third / quarter of the allocated time 1510, or the last X microseconds of the allocated time 1510, etc.

[0193] In other embodiments, AP 1402 may initiate inter-AP TXS operation by transmitting frames other than MRTT frames. For example, AP 1402 may use multiple AP trigger frames to initiate inter-AP TXS operation. Multiple AP trigger frames may include / indicate the same information as described above included / indicated in MRTT frame 1508. APs 1404 and 1406 may or may not respond to, acknowledge or not acknowledge, the multiple AP trigger frames from AP 1402.

[0194] like Figure 15As shown, APs 1404 and 1406 can respond to MRTT frame 1508 by transmitting CTS frames 1512 and 1514 to AP 1402, respectively. Subsequently, for example, at SIFS after transmitting CTS frames 1512 and 1514, APs 1404 and 1406 can continue to communicate using allocated time 1510 according to the TXS mode indicated in MRTT frame 1508, taking into account time period 1524 (and / or time period 1526), ​​without triggering from AP 1402. In instance 1500, the TXS mode can allow APs 1404 and 1406 to communicate with AP 1402 or with another STA during allocated time 1510. Therefore, as Figure 15 As shown, AP 1404 can use the time period 1524 of the allocation time 1510 to send to the associated STA ( Figure 15 (Not shown in the diagram) Transmit (non-TB) DL PPDU 1516. DL PPDU 1516 may include a trigger frame, the length / size of which is determined by time period 1524 (and / or time period 1526). In this example, AP 1404 may use time period 1526 to transmit the trigger frame included in DL PPDU 1516. Similarly, as... Figure 15 As shown, AP 1406 can use the time period 1524 of the allocated time 1510 to send to the associated STA ( Figure 15 (Not shown in the image) Transmission (non-TB) DL PPDU 1518. DL PPDU 1518 may include a trigger frame whose length / size is determined by time period 1524 (and / or time period 1526). In the example, AP 1406 may use time period 1526 to transmit the trigger frame included in DL PPDU 1518.

[0195] In Example 1500, the combined length / size of one or more data frames and trigger frames to be transmitted by AP 1404 in DL PPDU 1516 can be greater than the combined length / size of one or more data frames and trigger frames to be transmitted by AP 1406 in DL PPDU 1518. In this example, AP 1402 can set time period 1524 based on the combined length / size of one or more data frames and trigger frames to be transmitted by AP 1404 in DL PPDU 1516. For example, AP 1404 can set a first time period 1524 equal to the combined length / size of one or more data frames and trigger frames to be transmitted by AP 1404 in DL PPDU 1516. Therefore, as Figure 15As shown, AP 1404 does not need to insert any padding bits in DL PPDU 1516 and can utilize the entire time period 1524 to transmit data / control information. Therefore, the utilization of allocation time 1510, and especially time period 1524, is increased. Since the combined length / size of one or more data frames and trigger frames to be transmitted by AP 1406 in DL PPDU 1518 is shorter than time period 1524, AP 1406 can insert padding bits into DL PPDU 1518. Padding bits can be inserted before or after the trigger frames included in DL PPDU 1518.

[0196] In this example, AP 1404 may use the remaining duration of allocation time 1510 to draw from one or more associated STAs, based on any indication in MRTT frame 1508. Figure 15 (Not shown in the image) Receives UL PPDU 1520. In this example, AP1406 may use the remaining duration of allocation time 1510 to receive data from one or more associated STAs, based on any indication in MRTT frame 1508. Figure 15 (Not shown) Receives UL PPDU 1522. In an embodiment, as described above, frame 1508 may further indicate a time period for UL PPDUs 1520 and 1522. In an embodiment, AP 1404 may signal the time period to one or more associated STAs scheduled to transmit UL PPDU 1520. In an embodiment, AP 1406 may signal the time period to one or more associated STAs scheduled to transmit UL PPDU 1522.

[0197] In this example, C-OFDMA can be used for the transmission of DL PPDU 1516 and 1518, and UL PPDU 1520 and 1522. Specifically, AP 1402 can allocate corresponding frequency resources orthogonal to each other to AP 1404 and 1406 within allocation time 1510. For example, AP 1402 can divide an 80 MHz channel into two non-overlapping 40 MHz channels, each allocated to one of the corresponding APs, AP 1404 and 1406. In this example, the frequency resources allocated to the AP are indicated in the RU allocation subfield of the user information field (which indicates the identifier of the AP) of MRTT frame 1508. Therefore, DL PPDU 1516 and UL PPDU 1520 can be transmitted on RUs orthogonal to the RUs used for the transmission of DL PPDU 1518 and UL PPDU 1522.

[0198] Figure 16Examples of A-Control fields 1602 and 1604 used in the embodiments are shown. A-Control fields 1602 and 1604 can be used to carry in QoS data frames / empty frames the number of STAs associated with the AP performing UL transmissions to the AP and / or the length / size of trigger frames included in DL transmissions from the AP. Figure 16 As shown, A-Control fields 1602 and 1604 may include a Control ID field indicating the type of A-Control fields 1602 and 1604. In an example, the Control ID field may indicate that A-Control fields 1602 and 1604 include a BSR for DL ​​coordination transmission (“C-BSR”). In an embodiment, A-Control field 1602 includes a “Number of UL STAs” field. The “Number of UL STAs” field indicates the number of STAs associated with the AP and performing UL transmissions to the AP as described above. In an embodiment, A-Control field 1604 includes a “Length of Trigger Frame” field. The “Length of Trigger Frame” field may include / indicate the length / size of the trigger frame included in the DL transmission from the AP as described above.

[0199] Figure 17 Example information elements 1702 and 1704 are shown for use in the embodiments. Information elements 1702 and 1704 can be used to carry in the action frame the number of STAs associated with the AP performing UL transmissions to the AP and / or the length / size of trigger frames included in DL transmissions from the AP. Figure 17 As shown, information elements 1702 and 1704 may include an element ID field, a length field, and an element ID extension field. The element ID field and the element ID extension field indicate the type of information elements 1702 and 1704. In an example, the element ID field and the element ID extension field may indicate that information elements 1702 and 1704 include a BSR for DL ​​Coordination Transmission (“C-BSR”). In an embodiment, information element 1702 further includes a “Number of UL STAs” field. The “Number of UL STAs” field indicates the number of STAs associated with the AP and performing UL transmissions to the AP as described above. In an embodiment, information element 1704 further includes a “Length of Trigger Frame” field. The “Length of Trigger Frame” field may include / indicate the length / size of the trigger frame included in the DL transmission from the AP as described above.

[0200] Figure 18 An example process 1800 according to an embodiment is shown. Example process 1800 can be executed by a first AP (e.g., AP 1402 described above). Figure 18 As shown, process 1800 includes steps 1802 and 1804.

[0201] Step 1802 includes the first AP receiving a first frame from the second AP indicating the number (zero or more) of STAs. In an example, the first AP and the second AP may form a multi-AP group. In an example, the first AP may be a shared AP (or master AP) in the multi-AP group, and the second AP may be a shared AP (or slave AP) in the multi-AP group. STAs may be associated with the second AP. The number of STAs indicated in the first frame may be the STAs that the second AP wishes to receive from it in a UL transmission. The number of STAs indicated in the first frame may be scheduled by the second AP for a UL transmission. The UL transmission may be part of a coordinated transmission. The coordinated transmission may include another UL transmission to the first AP or to a third AP. The coordinated transmission may be a C-OFDMA transmission. The coordinated transmission may be performed within the allocated time of the TXOP obtained by the first AP.

[0202] In one embodiment, the first frame may include an action frame. The action frame may include information elements, such as the number of STAs. In another embodiment, the first frame may include a QoS empty frame or a data frame. The QoS empty frame or data frame may include an A-Control field, which includes the number of STAs.

[0203] Step 1804 includes transmitting a second frame from the first AP to the second AP. This second frame indicates a time period for a DL PPDU, which includes a trigger frame for transmission from the second AP to STAs (the number of which is indicated in the first frame). In an embodiment, the time period is based on the number of STAs indicated in the first frame. In an embodiment, the time period corresponds to the transmission duration of the DL PPDU. In an embodiment, the trigger frame triggers the STA to perform a UL transmission. In an embodiment, the DL PPDU is transmitted for DL ​​transmission. The DL transmission may be part of a coordinated transmission that includes UL transmission.

[0204] In an embodiment, the second frame further indicates the allocation time of the TXOP obtained by the first AP. In an embodiment, the time period is within the allocation time of the TXOP. In an embodiment, the second frame includes an MRTT frame or a multi-AP trigger frame. In an embodiment, the second frame further indicates the identifier of the second AP.

[0205] In an embodiment, the first frame may include a BSR. The BSR may be a C-OFDMA BSR. In an embodiment, process 1800 may further include: transmitting a third frame requesting a BSR to the second AP; and receiving a first frame in response to the third frame. The third frame may include a Buffer Status Report Polling (BSRP) trigger frame, a basic trigger frame, a polling frame, or a request frame.

[0206] Figure 19Another example process 1900 according to an embodiment is shown. Example process 1900 can be executed by a first AP (e.g., AP 1402 described above). Figure 19 As shown, process 1900 includes steps 1902 and 1904.

[0207] Step 1902 includes receiving a first frame from the second AP by the first AP, the first frame indicating a first length of a trigger frame for transmission by the second AP in a DL PPDU for one or more STAs. In an example, the first AP and the second AP may form a multi-AP group. In an example, the first AP may be a shared AP (or master AP) in the multi-AP group, and the second AP may be a shared AP (or slave AP) in the multi-AP group. One or more STAs may be associated with the second AP. The one or more STAs may be STAs that the second AP wishes to receive from it in a UL transmission. In an embodiment, the trigger frame triggers the STAs to perform a UL transmission.

[0208] UL transmissions can be part of coordinated transmissions. Coordinated transmissions may include another UL transmission to a first AP or a third AP. Coordinated transmissions can be C-OFDMA transmissions. Coordinated transmissions can be performed within the allocated time of the TXOP obtained by the first AP. In an embodiment, a DL PPDU is transmitted for DL ​​transmissions. DL transmissions can be part of coordinated transmissions that include UL transmissions.

[0209] The first length indicated in the first frame may be preferred / recommended / selected by the second AP. The first length / size may be based on the total number of one or more STAs. In an embodiment, the first length is indicated in bytes.

[0210] Step 1904 includes: transmitting a second frame indicating the duration of the DL PPDU from the first AP to the second AP. In one embodiment, the duration of the DL PPDU is based on a first length of the trigger frame. In another embodiment, the duration is based on a second length of the trigger frame. The second length may be based on the first length. The second length may be determined by the first AP.

[0211] In an embodiment, the second frame may further indicate the allocation time of the TXOP obtained by the first AP. In an embodiment, the time period of the first portion is within the allocation time. In an embodiment, the second frame may further include the identifier of the second AP.

[0212] Figure 20 Another example process 2000 according to an embodiment is shown. Example process 200 can be executed by a first AP (e.g., AP 1404 or 1406 described above). Figure 20 As shown, process 2000 includes steps 2002 and 2004.

[0213] Step 2002 includes a first frame transmitting an indication of the number (zero or more) of STAs from the first AP to the second AP. In an example, the first AP and the second AP may form a multi-AP group. In an example, the second AP may be a shared AP (or master AP) in the multi-AP group, and the first AP may be a shared AP (or slave AP) in the multi-AP group. STAs may be associated with the first AP. The number of STAs indicated in the first frame may be the STAs that the first AP wishes to receive from it in a UL transmission. The number of STAs indicated in the first frame may be scheduled by the first AP for a UL transmission. The UL transmission may be part of a coordinated transmission. The coordinated transmission may include another UL transmission to the second AP or to a third AP. The coordinated transmission may be a C-OFDMA transmission. The coordinated transmission may be performed within the allocated time of the TXOP obtained by the second AP.

[0214] In one embodiment, the first frame may include an action frame. The action frame may include information elements, such as the number of STAs. In another embodiment, the first frame may include a QoS empty frame or a data frame. The QoS empty frame or data frame may include an A-Control field, which includes the number of STAs.

[0215] Step 2004 includes receiving a second frame from a second AP by a first AP. The second frame indicates a time period for a DL PPDU, the DL PPDU including a trigger frame for transmission by the first AP to STAs (the number of which is indicated in the first frame). In an embodiment, the time period is based on the number of STAs indicated in the first frame. In an embodiment, the time period corresponds to the transmission duration of the DL PPDU. In an embodiment, the trigger frame triggers the STA to perform a UL transmission. In an embodiment, the DL PPDU is transmitted for DL ​​transmission. The DL transmission may be part of a coordinated transmission that includes UL transmission.

[0216] In an embodiment, the second frame further indicates the allocation time of the TXOP obtained by the second AP. In an embodiment, the time period is within the allocation time of the TXOP. In an embodiment, the second frame includes an MRTT frame or a multi-AP trigger frame. In an embodiment, the second frame further indicates the identifier of the first AP.

[0217] In an embodiment, the first frame may include a BSR. The BSR may be a C-OFDMA BSR. In an embodiment, process 2000 may further include: receiving a third frame requesting a BSR from a second AP; and transmitting a first frame in response to the third frame. The third frame may include a Buffer Status Report Polling (BSRP) trigger frame, a basic trigger frame, a polling frame, or a request frame.

[0218] Figure 21Another example process 2100 according to an embodiment is shown. Example process 2100 can be executed by a first AP (e.g., AP 1404 or 1406 described above). Figure 21 As shown, process 2100 includes steps 2102 and 2204.

[0219] Step 2102 involves transmitting a first frame from the first AP to the second AP, the first frame indicating a first length of a trigger frame for transmission by the first AP in a DL PPDU for one or more STAs. In an example, the first AP and the second AP may form a multi-AP group. In an example, the second AP may be a shared AP (or master AP) in the multi-AP group, and the first AP may be a shared AP (or slave AP) in the multi-AP group. One or more STAs may be associated with the first AP. The one or more STAs may be STAs that the first AP wishes to receive from it in a UL transmission. In an embodiment, the trigger frame triggers the STAs to perform a UL transmission.

[0220] UL transmissions can be part of coordinated transmissions. Coordinated transmissions may include another UL transmission to a first AP or a third AP. Coordinated transmissions can be C-OFDMA transmissions. Coordinated transmissions can be performed within the allocated time of the TXOP obtained by the first AP. In an embodiment, a DL PPDU is transmitted for DL ​​transmissions. DL transmissions can be part of coordinated transmissions that include UL transmissions.

[0221] The first length indicated in the first frame may be preferred / recommended / selected by the second AP. The first length / size may be based on the total number of one or more STAs. In an embodiment, the first length is indicated in bytes.

[0222] Step 2104 includes: receiving a second frame from the second AP indicating the duration of the DL PPDU by the first AP. In one embodiment, the duration of the DL PPDU is based on a first length of the trigger frame. In another embodiment, the duration is based on a second length of the trigger frame. The second length may be based on the first length. The second length may be determined by the second AP.

[0223] In an embodiment, the second frame may further indicate the allocation time of the TXOP obtained by the second AP. In an embodiment, the time period of the first portion is within the allocation time. In an embodiment, the second frame may further include the identifier of the first AP.

Claims

1. A method comprising: The first access point (AP) receives a first frame from the second AP, the first frame indicating the number of stations (STAs) performing uplink UL transmissions to the second AP; as well as The first AP transmits a second frame to the second AP, and the second frame indicates: The allocation time of the transmission opportunity (TXOP) obtained by the first AP; The identifier of the second AP; as well as The allocated time period is the time period used for downlink physical layer protocol data units (DL PPDUs), the downlink physical layer protocol data units including trigger frames for the STAs, wherein the time period is based on the number of STAs.

2. A method comprising: The first access point (AP) receives a first frame from the second AP indicating the number of stations (STAs); as well as A second frame is transmitted from the first AP to the second AP. The second frame indicates a time period for a downlink physical layer protocol data unit (DLPPDU), which includes a trigger frame for transmission from the second AP to the STA.

3. The method of claim 2, wherein the second frame further indicates the allocation time of the transmission opportunity (TXOP) obtained by the first AP.

4. The method of claim 3, wherein the time period is the allocated time of the TXOP.

5. The method according to any one of claims 2 to 4, wherein the time period is based on the number of STAs.

6. The method of claim 5, wherein the time period corresponds to the transmission duration of the DL PPDU.

7. The method according to any one of claims 2 to 6, wherein the length of the trigger frame is based on the number of STAs.

8. The method according to any one of claims 2 to 7, wherein the first frame includes a buffer status report (BSR).

9. The method of claim 8, further comprising: The first AP transmits a third frame requesting the BSR to the second AP; as well as The first AP receives the first frame from the second AP as a response to the third frame.

10. The method of claim 9, wherein the third frame includes a Buffer Status Report Polling BSRP trigger frame, a basic trigger frame, a polling frame, or a request frame.

11. The method according to any one of claims 8 to 10, wherein the BSR comprises a coordinated orthogonal frequency division multiple access (C-OFDMA) BSR.

12. The method according to any one of claims 2 to 11, wherein the STA is associated with the second AP.

13. The method according to any one of claims 2 to 12, wherein the STA is scheduled by the second AP to perform uplink UL transmission to the second AP.

14. The method of claim 13, wherein the UL transmission occurs within the allocated time of the transmission opportunity TXOP obtained by the first AP.

15. The method according to any one of claims 13 to 14, wherein the trigger frame triggers the STA to perform the UL transmission.

16. The method according to any one of claims 13 to 15, wherein the UL transmission is part of a C-OFDMA UL transmission.

17. The method according to any one of claims 2 to 16, wherein the second frame includes a multi-user request to send a TXOP shared MU-RTS TXS trigger frame or a multi-AP trigger frame.

18. The method according to any one of claims 2 to 17, wherein the first frame includes an action frame.

19. The method of claim 18, wherein the action frame includes an information element, the information element including the number of STAs.

20. The method according to any one of claims 2 to 17, wherein the first frame comprises a Quality of Service (QoS) empty frame or a data frame.

21. The method of claim 20, wherein the QoS empty frame or data frame includes an aggregation control A-Control field, the aggregation control field including the number of STAs.

22. A method comprising: The first access point (AP) receives a first frame from the second AP, the first frame indicating a first length for a trigger frame for transmission by the second AP in a downlink physical layer protocol data unit (DL PPDU) for one or more station (STA) stations; as well as The first AP transmits a second frame to the second AP, and the second frame indicates: The allocation time of the transmission opportunity (TXOP) obtained by the first AP; The identifier of the second AP; and The duration of the DL PPDU within the allocated time.

23. The method of claim 22, wherein the first length is selected by the second AP.

24. The method according to any one of claims 22 to 23, wherein the first length is based on the number of the one or more STAs.

25. The method of any one of claims 22 to 24, wherein the duration of the DL PPDU is based on the first length of the trigger frame.

26. The method of claim 25, wherein the duration of the DL PPDU is based on a second length of the trigger frame.

27. The method of claim 26, wherein the second length of the trigger frame is based on the first length of the trigger frame.

28. The method of any one of claims 22 to 27, wherein the first length of the trigger frame is indicated in bytes.

29. A method comprising: A first frame is transmitted from the first access point (AP) to the second AP, and the first frame indicates the number of stations (STAs) that are making uplink UL transmissions to the first AP. as well as The first AP receives a second frame from the second AP, and the second frame indicates: The allocation time of the transmission opportunity (TXOP) obtained by the second AP; The identifier of the first AP; as well as The allocated time period is the time period used for downlink physical layer protocol data units (DL PPDUs), the downlink physical layer protocol data units including trigger frames for the STAs, wherein the time period is based on the number of STAs.

30. A method comprising: The first frame, indicating the number of STAs, is transmitted from the first access point (AP) to the second AP. as well as The first AP receives a second frame from the second AP. The second frame indicates a time period for a downlink physical layer protocol data unit (DL PPDU), which includes a trigger frame for the STA.

31. The method of claim 30, wherein the second frame further indicates the allocation time of a transmission opportunity (TXOP) obtained by the second AP.

32. The method of claim 31, wherein the time period is the allocated time of the TXOP.

33. The method according to any one of claims 30 to 32, wherein the time period is based on the number of STAs.

34. The method of claim 33, wherein the time period corresponds to the transmission duration of the DL PPDU.

35. The method according to any one of claims 30 to 34, wherein the length of the trigger frame is based on the number of STAs.

36. The method according to any one of claims 30 to 35, wherein the first frame includes a buffer status report (BSR).

37. The method of claim 36, further comprising: The first AP receives a third frame requesting the BSR from the second AP; as well as The first frame is transmitted from the first AP to the second AP as a response to the third frame.

38. The method of claim 37, wherein the third frame includes a Buffer Status Report Polling BSRP trigger frame, a basic trigger frame, a polling frame, or a request frame.

39. The method according to any one of claims 36 to 38, wherein the BSR comprises a coordinated orthogonal frequency division multiple access (C-OFDMA) BSR.

40. The method of any one of claims 30 to 39, wherein the STA is associated with the first AP.

41. The method according to any one of claims 30 to 40, wherein the STA is scheduled by the first AP to perform uplink UL transmission to the first AP.

42. The method of claim 41, wherein the UL transmission occurs within the allocated time of the transmission opportunity TXOP obtained by the second AP.

43. The method according to any one of claims 41 to 42, wherein the trigger frame triggers the STA to perform the UL transmission.

44. The method according to any one of claims 41 to 43, wherein the UL transmission is part of a C-OFDMA UL transmission.

45. The method of any one of claims 30 to 44, wherein the second frame comprises a multi-user request to send a TXOP shared MU-RTS TXS trigger frame or a multi-AP trigger frame.

46. ​​The method according to any one of claims 30 to 45, wherein the first frame includes an action frame.

47. The method of claim 46, wherein the action frame includes an information element, the information element including the number of STAs.

48. The method according to any one of claims 30 to 45, wherein the first frame comprises a Quality of Service (QoS) empty frame or a data frame.

49. The method of claim 48, wherein the QoS empty frame or data frame includes an aggregation control A-Control field, the aggregation control field including the number of STAs.

50. A method comprising: A first frame is transmitted from a first access point (AP) to a second AP. The first frame indicates a first length for a trigger frame for transmission by the first AP in a downlink physical layer protocol data unit (DL PPDU) for one or more station (STA) stations. as well as The first AP receives a second frame from the second AP, and the second frame indicates: The allocation time of the transmission opportunity (TXOP) obtained by the second AP; The identifier of the first AP; and The duration of the DL PPDU within the allocated time.

51. The method of claim 50, wherein the first length is selected by the first AP.

52. The method according to any one of claims 50 to 51, wherein the first length is based on the number of the one or more STAs.

53. The method of any one of claims 50 to 52, wherein the duration of the DL PPDU is based on the first length of the trigger frame.

54. The method of claim 53, wherein the duration of the DL PPDU is based on a second length of the trigger frame.

55. The method of claim 54, wherein the second length of the trigger frame is based on the first length of the trigger frame.

56. The method according to any one of claims 50 to 55, wherein the first length of the trigger frame is indicated in bytes.

57. An apparatus comprising: One or more processors; as well as A memory that stores instructions, which, when executed by the one or more processors, cause the device to perform the method according to any one of claims 1 to 56.

58. A non-transitory computer-readable medium comprising instructions that, when executed by one or more processors, cause the one or more processors to perform the method according to any one of claims 1 to 56.

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