Preamble duration coordination for multi-access point transmissions

Abstract

In one aspect, a first access point (AP) receives a first frame from a second AP, the first frame indicating a number of stations (STAs) associated with the second AP for downlink (DL) transmissions from the second AP. The AP transmits a second frame to the second AP, the second frame indicating: an allocated time of a transmission opportunity (TXOP) obtained by the first AP for the DL transmissions; an identifier of the second AP; and a time period for the DL transmissions by a preamble of a downlink (DL) physical layer protocol data unit (PPDU), the time period based on the number of STAs. In another aspect, a first AP transmits a frame to a second AP indicating a number of STAs associated with the first AP for DL transmissions. The first AP receives a frame indicating a time period of a portion of a DL PPDU, the time period based on the number of STAs.

Description

Cross-reference to related applications

[0001] This application claims priority to U.S. Provisional Application No. 63 / 541,319, filed September 29, 2023, the entire contents of which are incorporated herein 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 This is a block diagram showing 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 An example of a Quality of Service (QoS) empty frame indicating buffer status information is shown.

[0007] Figure 5 An example format of the Physical Layer (PHY) Protocol Data Unit (PPDU) is shown.

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

[0009] Figure 7 An example of a TXS program is shown (mode=1).

[0010] Figure 8 An example of a TXS program is shown (mode=2).

[0011] Figure 9 An example multi-AP network is shown.

[0012] Figure 10 This illustrates Coordinated Orthogonal Frequency Division Multiple Access (C-OFDMA).

[0013] Figure 11 This is an example showing the TXS procedure between APs.

[0014] Figure 12 An example PPDU that can be used for downlink (DL) physical layer protocol data unit (PPDU) or uplink (UL) PPDU is shown.

[0015] Figure 13 It is shown Figure 11 The image shows an example of a potential problem in the AP-to-AP TXS procedure.

[0016] Figure 14 An example of an AP-to-AP TXS procedure according to an embodiment is shown.

[0017] Figure 15 An example of an AP-to-TXS procedure according to another embodiment is shown.

[0018] Figure 16 An example aggregation control (A-Control) field that can be used in an embodiment is shown.

[0019] Figure 17 Example information elements that can be used in the embodiments are shown.

[0020] Figure 18 An example process according to an embodiment is shown.

[0021] Figure 19 Another example process according to an embodiment is shown.

[0022] Figure 20 Another example process according to an embodiment is shown.

[0023] Figure 21 Another example process according to an embodiment is shown. Detailed Implementation

[0024] 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 may 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 exemplary embodiments described. Embodiments of this disclosure will be described with reference to the accompanying drawings. Limitations, features, and / or elements from the disclosed exemplary embodiments may be combined to create further embodiments within the scope of this disclosure. Any figures 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, any actions listed in a flowchart may be reordered or optionally used only in certain embodiments.

[0025] 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, combinations thereof, etc. Example criteria may be based at least in part on, for example, wireless device or network node configuration, traffic load, initial system settings, packet size, traffic characteristics, combinations thereof, etc. Various example embodiments can be applied when one or more criteria are met. Therefore, example embodiments that selectively implement the disclosed protocols can be implemented.

[0026] In this disclosure, the terms “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.

[0027] If A and B are sets, and every element of A is also 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 example 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 example 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 example 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 example of one of a variety of suitable possibilities that may or may not be used in one or more of the various embodiments.

[0028] The term "configured" can refer to the capabilities of a device, whether the device is in an operational or non-operational state. "Configured" 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. Similarly, the term "control messages generated in the device" can mean that the control messages have parameters that can be used to configure specific characteristics in the device or to perform certain actions in the device, regardless of whether the device is in an operational or non-operational state.

[0029] 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 an example embodiment, when one or more messages / frames include multiple parameters, this means that a parameter among 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.

[0030] 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 different 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.

[0031] Many 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 defined interfaces to other elements. Modules described in this disclosure can be implemented as 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 result of functional modules.

[0032] Figure 1 An example wireless communication network in which embodiments of the present disclosure may be implemented is shown.

[0033] 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.

[0034] 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.

[0035] DS 130 can be configured to connect BSS 110-1 and BSS 110-2. Therefore, DS 130 can enable Extended Service Set (ESS) 150. Within ESS 150, APs 104-1 and 104-2 are connected via DS 130 and can have the same Service Set Identifier (SSID).

[0036] 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.

[0037] Figure 1 The example wireless communication network shown may also include 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 through an AP).

[0038] 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.

[0039] 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" may 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.

[0040] 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 part (or "traditional preamble") and a non-traditional part (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 part of the preamble are based on the specific IEEE 802.11 protocol to be used for transmitting the payload.

[0041] 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, multiple 20 MHz channels can be bonded together to transmit PPDUs through physical channels with bandwidths of 40 MHz, 80 MHz, 160 MHz, or 320 MHz.

[0042] Figure 2 This is a block diagram illustrating example implementations of the STA 210 and AP 260. (As shown...) 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.

[0043] 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.

[0044] 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.

[0045] 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. One or more of transceivers 240 / 290 can be used to implement multiple PHY layers.

[0046] The Target Wake-Up Time (TWT) 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. TWTs can reduce the amount of time a STA utilizing power management modes might require to wake up. TWTs can be standalone or broadcast. Standalone TWTs follow a negotiated TWT protocol between STAs. Broadcast TWTs are based on schedule settings and are provided to STAs by the AP.

[0047] In a standalone 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 assigned 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 a TWT protocol is established between the two, the TWT responding STA can transmit the TWT value to the TWT requesting STA.

[0048] When using explicit TWT, the TWT requesting STA can wake 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.

[0049] 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 a TWT SP series can indicate the start time of the first TWT SP in the series. The start time of a subsequent TWT SP can be determined by adding the value of the TWT wake-up interval to the start time of the current TWT SP. In the example, a TWT request STA woken up for an implicit TWT SP can go into a dormant 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).

[0050] 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.

[0051] 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 verify the received MAC frames using the Frame Check Sequence (FCS) contained in the frames and can interpret certain fields based on the MAC headers of all frames.

[0052] like Figure 3 As shown, a MAC frame includes a MAC header, a variable-length frame body, and a frame check sequence (FCS).

[0053] The MAC header includes 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.

[0054] 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.

[0055] 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.

[0056] The Type and Subtype subfields together identify the function of a MAC frame. There are three frame types: control, data, and management. Each frame type 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.

[0057] The `to` subfield indicates whether the data frame is directed to a distribution system (DS). The `from` subfield indicates whether the data frame originated from a DS.

[0058] 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 in a 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.

[0059] 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.

[0060] The power management subfield is used to indicate the power management mode of the STA.

[0061] 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.

[0062] If the frame body field contains information that has been processed by an encryption encapsulation algorithm, then the protected frame subfield is set to 1.

[0063] The +HTC subfield indicates that the MAC frame contains the HT control field.

[0064] The Duration / ID field in the MAC header indicates different content 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 indicating to the STA the amount of time it must delay access to the shared medium.

[0065] A MAC frame format can have 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. The use of certain 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 the intended receiver of the frame, and address 2 (if present) always identifies the sender of the frame.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] The frame body field is a variable-length field that contains information specific to each frame type and subtype. It can contain one or more MSDUs or MMPDUs. The minimum length of the frame body is 0 octets.

[0070] 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 frame body.

[0071] Figure 4Example 400 of a Quality of Service (QoS) empty frame indicating buffer status information is shown. 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. A QoS empty frame indicating buffer status information can be transmitted from a STA to an AP.

[0072] 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).

[0073] The TID subfield identifies the TC or TS that is 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., values ​​0 to 7 are allowed for Enhanced Distributed Channel Access (EDCA) access policies to identify the user priority of the TC or TS).

[0074] The ack policy indicator subfield and other information identify the acknowledgment policy to be followed after the MPDU is delivered (e.g., normal ack, implicit block ack request, no ack, block ack, etc.). The queue size subfield is an 8-bit field that indicates the amount of buffered traffic at the STA used to transmit to the AP identified by the receive address of the frame containing this subfield for a given TC or TS. The queue size subfield is present in the 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 duration of the TXOP assigned to the STA or to determine the uplink (UL) resources assigned to the STA.

[0075] In frames sent to or from inefficient (non-HE) STAs, the following rules may be applied 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 can 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 receives data containing scaling factors SF and unscaled values UV Get queue size from QoS control field 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 instead of the queue size subfield, indicates to the sending STA the duration, in 32 microseconds (µs), required for the next TXOP for the specified TID. The requested TXOP duration subfield is set to 0 to indicate that no TXOP is requested for the specified TID in the current service period (SP). The requested TXOP duration subfield is set to a non-zero value to indicate 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 Class Index (ACI) bitmap subfield of the HT control field, the incremental TID subfield, the ACI high subfield, the scaling factor subfield, the queue size high subfield, and the queue size full subfield.

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

[0086] The values ​​of the ΔTID subfield and the ACI bitmap subfield indicate the number of TIDs that the STA is reporting in the buffer state.

[0087] The ACI high subfield indicates the ACI of the AC indicated by 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 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 for the AC identified by the ACI high subfield. SF The octet is 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 for all Acs identified by the ACI bitmap subfield. SFThe octet is intended for use by the STA identified by the receive address of the frame containing the BSR control subfield.

[0091] The queue size values ​​in the queue size high and queue size full subfields are the total size of all MSDUs and A-MSDUs buffered at the STA in the delivery queues for MSDUs and A-MSDUs associated with the AC, as specified in the ACI high and ACI bitmap subfields respectively, rounded up. SF The closest multiple of an octet.

[0092] The queue size value of 254 in both the queue size high and queue size full subfields 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 An example format for a PPDU is shown. As shown in the figure, a PPDU can contain a PHY preamble, a PHY header, a PSDU, and a tail and padding bits.

[0095] A PSDU can 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 can contain an MSDU or an A-MSDU.

[0096] By default, MSDU transfer is performed 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 based on each MSDU.

[0097] The STA can differentiate MSDU delivery based on the specified Traffic Category (TC) or Traffic Flow (TS) of each MSDU. 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 class with that UP. The UP can be provided directly in the UP parameter 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 (unrequested BSR) in the QoS control field or BSR control subfield of any frame transmitted to the AP, or explicitly (requested BSR) in a frame sent to the AP in response to a BSRP trigger frame.

[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 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 receiving the BSR control subfield, then 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 Transmit (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. The MU-RTS trigger frame where the Triggered TXOP Sharing Mode subfield is set to a non-zero value is called a MU-RTS TXS Trigger (MRTT) frame.

[0107] In the 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 the 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 the STA. In the example, a direct wireless link is established according to the Channel Direct Link Establishment (TDLS) protocol.

[0108] Figure 6 An exemplary MRTT frame 600 that can be used in a TXS procedure is shown. Figure 6 As shown, the example MRTT frame 600 may include a frame control field, a duration field, a receiver address (RA) field, a transmitter address (TA) field, a common information field, a user information list field, a padding field, and / or a frame check sequence (FCS) field.

[0109] In the 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 6 As 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 shared 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 can contain a trigger TXOP shared mode subfield. In the example, the trigger TXOP shared mode subfield can be set to a non-zero value (e.g., 1 or 2). In the example, 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 another example, 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 the example, the 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 the 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 can indicate 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 Example 700 of the TXS program (mode=1) is shown. Figure 7As 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 can include data frames, control frames, management frames, or action frames.

[0117] In the example, MRTT frame 720 may include a Trigger TXOP Shared Mode subfield, which indicates a TXS mode and / or subfield, which indicates a first time period corresponding to the allocated time. In the 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 the 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 Example 800 of the TXS program (mode=2) is shown. 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 can include data frames, control frames, management frames, or action frames.

[0120] In the example, MRTT frame 820 may include a Trigger TXOP Shared Mode subfield, which indicates a TXS mode and / or subfield, which indicates a first time period corresponding to the allocated time. In the 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 720. In the 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 An example multi-AP network 900 is shown. The example multi-AP network 900 can be a multi-AP network according to the Wi-Fi Alliance standard specifications 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 configure APs on 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 involve 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 can use different transmission techniques, such as coordinated OFDMA, coordinated spatial reuse, 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 master AP in the multi-AP group. In one approach, the AP controller and / or the master AP can control time and / or frequency sharing in a TXOP. For example, when one AP in the multi-AP group (e.g., the master AP) acquires a TXOP, the AP controller and / or the master 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 master AP in the multi-AP group. The master 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 assigning 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 (e.g., PPDU format, guard interval, symbol duration, etc.) for the multi-AP transmission. During the transmission period, multiple APs simultaneously access the assigned 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 communicating during the allocated time.

[0131] Figure 11 This is example 1100 illustrating the TXS procedure between APs. For example... Figure 11 As shown, Example 1100 includes APs 1102, 1104, 1106, and 1108. In this example, APs 1102, 1104, 1106, and 1108 can form the above-described... Figure 9 The document describes a multi-AP group. 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 communicate with AP 1102 only during allocation time 1132 (e.g., when 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 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 example 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 Transmit (non-TB) downlink (DL) PPDU 1114 from the associated STA (not shown) Figure 11 (Not shown in the image) Receive uplink (UL) PPDU 1116.

[0134] In the 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 the 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 communicate with AP 1102 only 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 Example 1100, the TXS mode can allow 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 Transmit (non-TB) DLPPDU 1126 from the associated STA (not shown in the image) and from the associated STA ( Figure 11 (Not shown in the image) Receives UL PPDU 1130.

[0136] In the example, C-OFDMA can be used for the transmission of DL PPDUs 1124 and 1126, and UL PPDUs 1128 and 1130. Specifically, AP 1102 can assign corresponding frequency resources that are orthogonal to each other to APs 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 assigned to one of the corresponding APs, AP 1106 and 1108. In the example, the frequency resources assigned 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 transmitting DL PPDU 1126 and UL PPDU 1130.

[0137] Figure 12 An example PPDU 1200 is shown that can be used for downlink DL PPDU or UL PPDU. For example, the 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 PPDU1200 includes a non-high throughput (non-HT) short training field (L-STF), a non-HT long training field (L-LTF), a non-HT signal field (L-SIG), a non-HT repeated 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] L-STF is used by the receiver of the PPDU 1200 to synchronize with the carrier frequency and frame timing of the transmitter of the PPDU 1200, and to adjust the receiver signal gain.

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

[0141] L-SIG and RL-SIG contain the parameters needed to demodulate the data field. The L-SIG can be equalized using the channel coefficients estimated with L-LTF, and then 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 the position of 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] The receiver of the PPDU 1200 uses UHR-STF and one or more UHR-LTF to estimate the channel coefficients in order to equalize the channel response (e.g., amplitude and phase distortion) in the data field of the 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 Example 1300 shows Figure 11 The diagram illustrates potential problems in the AP-to-AP 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 communicate with AP1102 only 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 Example 1300, the TXS mode can allow 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) receives UL PPDU 1306. Similarly, AP1108 can use allocation time 1134 to send to the associated STA ( Figure 13 (Not shown in the image) Transmits DL PPDU 1304 and from the associated STA ( Figure 13 (Not shown in the image) Receives UL PPDU 1308.

[0150] In the example, C-OFDMA can be used for the transmission of DL PPDUs 1302 and 1304, and UL PPDUs 1306 and 1308. Specifically, AP 1102 can assign corresponding frequency resources that are orthogonal to each other to APs 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 assigned to one of the corresponding APs, AP 1106 and 1108. In the example, the frequency resources assigned 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 1302 and UL PPDU 1306 can be transmitted on RUs orthogonal to the RUs used for transmitting 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] However, in some implementations, the indication of the first time period and / or the second time period by AP 1102 may be insufficient to achieve OFDM symbol alignment between DL PPDUs 1302 and 1304 and / or UL PPDUs 1306 and 1308. For example, in an implementation, each of DL PPDUs 1302 and 1304 may consist of a first portion and a second portion. The first portion may include a first set of fields of the DL PPDU, and the second portion may include a second set of fields of the DL PPDU. In an implementation, one or more of the first set of fields of the first portion may contain information about one or more second fields of the second portion. Thus, the length of the first portion may affect the length of the second portion, and vice versa. In an implementation, the first portion and the second portion may use different OFDM symbol durations. Therefore, alignment of DL PPDUs 1302 and 1304 may further require time alignment of the first portions of DL PPDUs 1302 and 1304 as well as time alignment of the second portions of DL PPDUs 1302 and 1304. This also applies to UL PPDU 1306 and 1308, making the alignment of UL PPDU 1306 and 1308 potentially require further time alignment of the first part of UL PPDU 1306 and 1308 as well as the time alignment of the second part of UL PPDU 1306 and 1308.

[0153] In this implementation, in addition to the first time period used for DL ​​transmission, AP 1102 may also indicate a third time period (within the first time period) for the first portion of DL transmission. The third time period can be used for the transmission of the first portion of DL PPDUs 1302 and 1304. In this implementation, in addition to the second time period for UL transmission, AP 1102 may also indicate a fourth time period (within the second time period) for the second portion of UL transmission. The fourth time period can be used for the transmission of the second portion of UL PPDUs 1306 and 1308.

[0154] However, without understanding the characteristics of the downlink data that each of AP1106 and 1108 intends to transmit during DL transmission, the third time period set by AP 1102 may be suboptimal and could lead to wasted DL resources. For example, as Figure 13As shown, AP 1102 can be configured with a third time period for DL ​​transmission in a manner that substantially exceeds the DL transmission requirements of AP 1106 and / or 1108. Therefore, both AP 1106 and 1108 may need to be padded to align the first portions of DLPPDU 1302 and 1304 and the second portions of DLPPDU 1302 and 1304. In another example, the third time period may be set too short to meet the DL transmission requirements of AP 1106 and / or 1108. Since the length of the first portion (transmitted during the third time period) can affect the length of the second portion (transmitted during the fourth time period), a third time period that is too short and limits the length of the first portion of DLPPDU 1302 and 1304 may also limit the length of the second portion of DLPPDU 1302 and 1304. This could result in the fourth time period being too long for the second portion of DL PPDUs 1302 and 1304, and APs 1106 and 1108 might have to pad for the second portion of DL PPDUs 1302 and 1304 to ensure time alignment. The same problem could also occur with UL PPDUs 1306 and 1308. That is, without knowing the characteristics of the uplink data that each of APs 1106 and 1108 intends to receive during UL transmission, the way AP 1102 can be configured for the fourth time period for UL transmission might be suboptimal and could lead to a waste of UL resources.

[0155] 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 associated with the first AP for DL ​​transmissions from the second AP. The number of STAs indicated in the first frame may be STAs that the first AP intends or wishes to transmit to it in a DL transmission. The first AP may be a shared AP, and the second AP may be a shared AP. The DL transmission may be part of a multi-AP transmission coordinated / initiated by the second AP. The multi-AP transmission may be performed within the allocated time of a TXOP obtained by the second AP. The second AP may send a second frame to the first AP, the second frame indicating the time period for a first portion of a DLPPDU to be transmitted via DL. In an embodiment, the time period for the first portion of the DL PPDU is based on the number of STAs indicated in the first frame. In another aspect, the first AP may send a first frame to the second AP, the first frame indicating the duration for a first portion of a DL PPDU to be transmitted from the first AP to one or more STAs associated with the first AP via DL. The first AP may receive a second frame from the second AP, the second frame indicating the time period for the first portion of the DL PPDU. In an embodiment, the time period is based on the duration indicated in the first frame. Further aspects and details of the embodiments are presented in the exemplary embodiments described below.

[0156] Figure 14 Example 1400 of an inter-AP TXS procedure according to an embodiment is shown. Figure 14 As shown, Example 1400 includes APs 1402, 1404, and 1406. In this example, APs 1402, 1404, and 1406 can form the above-described... Figure 9 The multi-AP group described herein. In the 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).

[0157] like Figure 14As shown, Example 1400 may begin with AP 1404 transmitting frame 1408 to AP 1402. In an embodiment, frame 1408 may indicate the number of STAs associated with AP 1404 for a DL transmission from AP 1404. The number of STAs indicated in frame 1408 may be STAs that AP 1404 intends or wishes to send to in the DL transmission. The DL transmission from AP 1404 may be part of a multi-AP transmission. The multi-AP transmission may be performed within the allocated time of the TXOP obtained by AP 1402. The multi-AP transmission may be performed in the context of the inter-AP TXS procedure as described above. The multi-AP transmission may or may not include AP 1402. The multi-AP transmission may be a coordinated DL PPDU transmission performed by AP 1402 and one or more of APs 1404 and 1406. Alternatively, as Figure 14 As shown, multi-AP transmission can be coordinated DLPPDU transmission performed by APs 1404 and 1406. Coordinated DLPPDU transmission can include C-OFDMA transmission, coordinated spatial reuse (C-SR) transmission, coordinated beamforming (C-BF) transmission, or coordinated joint transmission.

[0158] In an embodiment, frame 1408 further indicates DL transmission parameters for the transmission of the first part of the DL transmission in the DL PPDU. In an embodiment, the DL transmission parameters may include / indicate one or more of the following for the transmission of the first part: MCS, bandwidth (BW) size, RU size, PPDU type, or number of spatial streams (Nss).

[0159] In embodiments where DL transmission parameters include / indicate MCS, frame 1408 may include an MCS index. In another embodiment, in addition to the MCS index, frame 1408 may also indicate the PPDU type / format (e.g., HT, HE, VHT, EHT, UHR, etc.). In yet another embodiment, frame 1408 may further indicate the requested bandwidth for DL ​​transmission (e.g., 20 MHz, 40 MHz, etc.). In embodiments, frame 1408 may indicate multiple MCS indices for multiple bandwidth values ​​for DL ​​transmission.

[0160] In this embodiment, the DL transmission parameters can be determined by AP 1404. The DL transmission parameters can be selected by AP 1404 from a plurality of DL transmission parameters. These plurality of DL transmission parameters can be pre-configured in AP 1404. In this example, the DL transmission parameters can be suggested by AP 1404 for DL ​​transmission. For example, the DL transmission parameters can be preferred parameters for DL ​​transmission.

[0161] In another embodiment, frame 1408 may indicate the duration of the first part of the DL PPDU being transmitted from AP 1404 via DL.

[0162] In another embodiment, frame 1408 may indicate the duration of DL transmission from AP 1404 for a first field within the first portion of the DL PPDU. For example, frame 1408 may indicate the duration of the UHR-SIG field within the first portion of the DL PPDU. The UHR-SIG field may be the first field within the first portion of the DL PPDU.

[0163] 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 frame / empty frame, the QoS data frame / empty frame may include an aggregation control (A-Control) field, which includes, for example... Figure 16 The number of STAs and / or the duration of the first portion of the DL PPDU (and / or the duration of the fields in the first portion of the DL PPDU) shown. When frame 1408 is an action frame, the action frame may include information elements (or information fields) that include the number of STAs and / or the duration of the first portion of the DL PPDU (and / or the duration of the fields in the first portion of the DL PPDU). For example, the information element in Figure 17 As shown in the image.

[0164] In an embodiment, frame 1408 may also include a DL buffer status report (BSR). The DL BSR may indicate the amount of traffic buffered for DL ​​transmissions at AP 1404. The DL BSR may indicate as referenced above. Figure 4 The described amount of buffered traffic (e.g., in the queue size subfield). In one implementation, buffered traffic may correspond to all traffic buffered for DL ​​transmissions at AP 1404. In another implementation, buffered traffic may correspond to traffic buffered for DL ​​transmissions to one or more STAs whose quantity is indicated in frame 1408. Alternatively or additionally, buffered traffic may correspond to traffic buffered for DL ​​transmissions for a specific Access Class (AC) or TID.

[0165] In the example, example 1400 may also include AP 1406 transmitting frame 1410 to AP 1402. Frame 1410 may be transmitted before or after frame 1408. In an embodiment, frame 1410 may indicate the number of STAs associated with AP 1406 for DL ​​transmissions from AP 1406. DL transmissions from AP 1406 may be part of a multi-AP transmission that includes DL transmissions from AP 1404. Frame 1410 is similar to frame 1408. The same description above regarding frame 1408 applies to frame 1410.

[0166] Subsequently, AP 1402 can acquire a TXOP and initiate an inter-AP TXS operation by transmitting MRTT frame 1412 to APs 1404 and 1406. MRTT frame 1412 can have a format similar to the MU-RTS trigger frame 600 described above. In the example, MRTT frame 1412 can 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) and the allocation time 1414 of the TXOP (e.g., in the corresponding allocation duration subfield of the user information field). Additionally, MRTT frame 1412 can indicate the TXS mode (e.g., in the trigger TXOP sharing mode subfield of the common information field of MRTT frame 1412). 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.

[0167] In an embodiment, MRTT frame 1412 may further indicate a time period 1428 within allocation time 1414 for multi-AP transmission. Multi-AP transmission may or may not include AP 1402. Multi-AP transmission may be a coordinated DL PPDU transmission performed by AP 1402 and one or more of APs 1404 and 1406. Alternatively, as Figure 14 As shown, multi-AP transmission can be a coordinated DL PPDU transmission performed by APs 1404 and 1406. Coordinated DL PPDU transmission can include C-OFDMA transmission, coordinated spatial reuse (C-SR) transmission, coordinated beamforming (C-BF) transmission, or coordinated joint transmission. In an embodiment, multi-AP transmission can be a response to frames 1408 and 1410 from APs 1404 and 1406, respectively, which signal information about the corresponding DL transmissions from APs 1404 and 1406.

[0168] In one embodiment, MRTT frame 1412 may further indicate a time period 1430 during which the first portion of the DL PPDU is transmitted from AP 1404 and / or from AP 1406. In another 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. In this embodiment, time period 1430 corresponds to the transmission duration of the first portion of the DL PPDU. In yet another embodiment, time period 1430 may also be based on the DL transmission parameters indicated in frame 1408 and / or frame 1410.

[0169] In the example, a DL PPDU can have the following characteristics: Figure 12 The format shown is described. In an embodiment, the first part may include one or more of the following: L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and UHR-SIG of the DL PPDU. In an example, the first part includes L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and UHR-SIG of the DL PPDU. In another embodiment, the first part may include one or more of the following: L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, UHR-SIG, UHR-STF, and UHR-LTF of the DL PPDU. In an example, the first part includes L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, UHR-SIG, UHR-STF, and UHR-LTF of the DL PPDU.

[0170] In one embodiment, AP 1402 may determine a first length of the first portion of the DL PPDU based on the number of STAs indicated in frame 1408. In another embodiment, AP 1402 may determine a second length of the first portion of the DL PPDU based on the number of STAs indicated in frame 1410. In one example, based on the number of STAs indicated in frames 1408 / 1410, AP 1402 may determine the desired size (e.g., the number of OFDM symbols) of one or more fields of the first portion, which varies with the number of STAs served by the DL PPDU. For example, the UHR-SIG field may include common fields and user-specific fields. The user-specific fields may include N user fields (N = 1, 2, 3, …) based on the number of STAs served by the DL PPDU. In another example, AP 1402 may determine the required number / size of UHR-LTFs for the DL PPDU.

[0171] In one embodiment, AP 1402 may determine a first duration based on a first length of a first portion of the DL PPDU. In another embodiment, AP 1402 may determine a second duration based on a second length of the first portion of the DL PPDU. In yet another embodiment, AP 1402 may select the larger of the first and second durations as the time period 1430. This ensures that time period 1430 is long enough to accommodate the DL traffic requirements of both APs 1404 and 1406. In another embodiment, time period 1430 may be limited by the maximum duration of the first portion of the PPDU. That is, time period 1430 cannot exceed the maximum duration. In yet another embodiment, AP 1402 may select the shorter of the first and second durations as time period 1430. This ensures that at least one of APs 1404 and 1406 can fully utilize time period 1430.

[0172] In an embodiment, MRTT frame 1412 may include the duration of time period 1430. In an embodiment, the start time of time period 1430 may be determined based on MRTT frame 1412. For example, the start time of time period 1430 may be the time elapsed after two SIFS plus CTS frame transmission times, starting from the time MRTT frame 1412 is received. The end time of time period 1430 may be determined based on the start time and the indicated duration.

[0173] In another embodiment, MRTT frame 1412 may include the start and end times of time period 1430, the start and duration of time period 1430, or the duration and end time of time period 1430. In this embodiment, the start time of time period 1430 may not be based on MRTT frame 1412.

[0174] In another embodiment, the MRTT frame 1412 may indicate the time period 1430 as a segment of the allocated time 1414. For example, the MRTT frame 1412 may indicate that the time period 1430 corresponds to the first half / first third / first quarter of the allocated time 1414, or the first X microseconds of the allocated time 1414, etc.

[0175] In another embodiment, the MRTT frame 1412 may indicate the time period 1430 by indicating the number of OFDM symbols to be transmitted during the time period 1430 (based on a given duration (e.g., 4 microseconds) of the OFDM symbols in the first part).

[0176] In other embodiments, AP 1402 may initiate inter-AP TXS operation by transmitting frames other than MRTT frames. For example, AP 1402 may use a multi-AP trigger frame to initiate inter-AP TXS operation. The multi-AP trigger frame may include / indicate the same information as described above included / indicated in MRTT frame 1412. APs 1404 and 1406 may respond to or acknowledge the multi-AP trigger frame from AP 1402, or may not respond to or acknowledge it.

[0177] 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 communicating using allocated time 1414 according to the TXS mode indicated in MRTT frame 1412 and taking into account time period 1428, without triggering from AP 1402. In example 1400, the TXS mode can allow 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. When transmitting DL PPDU 1420, AP 1404 can use time period 1430 for the first part of DL PPDU 1420. AP 1404 can insert padding bits at the end of the first part to ensure that the transmission duration of the first part is equal to time period 1430. Padding bits can be inserted in the middle of the first part. For example, padding bits can be added at the end of the UHR-SIG field of the first part, or within the UHR-SIG field, or just before the CRC field of the UHR-SIG field. Similarly, AP 1406 can use time period 1428 to transmit to the associated STA ( Figure 14 (Not shown in the diagram) Transmit (non-TB) DL PPDU 1422. When transmitting DL PPDU 1422, AP 1404 can use time period 1430 for the first part of DL PPDU 1422. With time period 1430 set by AP 1402 as described above, AP 1406 may not need to insert any padding bits at the end of the first part of DL PPDU 1422, and can use the entire time period 1430 for the transmission of the first part of DL PPDU 1422. Therefore, the utilization of time allocation 1414, especially the utilization of time period 1430, is improved.

[0178] In the example, AP 1404 can use the remaining duration of allocation time 1414 from the associated STA based on any indication in MRTT frame 1412. Figure 14 (Not shown in the image) receives UL PPDU 1424. In the example, AP 1406 can use the remaining duration of allocation time 1414 from the associated STA (not shown in the image) according to 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 of the first portion of UL PPDUs 1424 and 1426. In an embodiment, AP 1404 may signal the time period to its associated STA that is scheduled to transmit UL PPDU 1424. In an embodiment, AP 1406 may signal the time period to its associated STA that is scheduled to transmit UL PPDU 1426.

[0179] In the 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 assign corresponding frequency resources that are 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 assigned to one of the corresponding APs, AP 1404 and 1406. In the example, the frequency resources assigned 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 transmitting DL PPDU 1422 and UL PPDU 1426.

[0180] Figure 15 Example 1500 of an inter-AP TXS procedure according to another embodiment is shown. Figure 15 As shown, Example 1500 also includes the references above. Figure 14 The described APs are 1402, 1404, and 1406. In the examples, APs 1402, 1404, and 1406 can form the above-described... Figure 9 The multi-AP group described herein. In the 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).

[0181] like Figure 15 As shown, Example 1500 may begin with AP 1402 transmitting frame 1502 to AP 1404 and / or AP 1406. In an embodiment, frame 1502 requests a DL BSR from AP 1404 and / or AP 1406 for use in a multi-AP transmission. The multi-AP transmission may be performed within the allocated time of the TXOP obtained by AP 1402. The multi-AP transmission may be performed within the context of the inter-AP TXS procedure as described above. The multi-AP transmission may or may not include AP 1402. The multi-AP transmission may be a coordinated DL PPDU transmission performed by AP 1402 and one or more of APs 1404 and 1406. Alternatively, as Figure 15 As shown, multi-AP transmission can be a coordinated DL PPDU transmission performed by APs 1404 and 1406. Coordinated DL PPDU transmission can include C-OFDMA transmission, coordinated spatial reuse (C-SR) transmission, coordinated beamforming (C-BF) transmission, or coordinated joint transmission. Frame 1502 can include a Buffer Status Report Polling (BSRP) triggered frame, a basic triggered frame, a polling frame, or a request frame.

[0182] In one embodiment, AP 1404 can respond to frame 1502 by transmitting frame 1504 to AP 1402. In this embodiment, frame 1504 includes a DL BSR for multi-AP transmission. The DL BSR can indicate the amount of traffic buffered at AP 1404 for DL ​​transmission. The DL BSR can indicate as referenced above. Figure 4 The described amount of buffered traffic (e.g., in the queue size subfield). In one implementation, buffered traffic may correspond to all traffic buffered at AP 1404 for DL ​​transmission. In another implementation, buffered traffic may correspond to traffic buffered for DL ​​transmission to a specific STA that AP 1404 intends to serve during multi-AP transmission. Alternatively or additionally, buffered traffic may correspond to traffic buffered for DL ​​transmission for a specific Access Class (AC) or TID.

[0183] In an embodiment, frame 1504 may additionally or alternatively indicate the number of STAs associated with AP 1404 for DL ​​transmissions from AP 1404. The number of STAs indicated in frame 1504 may be STAs that AP 1404 intends or wishes to send to in DL transmissions. DL transmissions from AP 1404 may be part of a multi-AP transmission.

[0184] In an embodiment, frame 1504 further indicates DL transmission parameters for the transmission of the first part of the DL transmission in the DL PPDU. In an embodiment, the DL transmission parameters may include / indicate one or more of the following for the transmission of the first part: MCS, bandwidth (BW) size, RU size, PPDU type, or number of spatial streams (Nss).

[0185] In embodiments where DL transmission parameters include / indicate MCS, frame 1504 may include an MCS index. In another embodiment, in addition to the MCS index, frame 1504 may also indicate the PPDU type / format (e.g., HT, HE, VHT, EHT, UHR, etc.). In yet another embodiment, frame 1504 may further indicate the requested bandwidth for DL ​​transmission (e.g., 20 MHz, 40 MHz, etc.). In embodiments, frame 1504 may indicate multiple MCS indices for multiple bandwidth values ​​for DL ​​transmission.

[0186] In this embodiment, the DL transmission parameters can be determined by AP 1404. The DL transmission parameters can be selected by AP 1404 from a plurality of DL transmission parameters. These plurality of DL transmission parameters can be pre-configured in AP 1404. In this example, the DL transmission parameters can be suggested by AP 1404 for DL ​​transmission. For example, the DL transmission parameters can be preferred parameters for DL ​​transmission.

[0187] In another embodiment, frame 1504 may indicate the duration of the first part of the DL PPDU being transmitted from AP 1404 via DL.

[0188] In another embodiment, frame 1408 may indicate the duration of DL transmission from AP 1404 for a first field within the first portion of the DL PPDU. For example, frame 1408 may indicate the duration of the UHR-SIG field within the first portion of the DL PPDU. The UHR-SIG field may be the first field within the first portion of the DL PPDU.

[0189] In an embodiment, for example, frame 1504 may be a QoS data frame / empty frame or an action frame. When frame 1504 is a QoS data frame / empty frame, the QoS data frame / empty frame may include an aggregation control (A-Control) field, which includes, for example... Figure 16 The number of STAs and / or the duration of the first portion of the DL PPDU (and / or the duration of the fields in the first portion of the DL PPDU) shown. When frame 1504 is an action frame, the action frame may include information elements (or information fields) that include the number of STAs and / or the duration of the first portion of the DL PPDU (and / or the duration of the fields in the first portion of the DL PPDU). For example, the information element in Figure 17 As shown in the image.

[0190] In the 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 an embodiment, frame 1506 may indicate the number of STAs associated with AP 1406 for DL ​​transmissions from AP 1406. DL transmissions from AP 1406 may be part of a multi-AP transmission that includes DL transmissions from AP 1404. Frame 1506 is similar to frame 1504. The same description above regarding frame 1504 applies to frame 1506.

[0191] Subsequently, AP 1402 can acquire the TXOP and initiate an inter-AP TXS operation by transmitting MRTT frame 1508 to APs 1404 and 1406. MRTT frame 1508 can have a format similar to the MU-RTS trigger frame 600 described above. In the example, MRTT frame 1508 can indicate the identifiers of APs 1404 and 1406 (e.g., in the corresponding AID12 subfield of the corresponding user information field of MRTT frame 1508) and the allocation time 1510 of the TXOP (e.g., in the corresponding allocation duration subfield of the user information field). Additionally, MRTT frame 1508 can indicate the TXS mode (e.g., in the trigger TXOP sharing mode subfield of the common information field of MRTT frame 1508). 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.

[0192] In an embodiment, MRTT frame 1508 may further indicate a time period 1524 within allocation time 1510 for multi-AP transmission. Multi-AP transmission may or may not include AP 1402. Multi-AP transmission may be a coordinated DL PPDU transmission performed by AP 1402 and one or more of APs 1404 and 1406. Alternatively, as Figure 15As shown, multi-AP transmission can be a coordinated DL PPDU transmission performed by APs 1404 and 1406. Coordinated DL PPDU transmission can include C-OFDMA transmission, coordinated spatial reuse (C-SR) transmission, coordinated beamforming (C-BF) transmission, or coordinated joint transmission. In an embodiment, multi-AP transmission can be a response to frames 1504 and 1506 from APs 1404 and 1406, respectively, which signal information about the corresponding DL transmissions from APs 1404 and 1406.

[0193] In one embodiment, MRTT frame 1508 may further indicate a time period 1526 for the first portion of the DL PPDU to be transmitted via DL from AP 1404 and / or via DL from AP 1406. In another 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. In yet another embodiment, time period 1526 corresponds to the transmission duration of the first portion of the DL PPDU. In yet another embodiment, time period 1526 may also be based on the DL transmission parameters indicated in frame 1504 and / or frame 1506.

[0194] In the example, a DL PPDU can have the following characteristics: Figure 12 The format shown is described. In an embodiment, the first part may include one or more of the following: L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and UHR-SIG of the DL PPDU. In an example, the first part includes L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and UHR-SIG of the DL PPDU. In another embodiment, the first part may include one or more of the following: L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, UHR-SIG, UHR-STF, and UHR-LTF of the DL PPDU. In an example, the first part includes L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, UHR-SIG, UHR-STF, and UHR-LTF of the DL PPDU.

[0195] In one embodiment, AP 1402 may determine a first length of the first portion of the DL PPDU based on the number of STAs indicated in frame 1504. In another embodiment, AP 1402 may determine a second length of the first portion of the DL PPDU based on the number of STAs indicated in frame 1506. In this example, based on the number of STAs indicated in frames 1504 / 1506, AP 1402 may determine the desired size (e.g., the number of OFDM symbols) of one or more fields of the first portion, which varies with the number of STAs served by the DL PPDU. Padding bits may be inserted in the middle of the first portion. For example, padding bits may be added at the end of the UHR-SIG field of the first portion, or within the UHR-SIG field, or just before the CRC field of the UHR-SIG. For example, AP 1402 may determine the required number / size of UHR-LTFs for the DL PPDU.

[0196] In one embodiment, AP 1402 may determine a first duration based on a first length of a first portion of the DL PPDU. In another embodiment, AP 1402 may determine a second duration based on a second length of the first portion of the DL PPDU. In yet another embodiment, AP 1402 may select the larger of the first and second durations as time period 1526. This ensures that time period 1526 is long enough to accommodate the DL traffic requirements of both APs 1404 and 1406. In another embodiment, time period 1526 may be limited by the maximum duration of the first portion of the PPDU. That is, time period 1526 cannot exceed the maximum duration. In yet another embodiment, AP 1402 may select the shorter of the first and second durations as time period 1526. This ensures that at least one of APs 1404 and 1406 can fully utilize time period 1526.

[0197] In an embodiment, MRTT frame 1508 may include the duration of time period 1526. In an embodiment, the start time of time period 1526 may be determined based on MRTT frame 1508. For example, the start time of time period 1526 may be the time elapsed after two SIFS plus CTS frame transmission times, starting from the time MRTT frame 1508 is received. The end time of time period 1526 may be determined based on the start time and the indicated duration.

[0198] In another embodiment, MRTT frame 1508 may include the start and end times of time period 1526, the start and duration of time period 1526, or the duration and end time of time period 1526. In this embodiment, the start time of time period 1526 may not be based on MRTT frame 1508.

[0199] In another embodiment, the MRTT frame 1508 may indicate the time period 1526 as a segment of the allocation time 1510. For example, the MRTT frame 1508 may indicate that the time period 1526 corresponds to the first half / first third / first quarter of the allocation time 1510, or the first X microseconds of the allocation time 1510, etc.

[0200] In another embodiment, the MRTT frame 1508 can indicate the time period 1526 by indicating the number of OFDM symbols to be transmitted during the time period 1526 (based on a given duration (e.g., 4 microseconds) of the OFDM symbols in the first part).

[0201] In other embodiments, AP 1402 may initiate inter-AP TXS operation by transmitting frames other than MRTT frames. For example, AP 1402 may use a multi-AP trigger frame to initiate inter-AP TXS operation. The multi-AP trigger frame may include / indicate the same information as described above included / indicated in MRTT frame 1508. APs 1404 and 1406 may respond to or acknowledge the multi-AP trigger frame from AP 1402, or may not respond to or acknowledge it.

[0202] like Figure 15 As 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 communicating using allocated time 1510 according to the TXS mode indicated in MRTT frame 1508 and taking into account time period 1524, without triggering from AP 1402. In example 1400, the TXS mode can allow APs 1404 and 1406 to communicate with AP 1402 or with another STA during allocated time period 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) Transmits (non-TB) DL PPDU 1516. When transmitting DL PPDU 1516, AP 1404 can use time period 1526 for the first part of DL PPDU 1516. AP 1404 can insert padding bits at the end of the first part to ensure that the transmission duration of the first part is equal to time period 1526. Similarly, AP 1406 can use time period 1524 to transmit to the associated STA (…). Figure 15(Not shown in the diagram) Transmit (non-TB) DL PPDU 1518. When transmitting DL PPDU 1518, AP 1406 can use time period 1526 for the first part of DL PPDU 1518. With time period 1526 set by AP 1402 as described above, AP 1406 may not need to insert any padding bits at the end of the first part of DL PPDU 1518, and can use time period 1526 entirely for the transmission of the first part of DL PPDU 1518. Therefore, the utilization of time allocation 1510, and especially the utilization of time period 1526, is improved.

[0203] In the example, AP 1404 can use the remaining duration of allocation time 1510 from the associated STA based on any indication in MRTT frame 1508. Figure 15 (Not shown in the image) receives UL PPDU 1520. In the example, AP 1406 can use the remaining duration of allocation time 1510 from the associated STA (not shown in the image) according to 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 the time period of the first portion of UL PPDUs 1520 and 1522. In an embodiment, AP 1404 may signal the time period to its associated STA that is scheduled to transmit UL PPDU 1520. In an embodiment, AP 1406 may signal the time period to its associated STA that is scheduled to transmit UL PPDU 1522.

[0204] In the 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 assign corresponding frequency resources that are 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 assigned to one of the corresponding APs, AP 1404 and 1406. In the example, the frequency resources assigned 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 transmitting DL PPDU 1518 and UL PPDU 1522.

[0205] Figure 16Example A-Control fields 1602 and 1604 that can be used in embodiments are shown. A-Control fields 1602 and 1604 can be used to carry in a QoS data frame / empty frame the number of STAs associated with the AP for DL ​​transmission and / or the duration of the first portion of the DL PPDU for DL ​​transmission. 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 the 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 “DL STA Count” field. The “DL STA Count” field indicates the number of STAs associated with the AP for DL ​​transmission as described above. In an embodiment, A-Control field 1604 includes a “Duration of the First Part of the DL PPDU” field. The “Duration of the First Part of the DL PPDU” field may include / indicate the duration of the DL transmission of the first part of the DL PPDU as described above.

[0206] Figure 17 Example information elements 1702 and 1704 that can be used in embodiments are shown. Information elements 1702 and 1704 can be used to carry in the action frame the number of STAs associated with the AP for DL ​​transmission and / or the duration of the DL transmission for the first part of the DL PPDU. 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 the 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 also includes a “DL STA Count” field. The “DL STA Count” field indicates the number of STAs associated with the AP for DL ​​transmission as described above. In an embodiment, information element 1704 also includes a “Duration of the First Part of the DL PPDU” field. The “Duration of the First Part of the DL PPDU” field may include / indicate the duration of the DL transmission of the first part of the DL PPDU as described above.

[0207] 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 18As shown, process 1800 includes steps 1802 and 1804.

[0208] Step 1802 includes receiving a first frame from the second AP by the first AP, the first frame indicating the number of STAs associated with the second AP for DL ​​transmissions from the second AP. In the example, the first AP and the second AP may form a multi-AP group. In the 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. DL transmissions may be part of multi-AP transmissions. Multi-AP transmissions may or may not include the first AP. Multi-AP transmissions may include the second AP and a third AP. The number of STAs indicated in the first frame may be STAs that the second AP intends or wishes to send to it in the DL transmission.

[0209] In one embodiment, the first frame may include an action frame. The action frame may include information elements, such as the number of STAs associated with the second AP. 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 associated with the second AP.

[0210] Step 1804: The first AP transmits a second frame to the second AP. The second frame indicates the time period for DL ​​transmission of the first portion of the DL PPDU. The DL PPDU may be part of a C-OFDMA DL 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 corresponds to the transmission duration of the first portion.

[0211] In an embodiment, the first part includes one or more of the following: L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and UHR-SIG. In an embodiment, the first part includes one or more of the following: L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, UHR-SIG, UHR-STF, and UHR-LTF.

[0212] 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.

[0213] In an embodiment, the first frame further indicates DL transmission parameters for the transmission of the first portion of the DL PPDU. The DL transmission parameters can be selected by the second AP from a plurality of DL transmission parameters. The DL transmission parameters can be suggested / preferred by the second AP for DL ​​transmission. The DL transmission parameters may include one or more of the following: modulation and coding scheme (MCS), bandwidth size, resource unit (RU) size, physical layer protocol data unit (PPDU) type, or number of spatial streams for the transmission of the first portion. In an embodiment, the time period may also be based on the DL transmission parameters.

[0214] In an embodiment, the first frame may include a DL BSR indicating the amount of DL traffic buffered at the second AP. The DL BSR may be a C-OFDMA BSR. In an embodiment, process 1800 may further include: transmitting a third frame requesting a DL BSR to the second AP; and receiving a first frame as a 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.

[0215] Figure 19 Another 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.

[0216] Step 1902 includes receiving a first frame from the second AP by the first AP, the first frame indicating the duration of a DL transmission of a first portion of a DL PPDU from the second AP to one or more STAs associated with the second AP. In the example, the first AP and the second AP may form a multi-AP group. In the 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. The DL transmission may be part of a multi-AP transmission. The multi-AP transmission may or may not include the first AP. The multi-AP transmission may include the second AP and a third AP. The number of STAs indicated in the first frame may be STAs that the second AP intends or wishes to send to in the DL transmission. The STAs may be STAs scheduled by the second AP.

[0217] In an embodiment, the first part includes one or more of the following: L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and UHR-SIG. In an embodiment, the first part includes one or more of the following: L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, UHR-SIG, UHR-STF, and UHR-LTF.

[0218] The duration indicated in the first frame can be preferred / recommended / selected by the second AP. In an embodiment, the duration can be based on the length of the first portion. The length of the first portion can include multiple OFDM symbols. In an embodiment, the unit / granularity of the OFDM symbols is [not specified].

[0219] Step 1904 includes transmitting a second frame from the first AP to the second AP indicating a time period of the first portion of the DL PPDU. In an embodiment, the time period is based on the duration indicated in the first frame.

[0220] 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 also include the identifier of the second AP.

[0221] Figure 20 Another example process 2000 according to an embodiment is shown. Example process 200 can be performed by a first AP (e.g., AP 1404 or 1406 described above). Figure 20 As shown, process 2000 includes steps 2002 and 2004.

[0222] Step 2002 involves transmitting a first frame from the first AP to the second AP, the first frame indicating the number of STAs associated with the first AP for DL ​​transmissions from the first AP. In the example, the first AP and the second AP may form a multi-AP group. In the 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. DL transmissions may be part of a multi-AP transmission. Multi-AP transmissions may or may not include the second AP. Multi-AP transmissions may include both the first AP and a third AP. The number of STAs indicated in the first frame may be STAs that the first AP intends or wishes to send to it in the DL transmission.

[0223] In one embodiment, the first frame may include an action frame. The action frame may include information elements, such as the number of STAs associated with the first AP. 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 associated with the first AP.

[0224] Step 2004 includes receiving a second frame from the second AP by the first AP, the second frame indicating a time period for DL ​​transmission of the first portion of the DL PPDU. The DL PPDU may be part of a C-OFDMA DL 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 corresponds to the transmission duration of the first portion.

[0225] In an embodiment, the first part includes one or more of the following: L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and UHR-SIG. In an embodiment, the first part includes one or more of the following: L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, UHR-SIG, UHR-STF, and UHR-LTF.

[0226] 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.

[0227] In an embodiment, the first frame further indicates DL transmission parameters for the transmission of the first portion of the DL PPDU. The DL transmission parameters can be selected by the first AP from a plurality of DL transmission parameters. The DL transmission parameters can be suggested / preferred by the first AP for DL ​​transmission. The DL transmission parameters may include one or more of the following: modulation and coding scheme (MCS), bandwidth size, resource unit (RU) size, physical layer protocol data unit (PPDU) type, or number of spatial streams for the transmission of the first portion. In an embodiment, the time period may also be based on the DL transmission parameters.

[0228] In an embodiment, the first frame may include a DL BSR indicating the amount of DL traffic buffered at the first AP. The DLBSR may be a C-OFDMA BSR. In an embodiment, process 2000 may further include: receiving a third frame requesting a DLBSR from a second AP by the first AP; and transmitting a first frame as a 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.

[0229] Figure 21 Another example process 2100 according to an embodiment is shown. Example process 2100 can be performed by a first AP (e.g., AP 1404 or 1406 described above). Figure 21 As shown, process 2100 includes steps 2102 and 2204.

[0230] Step 2102 involves transmitting a first frame from the first AP to the second AP, the first frame indicating the duration of a first portion of the DL PPDU being transmitted from the first AP to one or more STAs associated with the first AP via DL transmission. In the example, the first AP and the second AP may form a multi-AP group. In the 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. The DL transmission may be part of a multi-AP transmission. The multi-AP transmission may or may not include the second AP. The multi-AP transmission may include both the first AP and a third AP. The number of STAs indicated in the first frame may be STAs to which the first AP intends or wishes to transmit in the DL transmission. The STAs may be STAs scheduled by the first AP.

[0231] In an embodiment, the first part includes one or more of the following: L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and UHR-SIG. In an embodiment, the first part includes one or more of the following: L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, UHR-SIG, UHR-STF, and UHR-LTF.

[0232] The duration indicated in the first frame can be preferred / recommended / selected by the first AP. In an embodiment, the duration can be based on the length of the first portion. The length of the first portion can include multiple OFDM symbols. In an embodiment, the unit / granularity of the OFDM symbols is 4 μs.

[0233] Step 2104 includes receiving a second frame from the second AP indicating a time period of a first portion of the DL PPDU by the first AP. In an embodiment, the time period is based on the duration indicated in the first frame.

[0234] 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 also 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 station STAs associated with the second AP for downlink DL transmission from the second AP; as well as The first AP sends a second frame to the second AP, and the second frame indicates: The allocation time for the DL transmission of the transmission opportunity TXOP obtained by the first AP; The identifier of the second AP; as well as The time period for the DL transmission of the preamble of the downlink DL physical layer protocol data unit (PPDU) is based on the number of STAs.

2. A method comprising: The first access point (AP) receives a first frame from the second AP, the first frame indicating the number of station STAs associated with the second AP for downlink DL transmission from the second AP; as well as The first AP sends a second frame to the second AP, the second frame indicating the time period for the first part of the downlink DL physical layer protocol data unit (PPDU) to perform the DL transmission, the time period being based on the number of STAs.

3. The method of claim 2, wherein the second frame further indicates the allocation time of a 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 first frame further indicates DL transmission parameters for the transmission of the first portion of the DL PPDU.

6. The method of claim 5, wherein the time period is further based on the DL transmission parameters.

7. The method of claim 6, wherein the DL transmission parameters are selected by the second AP from a plurality of DL transmission parameters.

8. The method of claim 6, wherein the DL transmission parameters are suggested by the second AP for the DL transmission.

9. The method of claim 6, wherein the DL transmission parameters are preferably used by the second AP for the DL transmission.

10. The method according to any one of claims 5 to 9, wherein the DL transmission parameters include one or more of the modulation and coding scheme (MCS) for the transmission in the first part, bandwidth size, resource unit (RU) size, physical layer protocol data unit (PPDU) type, or number of spatial streams.

11. The method according to any one of claims 2 to 10, wherein the time period corresponds to the transmission duration of the first portion.

12. The method according to any one of claims 2 to 11, wherein the DL PPDU is part of a coordinated orthogonal frequency division multiple access (C-OFDMA) DL transmission.

13. The method of any one of claims 2 to 12, wherein the first frame includes a DL buffer status report (BSR) indicating the amount of DL traffic buffered at the second AP.

14. The method of claim 13, further comprising: The first AP sends a third frame requesting the DL 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.

15. The method of claim 14, wherein the third frame includes a Buffer Status Report Polling BSRP trigger frame, a basic trigger frame, a polling frame, or a request frame.

16. The method according to any one of claims 13 to 15, wherein the DL BSR is a Coordinated Orthogonal Frequency Division Multiple Access (C-OFDMA) BSR.

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 second frame further indicates an identifier of the second AP.

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

20. The method of claim 19, wherein the action frame includes an information element, the information element including the number of STAs associated with the second AP.

21. The method according to any one of claims 2 to 18, wherein the first frame comprises a Quality of Service (QoS) empty frame or a data frame.

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

23. The method according to any one of claims 2 to 22, wherein the first part comprises one or more of the following: L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and UHR-SIG.

24. The method according to any one of claims 2 to 22, wherein the first part comprises one or more of the following: L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, UHR-SIG, UHR-STF and UHR-LTF.

25. A method comprising: The first access point (AP) receives a first frame from the second AP, the first frame indicating the duration of a first portion of a downlink physical layer protocol data unit (DL PPDU) being transmitted from the second AP to one or more stations (STAs) associated with 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 time period of the first portion of the DL PPDU, the time period being the allocated time of the TXOP and based on the duration.

26. The method of claim 25, wherein the duration is selected by the second AP.

27. The method according to any one of claims 25 to 26, wherein the duration is based on the length of the first portion.

28. The method of claim 27, wherein the length of the first portion comprises a plurality of orthogonal frequency division multiplexing (OFDM) symbols.

29. The method of claim 28, wherein the unit of one OFDM symbol in the OFDM symbols is 4 μs.

30. The method according to any one of claims 25 to 29, wherein the one or more STAs include STAs scheduled by the second AP for the DL transmission.

31. The method according to any one of claims 25 to 30, wherein the DL transmission is part of coordinated orthogonal frequency division multiple access (C-OFDMA) transmission, coordinated spatial reuse (C-SR) transmission, coordinated beamforming (C-BF) transmission, or coordinated joint transmission.

32. The method according to any one of claims 25 to 31, wherein the first part comprises one or more of the following: L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and UHR-SIG.

33. The method according to any one of claims 25 to 31, wherein the first part comprises one or more of the following: L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, UHR-SIG, UHR-STF and UHR-LTF.

34. A method comprising: A first frame is sent from the first access point (AP) to the second AP, the first frame indicating the number of station STAs associated with the first AP for downlink DL transmission from 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 for the DL transmission of the transmission opportunity TXOP obtained by the second AP; The identifier of the first AP; as well as The first part of the DL physical layer protocol data unit (PPDU) is used for the time period of the DL transmission, the time period being based on the number of STAs.

35. A method comprising: A first frame is sent from the first access point (AP) to the second AP, the first frame indicating the number of station STAs associated with the first AP for downlink DL transmission from the first AP; as well as The first AP receives a second frame from the second AP, the second frame indicating the time period for the first part of the downlink DL physical layer protocol data unit (PPDU) to perform the DL transmission, the time period being based on the number of STAs.

36. The method of claim 35, wherein the second frame further indicates the allocation time of a transmission opportunity (TXOP) obtained by the second AP.

37. The method of claim 36, wherein the time period is the allocated time of the TXOP.

38. The method according to any one of claims 35 to 37, wherein the first frame further indicates DL transmission parameters for the transmission of the first portion of the DLPPDU.

39. The method of claim 38, wherein the time period is further based on the DL transmission parameters.

40. The method of claim 39, wherein the DL transmission parameters are selected by the first AP from a plurality of DL transmission parameters.

41. The method of claim 39, wherein the DL transmission parameters are suggested by the first AP for the DL transmission.

42. The method of claim 39, wherein the DL transmission parameters are preferably used by the first AP for the DL transmission.

43. The method according to any one of claims 38 to 42, wherein the DL transmission parameters include one or more of the modulation and coding scheme (MCS) for the transmission in the first part, bandwidth size, resource unit (RU) size, physical layer protocol data unit (PPDU) type, or number of spatial streams.

44. The method according to any one of claims 35 to 43, wherein the time period corresponds to the transmission duration of the first portion.

45. The method according to any one of claims 35 to 44, wherein the DL PPDU is part of a coordinated orthogonal frequency division multiple access (C-OFDMA) DL transmission.

46. ​​The method of any one of claims 35 to 45, wherein the first frame includes a DL buffer status report (BSR) indicating the amount of DL traffic buffered at the first AP.

47. The method of claim 46, further comprising: The first AP receives a third frame requesting the DL BSR from the second AP; as well as The first AP sends the first frame to the second AP as a response to the third frame.

48. The method of claim 47, wherein the third frame includes a Buffer Status Report Polling BSRP trigger frame, a basic trigger frame, a polling frame, or a request frame.

49. The method according to any one of claims 46 to 48, wherein the DL BSR is a Coordinated Orthogonal Frequency Division Multiple Access (C-OFDMA) BSR.

50. The method of any one of claims 35 to 49, 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.

51. The method according to any one of claims 35 to 50, wherein the second frame further indicates an identifier of the first AP.

52. The method according to any one of claims 35 to 51, wherein the first frame includes an action frame.

53. The method of claim 52, wherein the action frame includes an information element, the information element including the number of STAs associated with the first AP.

54. The method according to any one of claims 35 to 51, wherein the first frame comprises a Quality of Service (QoS) empty frame or a data frame.

55. The method of claim 54, wherein the QoS empty frame or data frame includes an aggregation control A-Control field, the aggregation control field including the number of STAs associated with the first AP.

56. The method according to any one of claims 35 to 55, wherein the first part comprises one or more of the following: L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and UHR-SIG.

57. The method according to any one of claims 35 to 55, wherein the first part comprises one or more of the following: L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, UHR-SIG, UHR-STF, and UHR-LTF.

58. A method comprising: A first frame is sent from the first access point (AP) to the second AP, the first frame indicating the duration of a first portion of a downlink physical layer protocol data unit (DL PPDU) being transmitted from the first AP to one or more stations (STAs) associated with 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 time period of the first portion of the DL PPDU, the time period being the allocated time of the TXOP and based on the duration.

59. The method of claim 58, wherein the duration is selected by the first AP.

60. The method according to any one of claims 58 to 59, wherein the duration is based on the length of the first portion.

61. The method of claim 60, wherein the length of the first portion comprises a plurality of orthogonal frequency division multiplexing (OFDM) symbols.

62. The method of claim 60, wherein the unit of the OFDMA symbol in the OFDM symbol is 4 μs.

63. The method according to any one of claims 58 to 62, wherein the one or more STAs include STAs scheduled by the second AP for the DL transmission.

64. The method according to any one of claims 58 to 63, wherein the DL transmission is part of coordinated orthogonal frequency division multiple access (C-OFDMA) transmission, coordinated spatial reuse (C-SR) transmission, coordinated beamforming (C-BF) transmission, or coordinated joint transmission.

65. The method according to any one of claims 58 to 64, wherein the first part comprises one or more of the following: L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and UHR-SIG.

66. The method according to any one of claims 58 to 64, wherein the first part comprises one or more of the following: L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, UHR-SIG, UHR-STF, and UHR-LTF.

67. An apparatus comprising: One or more processors; as well as A memory that stores instructions that, when executed by the one or more processors, cause the apparatus to perform the method according to any one of claims 1 to 66.

68. 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 66.

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