Coordinated time division multiple access (CTDMA) truncated procedure

Abstract

Methods and apparatuses for wireless networks are provided. One method includes transmitting, by a first access point (AP), a first frame to a first station (STA) during a portion of a transmit opportunity (TXOP) shared by the second AP with the first AP, receiving, by the first AP, a second frame from the first STA in response to the first frame, based on the second frame indicating that the first STA does not have buffered data for transmission to the first AP, transmitting, by the first AP, a third frame to the first STA that triggers transmission of a first truncated frame by the first STA for resetting a first basic network allocation vector (NAV) of a second STA, and transmitting, by the first AP, a second truncated frame for resetting a second basic NAV of a third STA.

Description

Background Technology

[0001] Wireless networks are often extremely busy with numerous devices "wanting" to transmit. This heavy occupancy of wireless media can lead to unacceptable delays or latency in some critical transmissions. In some networks, such as IEEE 802.11 (also known as 'Wi-Fi'), devices like access points (APs) can coordinate among themselves to improve media usage. Furthermore, many wireless networks overlap with and are subject to interference from other similar and different wireless networks.

[0002] This application claims priority to U.S. Provisional Applications US 63 / 548408, 63 / 557641 and 63 / 626551, the entire disclosure of which is incorporated herein by reference. Summary of the Invention

[0003] To reduce latency in wireless networks, methods, apparatus, and computer program products as defined in the appended claims are provided.

[0004] In one aspect, a method is provided comprising: transmitting a first frame from a first AP to a first station (STA) during a portion of a transmission opportunity (TXOP) shared by a second access point (AP) and a first AP; receiving a second frame from the first STA in response to the first frame by the first AP; based on the second frame indicating that the first STA does not have buffered data for transmission to the first AP: transmitting a third frame from the first AP to the first STA, the third frame triggering the transmission of a first truncated frame by the first STA for resetting a first basic network allocation vector (NAV) of a second STA; and transmitting a second truncated frame by the first AP for resetting a second basic NAV of a third STA.

[0005] In one aspect, a method is provided, comprising: receiving a first frame from a first station (STA) by the first AP during a portion of a transmission opportunity (TXOP) shared by a second access point (AP) and a first AP; transmitting a second frame to the first STA, based on the first frame indicating that the first STA does not have buffered data for transmission to the first AP, triggering the transmission of a first truncated frame by the first STA; and transmitting the second truncated frame by the first AP.

[0006] In one aspect, a method is provided comprising: receiving a first frame from a first AP during a portion of a transmission opportunity (TXOP) shared by a second access point (AP) and a first AP; transmitting a second frame obtained by the first STA in response to the first frame to the first AP, wherein the second frame indicates whether the first STA has buffered data for transmission to the first AP; receiving a third frame from the first AP by the first STA, the third frame triggering the transmission of a first truncated frame by the first STA for resetting a first basic network allocation vector (NAV) of the second STA; and transmitting the first truncated frame by the first STA.

[0007] In one aspect, a method is provided, comprising: transmitting a first frame from a first station (STA) to the first AP during a portion of a transmission opportunity (TXOP) shared by a second access point (AP) and a first AP, wherein the first frame indicates whether the first STA has buffered data for transmission to the first AP; and receiving from the first AP a second frame that triggers the transmission of the first truncated frame by the first STA.

[0008] In one aspect, a computer program product is provided that can be stored on a computer-readable medium and is configured to perform the methods disclosed herein when run on a computer.

[0009] In various respects, devices are provided that are arranged to function in access points (APs) and stations (STAs) of a wireless network, said devices being arranged to perform the methods disclosed herein.

[0010] In C-TDMA, one AP (the sharing AP) shares a TXOP with another AP (the shared AP). It is possible that the sharing AP may receive a trigger frame from the shared AP during the time slot allocated to the shared AP. This trigger frame has the effect of updating the basic NAV of the STA associated with the shared AP. The shared AP can then send a frame (e.g., a CF-end frame) back to the sharing AP to return the TXOP (i.e., release it). The STA associated with the shared AP can hear the frame from that STA, which allows it to reset its NAV and begin communication with its AP.

[0011] The inventors have recognized that problems can occur with STAs located outside the range of a shared AP but within the range of the shared AP, rather than as part of a multi-AP group. When the shared AP sends the first frame establishing the shared TXOP, it can set its NAV. Then, it hears a frame from the shared AP releasing or truncating the TXOP sent as part of a multi-AP group exchange and resets its NAV, which is undesirable because exchanges may be entering the multi-AP group. If the truncation of the first part of the TXOP is achieved via a frame from the shared AP and its STAs, then STAs outside the range of the shared AP and STAs do not reset their NAV, and the protection of the TXOP is preserved. Attached Figure Description

[0012] This document describes examples of several embodiments of various embodiments of the present disclosure with reference to the accompanying drawings.

[0013] Figure 1 An example wireless communication network in which embodiments of the present disclosure may be implemented is illustrated.

[0014] Figure 2 This is a block diagram illustrating an example implementation of a station (STA) and an access point (AP).

[0015] Figure 3 The illustration shows an example Media Access Control (MAC) frame format.

[0016] Figure 4 The illustration shows an example management frame that can be used as an action frame.

[0017] Figure 5 The illustration shows an example control frame that can be used as a trigger frame.

[0018] Figure 6 The illustration shows an example data frame that can be used as a Quality of Service (QoS) empty frame.

[0019] Figure 7 The illustration shows an example format of a Physical Layer (PHY) Protocol Data Unit (PPDU).

[0020] Figure 8 The illustration shows an example of a multi-AP network.

[0021] Figure 9 The illustration shows an example network that includes a set of coordinated APs.

[0022] Figure 10 The diagram illustrates a sample multi-AP operation process.

[0023] Figure 11 The illustration shows an example of a multi-AP probe phase.

[0024] Figure 12The illustration shows an example of the downlink data transmission phase in a multi-AP setup.

[0025] Figure 13 The illustration shows an example of the uplink data transmission phase in a multi-AP setup.

[0026] Figure 14 The illustration shows Enhanced Distributed Channel Access (EDCA) and Coordinated Time Division Multiple Access (CTDMA).

[0027] Figure 15 The illustration shows an example of a Multi-User Request Transmission (MU-RTS) trigger frame that can be used in a triggered Transmission Opportunity (TXOP) Share (TXS) process.

[0028] Figure 16 The illustration shows an example of a triggered TXS process (mode=1).

[0029] Figure 17 The illustration shows an example of a triggered TXS process (mode=2).

[0030] Figure 18 An example of an existing CTDMA procedure is illustrated.

[0031] Figure 19 Another example of an existing CTDMA procedure is illustrated.

[0032] Figure 20 Another example of the CTDMA process is illustrated.

[0033] Figure 21 Another example of the CTDMA process is illustrated.

[0034] Figure 22 An example of a CTDMA process according to an embodiment is illustrated.

[0035] Figure 23 Another example of the CTDMA process according to an embodiment is illustrated.

[0036] Figure 24 Another example of the CTDMA process according to an embodiment is illustrated.

[0037] Figure 25 An example process according to an embodiment is illustrated.

[0038] Figure 26 Another example process according to an embodiment is illustrated. Detailed Implementation

[0039] In this disclosure, various embodiments are presented as examples of how the disclosed techniques and / or how the disclosed techniques can be practiced in environments and scenarios. It will be apparent to those skilled in the art that various changes in form and detail can be made without departing from the scope. After reading the specification, those skilled in the art will understand how to implement alternative embodiments. This embodiment is not limited to any of the described exemplary embodiments. Embodiments of this disclosure will be described with reference to the accompanying drawings. Limitations, features, and / or elements from the disclosed example embodiments can be combined to create further embodiments within the scope of this disclosure. Any drawings highlighting features and advantages are presented for illustrative purposes only. The disclosed architecture is flexible and configurable enough that it can be used in ways other than those shown. For example, any actions listed in the flowcharts can be reordered or used only optionally in some embodiments.

[0040] The embodiments can be configured to operate as needed. The disclosed mechanisms can be executed when certain criteria are met, for example, in a station, access point, radio environment, network, or a combination thereof. 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, service characteristics, or a combination thereof. 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.

[0041] In this disclosure, “a” and “an” and similar phrases should 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” should be 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 employed by one or more embodiments in various embodiments. As used herein, the terms “comprising” and “consisting of” enumerate one or more components of the described element. The term “comprising” is interchangeable with “including” and does not exclude the inclusion of unlisted components in the described element. In contrast, “consisting of” provides a complete enumeration of one or more components of the described element. As used herein, the term “based on” can be interpreted as “at least partially based on” rather than, for example, “based on only.” The term “and / or” as used herein refers to 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.

[0042] If A and B are sets and every element of A is an element of B, then A is called a subset of B. In this specification, only non-empty sets and subsets are considered. For example, possible subsets of B = {STA1, STA2} are: {STA1}, {STA2}, and {STA1, STA2}. The phrase “based on” (or likewise “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 embodiments in various embodiments. The phrase “in response to” (or likewise “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 embodiments in various embodiments. The phrase “depends on” (or likewise “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 embodiments in various embodiments. The phrase “adopts / uses” (or likewise “adopts / uses at least”) indicates that the phrase following the phrase “adopts / uses” is an example of one of a variety of suitable possibilities that may or may not be used in one or more embodiments in various embodiments.

[0043] The term "configured" can refer to the capacity of a device, regardless of whether the device is in an operational or non-operational state. "Configured" can also refer to specific settings within a 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 a device, regardless of whether the device is in an operational or non-operational state, to provide specific characteristics to the device. Terms such as "control messages generated in the device" can mean that control messages have parameters that can be used to configure specific characteristics or to perform certain actions within the device, regardless of whether the device is in an operational or non-operational state.

[0044] 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 the example embodiments, when one or more messages / frames include multiple parameters, this means that a parameter among the multiple parameters is present in at least one of the one or more messages / frames, but not necessarily in every one of the one or more messages / frames.

[0045] Many of the features presented are described as optional using the word "may" or parentheses. For the sake of brevity and readability, this disclosure does not explicitly describe every permutation that can be obtained by selecting from the set of optional features. This disclosure will be interpreted as explicitly disclosing all such permutations. For example, a system described as having three optional features can be embodied in seven ways: having only one of the three possible features, having any two of the three possible features, or having three of the three possible features.

[0046] Many of the elements described in the disclosed embodiments can be implemented as modules. A module is defined herein as an element that performs a defined function and has a defined interface to other elements. Modules described in this disclosure can be implemented in hardware, software combined with hardware, firmware, wet hardware (e.g., hardware with biological elements), or combinations thereof, and 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). Modules can be implemented using physical hardware that combines 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, and C++. FPGAs, ASICs, and CPLDs are typically programmed using a hardware description language (HDL) (e.g., VHSIC Hardware Description Language (VHDL) or Verilog), which configures the connections between internal hardware modules with a limited set of functions on the programmable device. The techniques mentioned are often used in combination to implement the result of functional modules.

[0047] Figure 1 An example wireless communication network in which embodiments of the present disclosure may be implemented is illustrated.

[0048] like Figure 1 As shown, an 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.

[0049] BSS 110-1 and 110-2 each comprise a set of access points (APs or AP STAs) and at least one station (STAs or non-AP STAs). For example, BSS 110-1 includes AP 104-1 and STA 106-1, and BSS 110-2 includes AP 104-2 and STAs 106-2 and 106-3. The APs and at least one STA in the BSS perform an association procedure to communicate with each other.

[0050] The DS 130 can be configured to connect BSS 110-1 and BSS 110-2. In this way, the DS 130 can enable Extended Service Set (ESS) 150. Within the ESS 150, APs 104-1 and 104-2 are connected via the DS 130 and can have the same Service Set Identifier (SSID).

[0051] 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 be used as a bridge to connect DS 130 of WLAN infrastructure network 102 to other networks 108.

[0052] Figure 1 The example wireless communication network shown may also include one or more ad-hoc networks or standalone BSSs (IBSSs). An ad-hoc network or IBSS is a network of multiple STAs that are 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., not via an AP).

[0053] 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 include an AP, it does not include a centralized management entity. Instead, STAs within the IBSS are managed in a distributed manner. STAs forming an IBSS can be fixed or mobile.

[0054] A STA, serving as a predefined functional medium, may include a Media Access Control (MAC) layer conforming to the IEEE 802.11 standard. A physical layer interface for the radio medium can be used between APs and non-AP stations (STAs). STA 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) transmission.

[0055] A Physical Layer (PHY) Protocol Data Unit (PPDU) can be a composite structure including a PHY preamble and a PLCP Service Data Unit (PSDU) payload. For example, a PSDU may include a PHY Convergence Protocol (PLCP) preamble and header and / or one or more MAC Protocol Data Units (MPDUs). The receiving device can use the information provided in the PHY preamble to decode subsequent data in the PSDU. When transmitting a PPDU 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 may include both a legacy portion (or "legacy preamble") and a non-legacy portion (or "non-legacy preamble"). The legacy preamble can be used for packet detection, automatic gain control, and channel estimation, among other things. It is also typically used to maintain compatibility with legacy equipment. The format, encoding, and information provided in the non-legacy portion of the preamble are based on the specific IEEE 802.11 protocol to be used to transmit the payload.

[0056] A frequency band can include 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 revisions can be transmitted in 2.4 GHz, 5 GHz, and / or 6 GHz frequency bands, each of which can be divided into multiple 20 MHz channels. PPDUs can be transmitted on physical channels with a minimum bandwidth of 20 MHz. Larger channels can be formed through channel bonding. For example, PPDUs can be transmitted on physical channels with bandwidths of 40 MHz, 80 MHz, 160 MHz, or 520 MHz by bonding multiple 20 MHz channels together.

[0057] Figure 2 This is a block diagram illustrating an example implementation of 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.

[0058] 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. One or more processors and / or one or more controllers may include, for example, general-purpose processors, digital signal processors (DSPs), microcontrollers, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), logic circuits, or chipsets.

[0059] Memory 230 / 280 may include read-only memory (ROM), random access memory (RAM), flash memory, memory cards, storage media, 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 operations / embodiments discussed in this application. Memory 230 / 280 may be implemented (or located) within or outside of processor 220 / 270. Memory 230 / 280 may be operatively connected to processor 220 / 270 via various means known in the art.

[0060] 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. Thus, STA 210 and / or AP 260 can each implement multiple PHY layers. Multiple PHY layers can be implemented using one or more of transceivers 240 / 290.

[0061] Figure 3The illustration shows an example format for MAC frame 300. In operation, the STA can construct a subset of MAC frames for transmission and can decode a subset of received MAC frames during verification. The specific subset of frames that the STA can construct and / or decode can be determined by the functions supported by the STA. The STA can use the Frame Check Sequence (FCS) contained in the frame to verify received MAC frames and can interpret certain fields from the MAC header of all frames.

[0062] like Figure 3 As shown, MAC frame 300 includes a MAC header, a variable-length frame body, and a frame check sequence (FCS).

[0063] The MAC header includes a frame control field, an optional duration / ID field (not in PS-Poll frames), an address field, an optional sequence control field, an optional QoS control field (only in QoS data frames), and an optional high throughput (HT) control field (only in +HTC frames).

[0064] 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 high throughput control (+HTC).

[0065] The protocol version subfield remains unchanged in size and layout across all revisions of the IEEE 802.11 standard. For MAC frames, the value of the protocol version subfield is 0.

[0066] 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 underlying 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, which is a data frame that includes a 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.

[0067] The "To DS" subfield indicates whether the data frame is destined for the Distribution System (DS). The "From DS" subfield indicates whether the data frame originated from the DS.

[0068] In all data or management frames where the MAC Service Data Unit (MSDU) or MAC Management Protocol Data Unit (MMPDU) carried by the MAC frame has another fragment to follow, set the More Fragments subfield to 1. In all other frames where the More Fragments subfield exists, set it to 0.

[0069] The retry subfield is set to 1 in any data or management frame that is a retransmission of an earlier frame. It is set to 0 in all other frames in which the retry subfield exists. The receiving STA uses this indication to aid in its process of eliminating duplicate frames. These rules do not apply to frames transmitted by the STA under the block protocol.

[0070] The power management subfield is used to indicate the power management mode of the STA.

[0071] The More Data subfield indicates to the STA in Power Saving (PS) mode that a bufferable unit (BU) is buffered for that STA at the AP. The More Data subfield is valid in individually 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 the presence of at least one additional buffered BU for the STA.

[0072] If the frame body field contains information that has already been processed by the cryptographic encapsulation algorithm, then the protected frame subfield is set to 1.

[0073] The +HTC subfield indicates that MAC frame 300 contains the HT control field. Frames containing the HT control field are called +HTC frames. Control wrapper frames are +HTC frames.

[0074] The Duration / ID field in the MAC header indicates various aspects 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 transmitting the frame in 14 least significant bits (LSBs), and both most significant bits (MSBs) are set to 1. In other frames sent by the STA, the Duration / ID field contains a duration value (in microseconds) that is used by the receiver to update the Network Allocation Vector (NAV). The NAV is a counter that indicates to the STA the amount of time it must postpone access to the shared medium.

[0075] A MAC frame 300 format may contain up to four address fields. These fields are used to indicate the Basic Service Set Identifier (BSSID), source address (SA), destination address (DA), transmitter address (TA), and receiver address (RA). Some frames may not contain some of these address fields. Some address fields are specified using the relative positions of address fields (1-4) within the MAC header, regardless of the address type present in that field. Specifically, address 1 always identifies the intended receiver of the frame, and address 2 (if present) always identifies the transmitter of the frame.

[0076] The sequence control field consists of two subfields: the sequence number subfield and the 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. The fragment number is set to 0 in the first or only fragment of the MSDU or MMPDU and increments by 1 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 unsegmented MSDU or MMPDU, the fragment number is set to 0. The fragment number remains constant throughout all retransmissions of the fragment.

[0077] The QoS control field identifies the Service Category (TC) or Service Flow (TS) to which the MAC frame 300 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 STA being transmitted. The QoS control field exists in all data frames where the QoS subfield of the subtype subfield is equal to 1.

[0078] The HT control field exists in QoS data, QoS empty, and management frames, as determined by the +HTC subfield of the frame control field. The control frame subtype containing the HT control field is the control wrapper frame. A control frame described as +HTC (e.g., Request to Send (RTS) +HTC, Clear to Send (CTS) +HTC, Block Ack +HTC, or Block Ack Req +HTC frame) means that a control wrapper frame is used to carry that control frame.

[0079] The frame body field is a variable-length field that contains information specific to the individual frame type and subtype. It can include one or more MSDUs or MMPDUs. The minimum length of the frame body is 0 octets.

[0080] The FCS field contains a 32-bit Cyclic Redundancy Check (CRC) code. The FCS field value is calculated from all fields in the MAC header and frame body.

[0081] Figure 4 The illustration shows an example management frame 400 that can be used as an action frame. In the example, management frame 400 includes a MAC header, a variable-length frame body, and a Frame Check Sequence (FCS). The MAC header includes a frame control field, a duration field, an address 1 field, an address 2 field, an address 3 field, a sequence control field, and an optional HT control field. The presence of the HT control field is determined by the setting of the +HTC subfield of the frame control field.

[0082] like Figure 4 As shown, when used as an action frame, the frame body of a management frame includes an action field, a vendor-specific element, a Management Message Integrity Code (MME) element, a Message Integrity Code (MIC), and an Authenticated Mesh Peer Exchange element.

[0083] The action field includes a category field and an action details field. The action field provides a mechanism for specifying extended management actions. The category field indicates the category of the action frame. The action details field contains details of the action requested by the action frame. For example, the action frame could be a common action frame. Figure 4 As shown, in the common action frame format, the action details field is included in the common action field in eight bytes immediately following the category field, followed by the variable-length common action details field.

[0084] Optionally, one or more supplier-specific elements may exist. These elements are not present when the category subfield of the action field is supplier-specific.

[0085] When negotiating management frame protection, an MME exists, the frame is a group-addressed robust action frame, and (MBSS only) the action frame's class does not support group-addressed privacy as indicated by the class value; otherwise, it does not exist.

[0086] If a shared pairwise master key (PMK) exists between the sender and receiver of a self-protection action frame, the MIC element is present in the frame; otherwise, it is not.

[0087] If a shared PMK exists between the sender and receiver of a self-protection action frame, then the authenticated mesh peer-to-peer exchange element is present in the frame; otherwise, it is not.

[0088] Figure 5 The illustration shows an example format of trigger frame 500. Trigger frame 500 can be used by an AP to allocate resources for one or more STAs and to request one or more TBPPDU transmissions from them. Trigger frame 500 may also carry additional information required by a STA to transmit a TBPPDU to the AP.

[0089] like Figure 5 As shown, the trigger frame 500 includes a frame control field, a duration field, a receiver address (RA) field, a transmitter address (TA) field, a public information field, a user information list field, a padding field, and an FCS field.

[0090] 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.

[0091] The duration field indicates various aspects 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 field carries the association identifier (AID) of the STA transmitting the 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 field contains a duration value (in microseconds) that the receiver uses to update the Network Allocation Vector (NAV).

[0092] The RA field is the address of the STA intended to receive the incoming transmission from the transmission station. If trigger frame 500 is addressed to an STA belonging to a single BSS, the TA field is the address of the STA that transmitted trigger frame 500. If trigger frame 500 is addressed to an STA from at least two different BSSs from a set of multiple BSSIDs, the TA field is the transmitted BSSID.

[0093] The common information field specifies the trigger frame type of trigger frame 500, the transmission power of trigger frame 500 in dBm, and several key parameters of the TB PPDU transmitted by the STA in response to trigger frame 500. The trigger frame type used by the AP to receive QoS data using the UL MU is called the basic trigger frame. Non-EHT, non-AP HE STAs interpret the common information field as an HE variant. If B54 and B55 in the common information field are equal to 1, non-AP EHT STAs interpret the common information field as an HE variant; otherwise, they interpret it as an EHT variant. The HE variant common information field and the EHT variant common information field use the same encoding method for trigger type, UL length, additional TF, CS requirement, LDPC extra symbol segment, AP TX power, FEC prepare factor, PE disambiguation, and trigger-related common information subfields.

[0094] The user information list field contains zero or more user information fields. There are three variations of the user information field: special user information field, EHT variant user information field, and HE variant user information field.

[0095] The Special User Information field is a user information field that carries extended public information not provided in the Public Information field but does not carry user-specific information. If the Special User Information field is included in the trigger frame, the Special User Information Field Flag subfield of the EHT Variant Public Information field is set to 0; otherwise, it is set to 1. The Special User Information field is identified by the AID12 value 2007 and optionally exists in the trigger frame generated by the EHT AP. The Special User Information field (if present) immediately follows the Public Information field in the trigger frame and carries information for the U-SIG field of the requested EHT TB PPDU. The PHY Version Identifier subfield indicates the PHY version of the requested TB PPDU, which is not an HE TB PPDU. For EHT, the PHY Version Identifier subfield is set to 0. Other values ​​from 1 to 7 are reserved. The UL Bandwidth (BW) Extended subfield and the UL BW subfield in the Public Information field indicate the bandwidth of the requested TB PPDU from the addressed EHT STA (i.e., the bandwidth in the U-SIG field of the EHT TB PPDU). The EHT Space Reuse n subfield carries the value from the corresponding Space Reuse n subfield to be included in the U-SIG field of the EHT TBPPDU. The U-SIG Ignore and Verify subfield carries the value from the Ignore and Verify subfield of the U-SIG field of the requested EHT TBPPDU. The presence and length of the Trigger-Related User Information subfield in the Special User Information field depend on the variant of the trigger frame.

[0096] The EHT variant user information field is included in the user information field for each STA addressed in trigger frame 500. Each STA user information field includes the AID12 subfield, RU allocation subfield, UL FEC coding type subfield, UL EHT-MCS subfield, reservation subfield, spatial stream (SS) allocation / RA-RU information subfield, UL target received power subfield, and power saving (PS) 160 subfield (for use by the STA in the TB PPDU transmitted in response to trigger frame 500), as well as trigger-related user information subfields, etc. The RU allocation subfield in the EHT variant user information field of trigger frames that are not MU-RTS trigger frames, as well as the UL BW subfield in the common information field, the UL BW extension subfield in the special user information field, and the PS160 subfield in the EHT variant user information field, identify the size and location of the RU or MRU. The values ​​of the PS160 subfield and B0 in the RU allocation subfield indicate an 80MHz frequency subblock, where the RU or MRU is located in the 26-tone RU, 52-tone RU, 106-tone RU, 242-tone RU, 484-tone RU, 996-tone RU, 52br 26-tone RU, and 106+26-tone RU. The value of the PS160 subfield indicates the 160 MHz segment in which the RU or MRU of the 2996-tone RU, 996+484-tone MRU, and 996+484+242-tone MRU resides. The UL FEC encoding type subfield in the User Information field indicates the code type of the requested EHT TB PPDU. The UL FEC encoding type subfield is set to 0 to indicate BCC and set to 1 to indicate LDPC. The UL EHT MCS subfield in the User Information field indicates the EHT MCS of the requested EHT TB PPDU. The SS allocation subfield of the EHT variant user information field indicates the spatial flow of the requested EHT TB PPDU. The UL target received power subfield indicates the expected received signal power of the EHT portion of the EHT TB PPDU, measured at the AP's antenna connector and averaged on the antenna, transmitted over the allocated RU. The AP can use the trigger-related user information subfield to specify the preferred access class (AC) for each STA. The preferred AC setting can be determined by the minimum priority AC traffic transmitted by the participating STAs. The AP determines the list of participating STAs, as well as BW, MCS, RU allocation, SS allocation, Tx power, preferred AC, and the maximum duration of the TB PPDU for each participating STA. The RA-RU information subfield is reserved in the EHT variant user information field.

[0097] The padding field is optionally present in the trigger frame 400 to extend the frame length, giving the receiver STA sufficient time to prepare a response for transmitting an SIFS after receiving the frame. The padding field (if present) is at least two octets long and is set to all 1s.

[0098] The FCS field is used by the STA to verify received frames and interpret certain fields from the MAC header of the frame.

[0099] Figure 6 The illustration shows an example data frame 600 that can be used as a QoS empty frame. A QoS empty frame is a QoS data frame with an empty frame body. A QoS empty frame includes a QoS control field and an optional HT control field, which may contain a Buffer Status Report (BSR) control subfield. QoS empty frames indicating buffer status information can be transmitted from the STA to the AP.

[0100] QoS control fields may include a Service Identifier (TID) subfield, an Acknowledgment (Ack) policy indicator subfield, and a queue size subfield (or a Transmission Opportunity (TXOP) duration request subfield).

[0101] The TID subfield identifies the TC or TS 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., allowed values ​​of 0 to 7 for Enhanced Distributed Channel Access (EDCA) access policies to identify the user priority of the TC or TS).

[0102] The Ack policy indicator subfield, along with other information, identifies the acknowledgment policy followed during MPDU delivery (e.g., normal Ack, implicit block Ack request, no Ack, block Ack, etc.).

[0103] The queue size subfield is an 8-bit field that indicates the amount of buffered traffic at the STA for a given TC or TS to be transmitted to the AP identified by the receiver address of the frame containing the subfield. The queue size subfield is present in QoS empty frames transmitted by the STA when bit 4 of the QoS control field is set to 1. The AP can use the information contained in the queue size subfield to determine the duration of a TXOP allocated to the STA or to determine the uplink (UL) resources allocated to the STA.

[0104] In frames transmitted by or to an inefficient (non-HE) STA, the following rules may be applied to the queue size value:

[0105] The queue size value is an approximate total size of all MSDUs and A-MSDUs (excluding MSDUs or A-MSDUs included in the current QoS data frame) buffered at the STA in the delivery queues used for MSDUs and A-MSDUs, rounded up to the nearest multiple of 256 octets and represented in units of 256 octets, where the TID value is equal to the value indicated in the TID subfield of the QoS control field.

[0106] A queue size value of 0 is only used to indicate that there are no buffered transactions in the queue used for the specified TID.

[0107] The queue size value of 254 is used for all sizes greater than 64,768 octets.

[0108] The queue size value of 255 is used to indicate an unspecified or unknown size.

[0109] In frames sent from HE STA to HE AP, the following rules can be applied to queue size values.

[0110] The queue size value QS is an approximate total size in octet 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), where the TID value is equal to the value indicated in the TID subfield of the QoS control field.

[0111] The queue size subfield includes the scaling factor subfield in bits B14-B15 of the QoS control field and the unscaled value UV in bits B8-B13 of the QoS control field. The scaling factor subfield provides the scaling factor SF.

[0112] The STA obtains the queue size QS from the received QoS control field, which contains the scaling factor SF and the unscaled value UV, as shown below: QS= 16×UV, if SF equals 0; 1024 + 256 × UV, if SF equals 1; 17 408 + 2048 × UV, if SF equals 2; 148 480+32 768×UV, if SF equals 3 and UV is less than 62; >2 147 328, if SF equals 3 and UV equals 62; Unspecified or unknown if SF equals 3 and UV equals 63.

[0113] The TXOP Duration Request subfield, which can be included in place of the Queue Size subfield, indicates the duration in 32 microseconds (µs) that the sending STA needs to determine for the next TXOP for the specified TID. The TXOP Duration Request subfield is set to 0 to indicate that no TXOP is requested for the specified TID during the current Service Hour (SP). The TXOP Duration Request subfield is set to a non-zero value to indicate the requested TXOP duration in increments of 32 µs, ranging from 32 µs to 8160 µs.

[0114] HT control fields can include aggregate control (AC control) subfields. A-control subfields can include control list subfields that contain one or more control subfields.

[0115] The control subfield can be a BSR control subfield, which can contain buffer status information used for UL MU operations. The BSR control subfield can be formed by the Access Class Index (ACI) bitmap subfield, incremental TID subfield, ACI high subfield, scaling factor subfield, queue size high subfield, and all queue size subfields of the HT control field.

[0116] 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 all subfields of the queue size, otherwise it is set to 0, except that if the ACI bitmap subfield is 0 and the incremental TID subfield is 3, then the buffer status of all 8 TIDs is included.

[0117] The incremental TID subfield, together with the value of the ACI bitmap subfield, indicates the number of TIDs that the STA is reporting the buffer status for.

[0118] The ACI high subfield indicates the ACI of the AC of the BSR in the queue size high subfield. The ACI to AC mapping is defined as ACI value 0 mapping to AC_BE, ACI value 1 mapping to AC_BK, ACI value 2 mapping to AC_VI, and ACI value 3 mapping to AC_VO.

[0119] The scaling factor subfield indicates the queue size height and the unit SF (in octet bytes) of all queue size subfields.

[0120] The queue size high subfield indicates the buffered traffic (in SF octets) of the AC identified by the ACI high subfield, which is intended for use by the STA identified by the receiver address of the frame containing the BSR control subfield.

[0121] The queue size all subfields indicate the amount of buffered traffic (in SF octets) of all ACs identified by the ACI bitmap subfield, which is intended for use by the STA identified by the receiver address of the frame containing the BSR control subfield.

[0122] The queue size values ​​in both the queue size high and queue size all subfields are the total size of all MSDUs and A-MSDUs buffered at the STA in the delivery queues of the MSDUs and A-MSDUs associated with the AC, as specified in the ACI high and ACI bitmap subfields respectively, including MSDUs or A-MSDUs contained in the same PSDU as the frame containing the BSR control subfield, rounded up to the nearest multiple of the SF octet.

[0123] A queue size value of 254 in both the queue size high and all queue size subfields indicates that the amount of buffered traffic is greater than 254 × SF octets. A queue size value of 255 in both the queue size high and all queue size subfields indicates that the amount of buffered traffic is unspecified or unknown. The queue size value for QoS data frames containing fragments can remain constant, even if the amount of queued traffic changes as consecutive fragments are transmitted.

[0124] The MAC service provides the ability to exchange MSDUs with peer entities. To support this service, the local MAC uses an underlying PHY-level service to transport MSDUs to peer MAC entities. This asynchronous MSD transport is performed on a connectionless basis.

[0125] Figure 7 The diagram illustrates an example format of a PPDU. As shown, a PPDU may include a PHY preamble, a PHY header, a PSDU, and a tail and padding bits.

[0126] A PSDU may include one or more MPDUs, such as a QoS data frame, an MMPDU, a MAC control frame, or a QoS empty frame. When an MPDU carries a QoS data frame, the frame body of the MPDU may include an MSDU or an A-MSDU.

[0127] By default, MSDU delivery is based on best-effort. That is, there is no guarantee that the delivered MSDU will be successfully delivered. However, QoS facilities use Service Identifiers (TIDs) to specify differentiated services based on each MSDU.

[0128] The STA can differentiate MSDU delivery based on the specified service category (TC) or service flow (TS) of an individual MSDU. The MAC sublayer entity determines the user priority (UP) for 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 sequence of priorities, where 1 is the lowest value, 7 is the highest value, and 0 falls between 2 and 3.

[0129] MSDUs with a specific UP are referred to as belonging to the service category of that UP. Each MSDU at the Media Access Control Service Access Point (MAC SAP) can be provided directly to the UP in the UP parameters. A-MPDUs can include MPDUs with different TID values.

[0130] The STA can deliver Buffer Status Reports (BSRs) to assist the AP in allocating 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 deliver a BSR (requested BSR) in a frame transmitted to the AP in response to a BSR P trigger frame.

[0131] 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, incremental TID, high-priority AC, and two queue sizes.

[0132] The STA can report the buffer status of transmitted QoS empty frames and QoS data frames to the AP in the QoS control field, and report the buffer status of transmitted QoS empty frames, QoS data frames and management frames to the AP in the BSR control subfield (if present), as defined below.

[0133] 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 that 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.

[0134] If the AP has indicated its support for the receive BSR control subfield, the STA can report the buffer status in the BSR control subfield of the transmitted frame.

[0135] The High Efficiency (HE) STA can report the queue size for the preferred AC, as 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 that AC.

[0136] The HE STA can report the queue size for an AC, indicated by the ACI bitmap field in all subfields of the queue size control subfield. The STA can set all subfields of queue size to 255 to indicate unknown / unspecified BSRs for those ACs.

[0137] A multi-link device (MLD) is an entity capable of managing communication on multiple links. An MLD can be a logical entity and can have more than one affiliated station (STA). An MLD can be an access point MLD (AP MLD), where the STAs affiliated with the MLD are AP STAs (or APs). An MLD can also be a non-access point MLD (non-AP MLD), where the STAs affiliated with the MLD are non-AP STAs (or STAs).

[0138] Depending on the capabilities of both the communication AP MLD and the non-AP MLD, communication across different frequency bands / channels can occur simultaneously or at different times.

[0139] An MLD can have a single MAC service access point (MAC-SAP) to the LLC layer, which includes MAC data services. An MLD can support multiple MAC sub-layers coordinated by a Sub-Layer Management Entity (SME). Each APSTA (or non-AP STA) attached to an AP MLD (or non-AP MLD) has a different MAC address within the MLD.

[0140] The SME is responsible for coordinating the MAC sublayer management entity (MLME) of the MLD's affiliated STA to maintain a single Robust Secure Network Association (RSNA) key management entity and a single IEEE 802.1X authenticator or requester for multi-link operation (MLO).

[0141] The Multi-Link Operation (MLO) procedure allows MLD pairs to discover, synchronize, (de)authenticate, (re)associate, disassociate, and manage each other's resources on any common frequency band or channel supported by two MLDs. The authenticator and MAC-SAP of an AP MLD can be identified by the same AP MLD MAC address. The requester and MAC-SAP of a non-AP MLD can be identified by the same non-AP MLD MAC address.

[0142] Figure 8The illustration shows an example multi-AP network 800. The example multi-AP network 800 can be a multi-AP network according to the Wi-Fi Alliance standard specifications for multi-AP networks. For example... Figure 8 As shown, the multi-AP network 800 may include a multi-AP controller 802 and multiple multi-AP groups (or multi-AP sets or AP candidate sets), including multi-AP group 804, multi-AP group 806 and multi-AP group 808.

[0143] The multi-AP controller 802 can be a logical entity that implements the logic for controlling the APs in the multi-AP network 800. The multi-AP controller 802 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 802 can also provide loading functionality to load APs and provide them to the multi-AP network 800.

[0144] Multiple AP groups 804, 806, and 808 can each include multiple APs. APs in a multiple AP group are within each other's communication range. However, APs in 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.

[0145] In one approach, one of the APs in a multi-AP group can be designated as the master AP. The designation of the master AP can be done by the multi-AP controller 802 or by the APs in the multi-AP group. The master AP of the multi-AP group can be fixed or can change over time among the APs in the group. APs that are not the master AP of the multi-AP group are referred to as slave APs.

[0146] In one approach, a multi-AP group or AP candidate set is a set of APs that can initiate or participate in multi-AP coordination. APs in a multi-AP group can participate as slave APs in multi-AP coordination initiated by a master AP in the same multi-AP group. At least one AP in the multi-AP group should be able to act as a master AP.

[0147] In one approach, the APs in a multi-AP group can coordinate with each other, including coordinating transmissions within the multi-AP group. One aspect of this coordination may include coordination for performing multi-AP transmissions within the multi-AP group. As used herein, a multi-AP transmission is a transmission event in which multiple APs (in a multi-AP group or multi-AP network) transmit simultaneously over a time period. The time period for simultaneous AP transmissions can be consecutive time periods.

[0148] Multi-AP group coordination can be enabled by a multi-AP controller and / or by the master AP of the multi-AP group. In one approach, the multi-AP controller and / or the master AP can control time and / or frequency sharing within a TXOP. For example, when one of the APs in the multi-AP group (e.g., the master AP) acquires a TXOP, the multi-AP controller and / or the master AP can control how the time / frequency resources of the TXOP are shared with other APs in the multi-AP group. In one implementation, the AP that acquires the TXOP in the multi-AP group 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.

[0149] Multi-AP operation can be enabled by at least two APs that support multi-AP coordination within one or more multi-AP groups. APs can support multi-AP transmission schemes in a multi-AP network. The master AP can coordinate with slave APs to implement multi-AP coordination and support multi-AP transmission. Slave APs can participate in multi-AP transmission. The master AP can select slave APs suitable for multi-AP transmission. Slave APs can be candidates for multi-AP transmission prior to being specified by the master AP.

[0150] Multi-AP transmission schemes may include transmission schemes such as coordinated OFDMA, coordinated time division multiple access (TDMA), coordinated spatial reuse, coordinated beamforming, joint transmission or reception (JT / JR), or a combination of two or more of the aforementioned schemes.

[0151] Coordinated OFDMA (COFDMA) and Coordinated TDMA (CTDMA) can be classified as coordinated TXOP, where the frequency or time resources of TXOP can be used to coordinate interference. Coordinated Spatial Reuse (CSR) can provide reuse of the spatial domain of adjacent BSSs by adjusting the transmit power of the coordinated AP. Coordinated Beamforming (CBF) can provide dedicated null control with spatial radiation to suppress interference by means of multiple antennas based on channel state information (CSI) feedback from the coordinated AP. JT / JR can use distributed MIMO precoding or detection for data streams between multiple APs via shared CSI.

[0152] Figure 9 The diagram illustrates an example network 900 that includes a set of coordinated access points. Figure 9 As shown, a coordinated AP set may include AP 902-1 and AP 902-2. The coordinated AP set may be a subset of the established multi-AP group. At least one STA may be associated with each of APs 902-1 and 902-2. For example, STA 904-1 may be associated with AP 902-1, and STA 904-2 may be associated with AP 902-2.

[0153] AP 902-1 and 902-2 can belong to the category mentioned above. Figure 1 The same ESS described in [the original text]. In such a case, AP902-1 and 902-2 can be connected via DS to support ESS features. Furthermore, as part of a coordinated AP set, AP 902-1 and 902-2 can be connected via backhaul. Backhaul is used to quickly share information between APs to support coordinated transmission. The shared information can be channel state information or data to be sent to the associated STA. Backhaul can be wired or wireless. Wired backhaul is preferred for high-capacity information transmission without burdening the AP's main radio. However, wired backhaul may require higher deployment costs and may impose greater constraints on AP placement. Wireless backhaul is preferred due to its lower deployment costs and flexibility regarding AP placement. However, because wireless backhaul relies on the AP's main radio to transmit information, the AP cannot transmit or receive any data while using wireless backhaul.

[0154] Typically, one of APs 902-1 and 902-2 can act as the primary AP, while the other acts as the secondary AP. The primary AP is the AP that owns the TXOP. The primary AP shares frequency resources with the secondary AP during the TXOP. When there are more than two APs in the coordination set, the primary AP may share its TXOP with only a subset of the coordination set of APs. The role of the primary AP can change over time. For example, the primary AP role can be assigned to a specific AP for a period of time. Similarly, the secondary AP role can be dynamically selected by the primary AP or pre-assigned for a period of time.

[0155] Depending on the capabilities of the APs in the coordinated AP set, an AP may perform only a certain type of coordinated transmission. For example, in Figure 9 In this context, if AP 902-1 supports JT and CSR, while AP 902-2 supports CSR and CBF, then both APs can execute CSR alone as a coordinated transmission scheme. If the benefits of coordinated transmission do not outweigh some of its disadvantages, such as reduced flexibility and increased computational power required, then the APs may prefer to execute a single AP transmission for a period of time.

[0156] CSR can be derived from, for example Figure 9The APs 901-1 and 902-2 shown support one type of multi-AP coordination. Spatial reuse using CSR can be more stable than non-AP coordinated spatial reuse schemes such as Overlapping Basic Service Set (OBSS) Packet Detection-based (PD) SR and PSR-based SR. For example, in example network 900, APs 902-1 and 902-2 can perform joint probe operations to measure path loss (PL) on paths in network 900. For example, the joint probe operation might achieve the measurement of PL 908 for the path between APs 902-1 and 902-2, path loss 910 for the path between AP 902-1 and STA 904-2, and path loss 912 for the path between AP 902-2 and STA 904-1. The measured path loss information can then be shared between APs 902-1 and 902-2 (e.g., using backhaul) to allow APs 902-1 and 902-2 to transmit simultaneously to their associated STAs 904-1 and 904-2, respectively. Specifically, one of APs 902-1 and 902-2 acquires a TXOP to become the master AP. The master AP can then send CSR advertisement frames to the other APs. In an embodiment, the master AP may perform a polling operation before sending the CSR advertisement frame to poll the slave APs regarding packet availability for transmission. If at least one slave AP responds indicating packet availability, the master AP can proceed to send the CSR advertisement frame. In the CSR advertisement, the master AP may limit the transmission power of the slave APs to protect its own transmission to its target STA. Similarly, the slave APs can protect their own transmission to their target STA by selecting a modulation scheme that achieves a sufficiently high signal-to-interference ratio (SIR) margin to support interference caused by transmissions from the master AP to its target STA.

[0157] Figure 10 Example 1000 illustrates a multi-AP operation flow. In Example 1000, the multi-AP operation flow is illustrated for a multi-AP network including APs 1002 and 1004, and STAs 1006 and 1008. In the example, APs 1002 and 1004 can form a multi-AP group. AP 1002 can be the master AP, and AP 1004 can be a slave AP. For example, AP 1002 can obtain a TXOP, making it the master AP of the multi-AP group. Alternatively, AP 1002 can be designated as the master AP by the multi-AP controller.

[0158] like Figure 10As shown, the multi-AP operation process may include a series of time phases, where each phase may include multiple frame exchanges within the multi-AP network. Specifically, the multi-AP operation process may include a multi-AP selection phase 1010, a multi-AP data sharing phase 1012, a multi-AP detection phase 1014, and a multi-AP data transmission phase 1016.

[0159] Multi-AP networks can perform multi-AP operations based on a specific multi-AP transmission scheme. The multi-AP transmission scheme can be selected by the master AP based on the capabilities of the slave APs in the multi-AP group. Before multi-AP operation, slave APs can notify the master AP of their associated capability information, including their ability to support one or more multi-AP transmission schemes. Slave APs can also notify the master AP of their BSS information and the link quality information of the STAs associated with them. The master AP can receive information related to all available slave APs. This information can include capability information, BSS information, and link quality information. Based on the information provided by the available slave APs, the master AP can determine, during the multi-AP selection phase, which slave APs will be designated for multi-AP transmission and the specific multi-AP transmission scheme to be used during the multi-AP transmission.

[0160] The multi-AP selection phase 1010 may include procedures for the master AP to request, select, or specify slave APs in a multi-AP group. For example... Figure 10 As shown, the multi-AP selection phase may include the transmission of frame 1018 from AP 1002 and frame 1020 from AP 1004. AP 1002 may transmit frame 1018 to request information about the buffer status of AP 1004. In response, AP 1004 may transmit frame 1020 to inform AP 1002 of its buffer status and / or whether it intends to join the multi-AP operation. The multi-AP selection phase 1010 may also be used to exchange information related to multi-AP operation, including, for example, the BSS information of the APs and the link quality information between each AP and its associated STAs. The BSS information of the APs may include the BSSID of the AP's BSS, the identifiers and / or capabilities of the STAs belonging to the BSS, information about the STAs' detection capabilities, information about the AP's MIMO capabilities, etc. The link quality information may include Received Signal Strength Indicator (RSSI), Signal-to-Noise Ratio (SNR), Signal-to-Interference-plus-Noise Ratio (SINR), Channel State Information (CSI), and Channel Quality Indicator (CQI).

[0161] Multi-AP data sharing phase 1012 may include a process for sharing data frames to be transmitted between the master AP and selected slave APs via direct connections between APs to the associated STA. Phase 1012 may be optional for some multi-AP data transmission schemes. For example, JT / JR may require phase 1012 because data frames can be exchanged between APs before or after multi-AP data transmission phase 1016.

[0162] The multi-AP data sharing phase 1012 can be performed using wired backhaul, in-channel wireless backhaul, or out-of-channel wireless backhaul. In some cases, the multi-AP data sharing phase 1012 can be performed on in-channel backhaul, for example, using the same wireless channel used to transmit / receive data to / from the STA. For example, as... Figure 10 As shown, in stage 1012, AP 1002 can transmit frame 1022, which can be received by AP 1004. Frame 1022 may include an MPDU that AP 1002 wishes to transmit to an associated STA using multi-AP operation. Similarly, AP 1004 can transmit frame 1024, which can be received by AP 1002. Frame 1024 may include an MPDU that AP 1004 wishes to transmit to an associated STA using multi-AP operation.

[0163] Multi-AP probing phase 1014 may include procedures for multi-AP channel probing, including channel estimation and feedback of channel estimates between the master AP, candidate slave APs, and associated STAs. Phase 1014 may be optional for some multi-AP transport schemes (such as COFDMA, CDTMA, and CSR). For example, phase 1014 may be performed by the master AP to assist in resource unit allocation when orchestrating COFDMA transports.

[0164] Multi-AP data transmission phase 1016 may include exchanging data frames between the master AP, slave APs, and their associated STAs based on a multi-AP transmission scheme determined by the master AP. Depending on the multi-AP transmission scheme to be used, phase 1016 may include optional synchronization between APs in the multi-AP group before exchanging data frames between APs and STAs within the multi-AP group.

[0165] The order of stages 1010, 1012, 1014, and 1016 can be compared with... Figure 10 The differences are illustrated. For example, in COFDMA, stage 1016 may occur immediately after stage 1010, while in JT / JR, stage 1012 may occur after stage 1010. Furthermore, as mentioned above, some stages may be optional and may or may not be present. For example, stage 1014 may not be required for COFDMA but may be required for JT / JR.

[0166] Figure 11 The illustration shows an example 1100 of a multi-AP detection phase. Multi-AP detection phase 1100 can be an example of multi-AP detection phase 1014. For example... Figure 11 As shown, Example 1100 may include a master AP 1102 and a slave AP 1104 in a multi-AP group. Example 1100 may also include a STA 1106 associated with AP 1102 and a STA 1108 associated with AP 1104.

[0167] like Figure 11 As shown, the multi-AP detection phase 1100 may include frame switching to allow AP 1102 (the master AP) to acquire channel state information (CSI) of the channels in the multi-AP group. In an implementation, phase 1100 may include a first sub-phase 1110 and a second sub-phase 1112.

[0168] During the first sub-phase 1110, the AP can initiate channel sensing, and the STA can estimate the CSI. For example, AP 1102 can transmit frame 1114 to AP 1104 (from the AP) to trigger multi-AP sensing. Frame 1114 may include a multi-AP trigger frame. Subsequently, APs 1102 and 1104 can transmit advertisement frames 1116-1 and 1116-2 to their respective associated STAs 1106 and 1108 to announce the transmission of the sensing frames. Frames 1116-1 and 1116-2 may include multi-AP null data PPDU advertisement (NDPA) frames. Frames 1116-1 and 1116-2 may be transmitted simultaneously. Next, APs 1102 and 1104 can transmit frames 1118-1 and 1118-2 to STAs 1106 and 1108, respectively. Frames 1118-1 and 1118-2 may include multi-AP null data PPDU (NDP) frames. STAs 1106 and 1108 receive frames 1118-1 and 1118-2 respectively, and perform channel estimation for the channels from AP 1102 to STA 1106 and from AP 1104 to STA 1108 respectively.

[0169] During the second sub-phase 1112, the AP can initiate a process for STAs to feed back channel estimates to the AP. For example, AP 1102 can transmit frame 1120 to trigger STAs 1106 and 1108 to transmit their channel estimates to APs 1102 and 1104, respectively. Frame 1120 may include a multi-AP trigger frame. In response, STAs 1106 and 1108 can transmit frames 1122 and 1124, respectively, to APs 1102 and 1104, including feedback on the channel estimates. Frames 1122 and 1124 may include NDP feedback frames. The feedback on the channel estimates may include NDP feedback, CSI-related information, beamforming report (BFR), or channel quality indication (CQI) report.

[0170] Figure 12 The illustration shows an example 1200 of the multi-AP downlink data transmission phase. The multi-AP downlink data transmission phase 1200 can be an example of the multi-AP data transmission phase 1016. For example... Figure 12 As shown, Example 1200 may include a master AP 1202 and a slave AP 1204 in a multi-AP group. Example 1200 may also include a STA 1206 associated with AP 1202 and a STA 1208 associated with AP 1204.

[0171] like Figure 12 As shown, the multi-AP downlink data transmission phase 1200 may include frame switching to enable the master AP 1202 to coordinate with the slave AP 1204 to execute a specific multi-AP transmission scheme with its associated STAs 1206 and 1208, respectively. The multi-AP transmission scheme may include COFDMA, CTDMA, CSR, CBF, JT / JR, or a combination of two or more of the above schemes.

[0172] like Figure 12 As shown, the master AP 1202 can initiate phase 1200 by transmitting frame 1210 to AP 1204. Frame 1210 may include information related to AP 1204 (e.g., an identifier for AP 1204), synchronization information, information related to a specific multi-AP transmission scheme to be used, and / or information related to resource elements (RUs) used by AP 1204 to acknowledge frame 1210. Frame 1210 may include a control frame. For example, frame 1210 may include a multi-AP trigger frame.

[0173] AP 1204 can receive frame 1210 and can use synchronization information to synchronize with the master AP 1202. Subsequently, APs 1202 and 1204 can respectively perform data transmissions to their associated STAs 1206 and 1208. Specifically, AP 1202 can transmit data frame 1212 to its associated STA 1206, and AP 1204 can transmit data frame 1214 to its associated STA 1208. Depending on the multi-AP transmission scheme used, APs 1202 and 1204 can respectively transmit frames 1212 and 1214 to STAs in different BSSs. For example, when the multi-AP transmission scheme is JT / JR, AP 1202 can also transmit frame 1212 to STA 1208 associated with AP 1204, and AP 1204 can also transmit frame 1214 to STA 1208 associated with AP 1204. The resources used to transmit and receive frames 1212 and 1214 can depend on the specific multi-AP transmission scheme employed.

[0174] STAs 1206 and 1208 can acknowledge frames 1212 and 1214, respectively. For example, STA 1206 can transmit frame 1216 to AP 1202, and STA 1208 can transmit frame 1218 to AP 1204. Frames 1216 and 1218 may include block Ack (BA) frames. When required by the multi-AP transmission scheme used, STAs 1206 and 1208 can also transmit frames 1216 and 1218 to APs in different BSSs. For example, when the multi-AP transmission scheme is JT / JR, STA 1206 can also transmit frame 1216 to AP 1204, and STA 1208 can also transmit frame 1218 to AP 1202. The resources used for transmitting and receiving frames 1216 and 1218 may depend on the specific multi-AP transmission scheme employed.

[0175] Figure 13 The illustration shows an example 1300 of the multi-AP uplink data transmission phase. The multi-AP uplink data transmission phase 1300 can be an example of the multi-AP data transmission phase 1016. For example... Figure 13 As shown, Example 1300 may include a master AP 1302 and a slave AP 1304 in a multi-AP group. Example 1300 may also include STAs 1306 and 1308 associated with AP 1302, and STA 1310 associated with AP 1304.

[0176] like Figure 13 As shown, the multi-AP uplink data transmission phase 1300 may include frame switching to enable the master AP 1302 to coordinate with the slave AP 1304 to execute a specific multi-AP transmission scheme with STAs 1306, 1308, and 1310. The multi-AP transmission scheme may include COFDMA, CTDMA, CSR, CBF, JT / JR, or a combination of two or more of the above schemes.

[0177] like Figure 13 As shown, the master AP 1302 can initiate phase 1300 by transmitting frame 1312 to AP 1304. Frame 1312 may include information related to AP 1304 (e.g., an identifier for AP 1304), synchronization information, information related to a specific multi-AP transmission scheme to be used, and / or information related to the RU used by AP 1304 to acknowledge frame 1312. Frame 1312 may include a control frame. For example, frame 1312 may include a multi-AP trigger frame.

[0178] AP 1304 can receive frame 1312 and can use synchronization information to synchronize with the master AP 1302. Subsequently, APs 1302 and 1304 can use trigger frames to request uplink data transmissions from their associated STAs 1306, 1308, and 1310. Specifically, AP 1302 can transmit trigger frame 1314 to its associated STAs 1306 and 1308, and AP 1304 can transmit trigger frame 1316 to its associated STA 1310. Depending on the multi-AP transmission scheme used, APs 1302 and 1304 can also transmit frames 1314 and 1316 to STAs in different BSSs, respectively. For example, when the multi-AP transmission scheme is JT / JR, AP 1302 can also transmit frame 1314 to STA 1310 associated with AP 1304, and AP 1304 can also transmit frame 1316 to STAs 1306 and 1308 associated with AP 1302. The resources used for transmitting and receiving frames 1314 and 1316 may depend on the specific multi-AP transmission scheme employed.

[0179] STAs 1306 and 1308 can respond to frame 1314, and STA 1310 can respond to frame 1316. For example, STAs 1306 and 1308 can transmit frames 1318 and 1320 to AP 1302, respectively, while STA 1310 can transmit frame 1322 to AP 1304. Frames 1318, 1320, and / or 1322 can be transmitted simultaneously. Frames 1318, 1320, and 1322 may include data frames or empty data frames. When required by the multi-AP transmission scheme used, STAs 1306, 1308, and 1310 can also transmit frames 1318, 1320, and 1322 to APs in different BSSs, respectively. For example, when the multi-AP transmission scheme is JT / JR, STAs 1306 and 1308 can also transmit frames 1318 and 1320 to AP 1304, and STA 1310 can also transmit frame 1322 to AP 1302. The resources used for transmitting and receiving frames 1318, 1320, and 1322 can depend on the specific multi-AP transmission scheme employed. AP 1302 can acknowledge frames 1318 and 1320 by transmitting a multi-STA BA frame 1324 to STAs 1306 and 1308. AP 1304 can acknowledge frame 1322 by transmitting a BA frame 1326 to STA 1310.

[0180] Figure 14The diagram illustrates Enhanced Distributed Channel Access (EDCA) and Coordinated Time Division Multiple Access (CTDMA). In CTDMA, an AP (often called the master AP or sharing AP) can share a portion of its TXOP with one or more APs (often called slave APs or shared APs). Specifically, the sharing AP can assign / allocate a corresponding time slot within its TXOP for each of the one or more APs. The shared AP can use its assigned time slot to communicate with one or more STAs. Compared to Enhanced Distributed Channel Access (EDCA), CTDMA... Figure 14 The example shown is a multi-AP channel access scheme. Figure 14 As shown, in EDCA, channel access by multiple APs (e.g., AP1, AP2) can occur within consecutive time periods (e.g., TXOPs), where each AP has its own TXOP. During a given channel access period, a single AP can use its entire channel for the duration of the TXOP. Conversely, in CTDMA, access by multiple APs can occur within the same TXOP within consecutive time periods. For example, as... Figure 14 As shown, a TXOP can be divided into two non-overlapping time slots, each assigned to a corresponding AP among multiple APs. Multiple APs can transmit consecutively in a coordinated manner within the same TXOP. In the example, as... Figure 14 As shown, a primary / shared AP (e.g., AP1) can use itself as the first part of a first TXOP and can share the second part of the first TXOP with a secondary / shared AP (e.g., AP2). In another example, a primary / shared AP (e.g., AP1) can share the first part of a second TXOP with a secondary / shared AP (e.g., AP2) and can use itself as the second part of the second TXOP.

[0181] Triggered TXOP Sharing (TXS) is a technology introduced in the IEEE 802.11be standard modification. TXS allows an AP to allocate the duration within a acquired TXOP to a STA for sending one or more non-triggered (non-TB) PPDUs. For the TXS procedure, the AP can transmit a Multi-User Request to Send (MU-RTS) trigger frame with the Triggered TXOP Sharing Mode subfield set to a non-zero value. The MU-RTS trigger frame is used to trigger CTS frames from multiple users. An MU-RTS trigger frame with the Triggered TXOP Sharing Mode subfield set to a non-zero value is called a MU-RTS TXS Trigger (MRTT) frame.

[0182] In the example, when the triggered TXOP sharing 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 triggered TXOP sharing mode subfield is set to 2, the STA can transmit one or more non-TB PPDUs to the AP or a peer STA during the allocated duration. A peer STA can be a STA with a connection for peer-to-peer (P2P) communication or direct communication with another STA. In the example, a direct wireless link is established according to the Tunnel Direct Link Establishment (TDLS) protocol.

[0183] Figure 15 The illustration shows an example of an MRTT frame 1500 that can be used in the TXS process. For example... Figure 15 As shown, the example MRTT frame 1500 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.

[0184] 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 15 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 / triggered TXOP sharing mode, number of HE / EHT-LTF symbols, LDPC additional symbol fragments, AP Tx power, pre-FEC fill factor, PE disambiguation, UL space reuse, HE / EHT P160, special user information field flag, EHT reservation, reservation, or trigger-related public information.

[0185] The trigger type subfield indicates that frame 600 is an MRTT frame.

[0186] The GI and HE / EHT-LTF type / triggered TXOP sharing mode subfield can include a triggered TXOP sharing mode subfield. In the example, the triggered TXOP sharing mode subfield can be set to a non-zero value (e.g., 1 or 2). In the example, the triggered TXOP sharing mode subfield can be set to 1. This allows the triggered TXOP sharing mode subfield to 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 in the Allocation Duration subfield of the User Information field. In another example, the triggered TXOP sharing mode subfield can be set to 2. This allows the triggered TXOP sharing mode subfield to 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 peer STA during the time period indicated in the Allocation Duration subfield of the User Information field. In the example, the peer STA can be a STA with a connection for P2P or direct communication with the STA.

[0187] The user information list fields can include one or more user information fields. In the example, such as... Figure 15 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.

[0188] The AID12 subfield can indicate the associated identifier (AID) of the STA that can use the time indicated by the Assigned Duration subfield.

[0189] The RU allocation subfield can indicate the location and size of the RU allocated to the STA as indicated by the AID12 subfield.

[0190] The allocation duration subfield can indicate the time allocated by the AP transmitting MRTT frame 1500. The allocated 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.

[0191] Figure 16 Example 1600 illustrates the TXS process (mode=1). Figure 16As shown, the TXS procedure can begin when AP1610 transmits MRTT frame 1620 to STA 1611. MRTT frame 1620 may allocate a portion of the TXOP obtained by AP 1610 to STA 1611 and may indicate a TXS mode equal to 1. STA 1611, receiving MRTT frame 1620, can use the allocated time to transmit one or more non-TB PPDUs to AP 1610. The one or more non-TB PPDUs may include data frames, control frames, management frames, or action frames.

[0192] In the example, MRTT frame 1620 may include a triggered TXOP shared mode subfield indicating TXS mode and / or a subfield indicating 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).

[0193] STA 1611 can respond to MRTT frame 1620 by transmitting CTS frame 1621 to AP 1610. Subsequently, STA 1611 can transmit non-TB PPDUs 1622, 1624, including one or more data frames, to AP 1610 during a first time period indicated in MRTT frame 1620. In the example, AP 1610 can transmit one or more block Ack(BA) frames 1623, 1625 in response to one or more data frames contained in the non-TB PPDUs 1622, 1624 received from STA 1611.

[0194] Figure 17 Example 1700 illustrates the TXS process (mode=2). For example... Figure 17 As shown, the TXS procedure can begin with AP1710 transmitting MRTT frame 1720 to STA 1711. MRTT frame 1720 may allocate a portion of the TXOP obtained by AP 1710 to STA 1711 and may indicate a TXS mode equal to 2. STA 1711, receiving MRTT frame 1720, can use the allocated time to transmit one or more non-TB PPDUs to STA 1712. The one or more non-TB PPDUs may include data frames, control frames, management frames, or action frames.

[0195] In the example, MRTT frame 1720 may include a triggered TXOP shared mode subfield indicating TXS mode and / or a subfield indicating a first time period corresponding to the allocated time. In the example, the first time period may be set to a value of Y microseconds (µs).

[0196] STA 1711 can respond to MRTT frame 1720 by transmitting CTS frame 1721 to AP 1710. Subsequently, STA 1711 can transmit non-TB PPDUs 1722, 1724, including one or more data frames, to STA 1712 during the first time period indicated in MRTT frame 1720. In the example, STA 1712 can transmit one or more BA frames 1723, 1725 in response to one or more data frames contained in the non-TB PPDUs 1722, 1724 received from STA 1711.

[0197] In CTDMA, a method for TXOP sharing can be implemented via the aforementioned TXS procedure. The TXS procedure can be used to allow a sharing AP that acquires and owns a TXOP to allocate the duration within its acquired TXOP to a shared AP for downlink and / or uplink transmissions between the shared AP and its associated STA.

[0198] Figure 18 The illustration shows an example 1800 of an existing CTDMA procedure. Figure 18 As shown, Example 1800 may include APs 1802 and 1804, and STAs 1806 and 1808. APs 1802 and 1804 may be members of a multi-AP group. AP 1802 may be the shared / master AP of the multi-AP group. AP 1804 may be the shared / slave AP of the multi-AP group. STA 1806 may be associated with AP 1802, and STA 1808 may be associated with AP 1804. In Example 1800, it is assumed that APs 1802, 1804 and STAs 1806, 1808 are within each other's communication range.

[0199] In implementations, an AP (such as AP 1802 and 1804) or STA (such as STA 1806 and 1808) can maintain two NAVs: an intra-BSS NAV and a basic NAV. The intra-BSS NAV is updated (set or reset) based on intra-BSS PPDUs (i.e., PPDUs received from the BSS to which the STA / AP belongs). The basic NAV is updated (set or reset) based on inter-BSS PPDUs (i.e., PPDUs received from a BSS different from the BSS to which the STA / AP belongs (also called inter-BSS or OBSS)) or PPDUs that cannot be classified as intra-BSS or inter-BSS.

[0200] For STAs using the EDCA access channel, both NAVs must be non-zero. The STA's basic NAV is not updated by transmissions from the AP associated with the STA, such that if the STA's basic NAV is non-zero and the STA receives a trigger frame from the AP with the CS demand subfield equal to 1, the STA does not respond. The STA does not consider the BSS-internal NAV when determining whether to respond to a trigger frame sent by the AP associated with the STA. The STA considers the basic NAV when determining whether to respond to a trigger frame sent by the AP associated with the STA.

[0201] like Figure 18 As shown, the process can begin with AP 1802 transmitting MRTT frame 1812 after acquiring TXOP 1810. In an implementation, MRTT frame 1812 may include an allocation for AP 1804. The allocation of MRTT frame 1812 may include the identifier of the shared AP and the duration allocated to the shared AP (within the TXOP). In example 1800, MRTT frame 1812 may include an allocation for AP 1804. This allocation may include a first duration of the TXOP allocated to AP 1804 (within the TXOP). Figure 18 (represented as t1). The first duration can be indicated in the allocation duration subfield of the user information list field in MRTT frame 1812. In an implementation, the duration field of MRTT frame 1812 can indicate a second duration (in...). Figure 18 (represented as t2). The second duration indicated in the duration field of MRTT frame 1812 can be shorter than the first duration. This is to avoid causing the associated STA of the shared AP, which is the OBSS STA of the shared AP, to set its basic NAV for a long duration (e.g., the first duration) after receiving the MRTT frame, which would result in the associated STA not responding to trigger frames from its associated shared AP, which has TXOP during the first duration. In the implementation, setting the duration field of MRTT frame 1812 to the second duration allows AP 1802 to protect the CTS frames and / or trigger frames of the shared AP.

[0202] In Example 1800, upon receiving MRTT frame 1812, STA 1806 can set its BSS-internal NAV ( Figure 18 (not shown) is set to the second duration t2 indicated in MRTT frame 1812. Upon receiving MRTT frame 1812, STA 1808 can set its basic NAV ( Figure 18(Not shown) is set to the second duration t2. Upon receiving MRTT frame 1812, AP 1804 can determine that AP 1802 has shared TXOP 1810 with AP 1804 for duration t1. AP 1804 can then transmit CTS frame 1814 to AP 1802 in response to MRTT frame 1812.

[0203] When receiving CTS frame 1814, AP 1802 can set its BSS-in-NAV (Navigate to Virtual Object) for the remaining duration t2. Figure 18 (Not shown in the image). After transmitting CTS frame 1814, AP 1804 can use TXOP for the remaining duration of t1. In the example, AP 1804 can transmit downlink frames to STA 1808 (…). Figure 18 (Not shown in the image). In another example, AP 1804 can trigger STA 1808 to send an uplink frame to AP 1804.

[0204] In Example 1800, after transmitting CTS frame 1814, AP 1804 can transmit trigger frame 1816 to STA 1808 to trigger uplink transmission from STA 1808. In this implementation, the duration field of trigger frame 1816 can indicate a third duration t3. Upon receiving trigger frame 1816, OBSS AP or OBSS STA can set its basic NAV based on the duration field of trigger frame 1816. Specifically, in Example 1800, upon receiving trigger frame 1816, AP 1802 can set its basic NAV ( Figure 18 (Not shown in the image) is set to the third duration indicated in trigger frame 1816. Similarly, upon receiving trigger frame 1816, STA 1806 can set its basic NAV (such as...) to the third duration indicated in trigger frame 1816. Figure 18 The NAV (shown in 1818) is set to the third duration indicated in trigger frame 1816.

[0205] In this implementation, upon receiving trigger frame 1816 and seeing its own address in the RA field of trigger frame 1816, STA 1808 can determine that it wants to transmit an uplink frame to AP 1804. In this implementation, when trigger frame 1816 is transmitted by AP 1804 associated with STA 1808, STA 1808 can set its NAV (Network Address Access Entity) within its BSS. Figure 18(Not shown) is set to the third duration indicated in trigger frame 1816. In another embodiment, STA 1808 may not set its NAV within its BSS. Subsequently, STA 1808 may transmit data frame 1820 to AP 1804. Data frame 1820 may include a duration field indicating the remaining duration of the third duration. In response to data frame 1820, AP 1804 may transmit BA frame 1822 to STA 1808.

[0206] In the example, after transmitting BA frame 1822 to STA 1808, AP 1804 may not have any further uplink and / or downlink transmissions to perform during the remainder of the first duration allocated to AP 1804. In an implementation, AP 1804 may return the remainder of the first duration to AP 1802 (also referred to as truncating the first duration). In example 1800, AP 1804 may transmit frame 1824 indicating that AP 1804 returns the first duration to AP 1802 (or indicating that AP 1804 truncates the first duration). In the example, frame 1824 may be a contention-free end (CF-end) frame. In the example, the CF-end frame may include an indication of the transmitter address (TA) of AP 1804. In the example, the CF-end frame may be a broadcast frame.

[0207] In Example 1800, upon receiving CF-end frame 1824, AP 1802 can reset its basic NAV to zero before the end of the third duration. AP 1802 can also determine that AP 1804 has returned the first duration to AP 1802. With the first duration returned to AP 1802, AP 1802 (which is the owner of the TXOP) returns to being the holder of the TXOP. Similarly, upon receiving CF-end frame 1824, STA 1806 can reset its basic NAV (as shown in the image) before the end of the third duration. Figure 18 (As shown). Upon receiving CF-end frame 1834, STA 1808 can reset its intra-BSS NAV before the end of the third duration.

[0208] In the example, as the first duration returns to AP 1802, AP 1802 can initiate uplink and / or downlink transmissions during the remaining duration of TXOP 1810 (which includes the remainder of the first duration). In the example, AP 1802 can transmit frame 1826 to STA 1806 to initiate an uplink transmission. In the example, frame 1826 can be a trigger frame. Upon receiving frame 1826, the OBSS AP or OBSS STA can set its basic NAV. Thus, AP 1804 can set its basic NAV ( Figure 18(Not shown in the image) is set to the duration indicated in frame 1826. Similarly, STA 1808 can set its basic NAV ( Figure 18 (Not shown in the image) is set to the duration indicated in frame 1826.

[0209] Upon receiving frame 1826 and seeing its own address in the RA field of frame 1826, STA 1806 can determine that it will transmit an uplink frame to AP 1802. STA 1806 can then set its NAV (Network Address) within its BSS. Figure 18 (Not shown in the image) is set to the duration indicated in frame 1826. In another embodiment, STA 1806 may not set its NAV within its BSS. In response to frame 1826, STA 1806 may transmit frame 1828 to AP 1802. In this example, frame 1828 may be a data frame. In this embodiment, frame 1828 may include a duration field indicating the remaining portion of frame 1826, which indicates the duration. In this example, after receiving frame 1828, AP 1802 may transmit a BA frame (not shown in the image) to STA 1806. Figure 18 (Not shown in the image), and uplink and / or downlink transmissions can continue within TXOP 1810. In another example, AP 1802 can share the remainder of TXOP1810 with another shared AP.

[0210] Figure 19 Another example of an existing CTDMA procedure is illustrated in Figure 1900. Figure 19 As shown, Example 1900 may include APs 1902 and 1904, and STAs 1906 and 1908. APs 1902 and 1904 may be members of a multi-AP group. AP 1902 may be the shared / master AP of the multi-AP group. AP 1904 may be the shared / slave AP of the multi-AP group. STA 1906 may be associated with AP 1902, and STA 1908 may be associated with AP 1904. In Example 1900, it is assumed that APs 1902, 1904, and STA 1908 are within each other's communication range. It is further assumed that STA 1906 is outside the communication range of AP 1904, but within the communication range of APs 1902 and STA 1908.

[0211] like Figure 19As shown, the process can begin with AP 1902 transmitting MRTT frame 1912 after acquiring TXOP 1910. In one implementation, MRTT frame 1912 may include an allocation for AP 1904. The allocation of MRTT frame 1912 may include the identifier of the shared AP and the duration allocated to the shared AP (within the TXOP). In example 1900, MRTT frame 1912 may include an allocation for AP 1904. This allocation may include a first duration of the TXOP allocated to AP 1904 (within the TXOP). Figure 19 (represented as t1). The first duration can be indicated in the allocation duration subfield of the user information list field in MRTT frame 1912. In an implementation, the duration field of MRTT frame 1912 can indicate a second duration (in...). Figure 19 (represented as t2). The second duration indicated in the duration field of MRTT frame 1912 can be shorter than the first duration. This is to avoid causing the associated STA of the shared AP, which is the OBSS STA of the shared AP, to set its basic NAV for a long duration (e.g., the first duration) after receiving the MRTT frame, which would result in the associated STA not responding to trigger frames from its associated shared AP, which has TXOP during the first duration. In the implementation, setting the duration field of MRTT frame 1912 to the second duration allows AP 1902 to protect the CTS frames and / or trigger frames of the shared AP.

[0212] In Example 1900, upon receiving MRTT frame 1912, STA 1906 can set its BSS-internal NAV ( Figure 19 (not shown in the image) is set to the second duration t2 indicated in MRTT frame 1912. Upon receiving MRTT frame 1912, STA 1908 can set its basic NAV (... Figure 19 (Not shown in the image) is set to the second duration t2. Upon receiving MRTT frame 1912, AP 1904 can determine that AP 1902 has shared TXOP 1910 with AP 1904 for duration t1. AP 1904 can then transmit CTS frame 1914 to AP 1902 in response to MRTT frame 1912.

[0213] When receiving CTS frame 1914, AP 1902 can set its intra-BSV (NAV) for the remaining duration t2. Figure 19 (Not shown in the image). After transmitting CTS frame 1914, AP 1904 can use TXOP for the remaining duration of t1. In the example, AP 1904 can transmit downlink frames to STA 1908 (…). Figure 19(Not shown in the image). In another example, AP 1904 can trigger STA 1908 to send an uplink frame to AP 1904.

[0214] In Example 1900, after transmitting CTS frame 1914, AP 1904 can transmit trigger frame 1916 to STA 1908 to trigger an uplink transmission from STA 1908. In this implementation, the duration field of trigger frame 1916 can indicate a third duration t3. Upon receiving trigger frame 1916, the OBSS AP or OBSS STA can set its basic NAV based on the duration field of trigger frame 1916. Specifically, in Example 1900, upon receiving trigger frame 1916, AP 1902 can set its basic NAV ( Figure 19 (Not shown) is set to the third duration indicated in trigger frame 1916. However, outside the communication range of AP 1904, STA 1906 may not receive trigger frame 1916 and may not set its basic NAV.

[0215] In this implementation, upon receiving trigger frame 1916 and seeing its own address in the RA field of trigger frame 1916, STA 1908 can determine that it wants to transmit an uplink frame to AP 1904. In this implementation, when trigger frame 1916 is transmitted by AP 1904 associated with STA 1908, STA 1908 can set its BSS NAV (Network Address Access Parameter) to its own address. Figure 19 (Not shown in the image) is set to the third duration indicated in trigger frame 1916. In another embodiment, STA 1908 may not set its in-BSS NAV. Subsequently, STA 1908 may transmit data frame 1918 to AP 1904. Data frame 1918 may include a duration field indicating the remaining duration of the third duration. Upon receiving data frame 1918, STA 1906 may read the duration field of data frame 1918 and may set its basic NAV (e.g., ...) for the remaining duration of the third duration. Figure 19 (As shown in NAV 1920). In response to data frame 1918, AP 1904 can transmit BA frame 1922 to STA 1908.

[0216] In the example, after transmitting BA frame 1922 to STA 1908, AP 1904 may not have any further uplink and / or downlink transmissions to perform during the remainder of the first duration allocated to AP 1904. In an implementation, AP 1904 may return the remainder of the first duration to AP 1902 (also referred to as truncating the first duration). In example 1900, AP 1904 may transmit frame 1924 indicating that AP 1904 returns the first duration to AP 1902 (or indicating that AP 1904 truncates the first duration). In the example, frame 1924 may be a contention-free end (CF-end) frame. In the example, the CF-end frame may include an indication of the transmitter address (TA) of AP 1904. In the example, the CF-end frame may be a broadcast frame.

[0217] In Example 1900, upon receiving CF-end frame 1924, AP 1902 can reset its basic NAV to zero before the end of the third duration. AP 1902 can also determine that AP 1904 has returned the first duration to AP 1902. With the first duration returned to AP 1902, AP 1902 (which is the owner of the TXOP) reverts to being the holder of the TXOP. Outside the communication range of AP1904, STA 1906 may not receive CF-end frame 1924 and may not reset its basic NAV, which was set upon receiving data frame 1918 transmitted by STA 1908. Upon receiving CF-end frame 1924, STA 1908 can reset its intra-BSV before the end of the third duration.

[0218] In the example, as the first duration returns to AP 1902, AP 1902 can initiate uplink and / or downlink transmissions for the remaining duration of TXOP 1910 (which includes the remainder of the first duration). In the example, AP 1902 can transmit frame 1926 to STA 1906 to initiate an uplink transmission. In the example, frame 1926 can be a trigger frame. Upon receiving frame 1926, the OBSS AP or OBSS STA can set its basic NAV. Thus, AP 1904 can set its basic NAV ( Figure 19 (Not shown in the image) is set to the duration indicated in frame 1926. Similarly, STA 1908 can set its basic NAV ( Figure 19 (Not shown in the image) is set to the duration indicated in frame 1926.

[0219] In Example 1900, its basic NAV has already been set for the remainder of the third duration of received data frame 1918. Although frame 1926 is received and its own address is seen in the RA field of frame 1926, STA 1906 cannot respond to frame 1926 transmitted by AP 1902 according to the existing IEEE 802.11 standard. In an implementation, STA 1906 can set its NAV within its BSS (… Figure 19 (Not shown in the image) is set to the duration indicated in frame 1926. In another embodiment, STA 1906 may not have its NAV set within its BSS.

[0220] Therefore, STA 1906 may not transmit any uplink frames to AP 1902 until its basic NAV reaches zero or is reset. In other words, although AP 1904 has returned a TXOP to AP 1902 before the end of the first duration (t1) by transmitting CF-end frame 1924, STA 1906 associated with AP 1902 may be prevented from using the channel to transmit uplink frames to AP 1902 for the remainder of the first duration. This could result in unfair channel access between STAs associated with AP 1902 within AP 1902's communication range and STAs associated with AP 1902 outside AP 1902's communication range.

[0221] Figure 20 Another example of the CTDMA process (2000) is illustrated. Figure 20 As shown, Example 2000 may include APs 2002 and 2004, and STAs 2006 and 2008. APs 2002 and 2004 may be members of a multi-AP group. AP 2002 may be the shared / master AP of the multi-AP group. AP 2004 may be the shared / slave AP of the multi-AP group. STA 2006 may be associated with AP 2002, and STA 2008 may be associated with AP 2004. In Example 2000, it is assumed that APs 2002, 2004, and STA 2008 are within each other's communication range. It is further assumed that STA 2006 is outside the communication range of AP 2004, but within the communication range of APs 2002 and STA 2008.

[0222] like Figure 20As shown, the process can begin with AP 2002 transmitting MRTT frame 2012 after acquiring TXOP 2010. In an implementation, MRTT frame 2012 may include an allocation for AP 2004. The allocation of MRTT frame 2012 may include the identifier of the shared AP and the duration allocated to the shared AP (within the TXOP). In example 2000, MRTT frame 2012 may include an allocation for AP 2004. This allocation may include a first duration of the TXOP allocated to AP 2004 (within the TXOP). Figure 20 (represented as t1). The first duration can be indicated in the allocation duration subfield of the user information list field in the MRTT frame 2012. In an implementation, the duration field of the MRTT frame 2012 can indicate a second duration (in...). Figure 20 (represented as t2). The second duration indicated in the duration field of the MRTT frame 2012 can be shorter than the first duration. This is to avoid causing the associated STA of the shared AP, which is the OBSS STA of the shared AP, to set its basic NAV for a long duration (e.g., the first duration) after receiving the MRTT frame, which would result in the associated STA not responding to trigger frames from its associated shared AP, which has TXOP during the first duration. In the implementation, setting the duration field of the MRTT frame 2012 to the second duration allows AP 2002 to protect the CTS frames and / or trigger frames of the shared AP.

[0223] In Example 2000, upon receiving MRTT frame 2012, STA 2006 can set its BSS-internal NAV ( Figure 20 (not shown) is set to the second duration t2 indicated in MRTT frame 2012. Upon receiving MRTT frame 2012, STA 2008 can set its basic NAV ( Figure 20 (Not shown) is set to the second duration t2. Upon receiving MRTT frame 2012, AP 2004 can determine that AP 2002 has shared TXOP 2010 with AP 2004 for duration t1. AP 2004 can then transmit CTS frame 2014 to AP 2002 in response to MRTT frame 2012.

[0224] When receiving CTS frame 2014, AP 2002 can set its BSS-internal NAV (Navigate to Virtual Object) within the remaining duration t2. Figure 20 (Not shown in the image). After transmitting CTS frame 2014, AP 2004 can use TXOP for the remaining duration of t1. In the example, AP 2004 can transmit downlink frames to STA 2008 (…). Figure 20(Not shown in the image). In another example, AP 2004 can trigger STA 2008 to send an uplink frame to AP 2004.

[0225] In Example 2000, after transmitting CTS frame 2014, AP 2004 can transmit trigger frame 2016 to STA 2008 to trigger uplink transmission from STA 2008. In this implementation, the duration field of trigger frame 2016 can indicate a third duration t3. Upon receiving trigger frame 2016, OBSS AP or OBSS STA can set its basic NAV based on the duration field of trigger frame 2016. Specifically, in Example 2000, upon receiving trigger frame 2016, AP 2002 can set its basic NAV ( Figure 20 (Not shown) is set to the third duration indicated in trigger frame 2016. However, outside the communication range of AP 2004, STA 2006 may not receive trigger frame 2016 and may not set its basic NAV.

[0226] In an implementation, upon receiving trigger frame 2016 and seeing its own address in the RA field of trigger frame 2016, STA 2008 can determine that it wants to transmit an uplink frame to AP 2004. In an implementation, when trigger frame 2016 is transmitted by AP 2004 associated with STA 2008, STA 2008 can set its BSS NAV (Network Address Access Parameter) to its own address. Figure 20 (Not shown in the image) is set to the third duration indicated in trigger frame 2016. In another embodiment, STA 2008 may not set its in-BSS NAV. Subsequently, STA 2008 may transmit data frame 2018 to AP 2004. Data frame 2018 may include a duration field indicating the remaining duration of the third duration. Upon receiving data frame 2018, STA 2006 may read the duration field of data frame 2018 and may set its basic NAV (e.g., ...) for the remaining duration of the third duration. Figure 20 (As shown in NAV 2020). In response to data frame 2018, AP 2004 can transmit BA frame 2022 to STA 2008.

[0227] In the example, after transmitting BA frame 2022 to STA 2008, AP 2004 may not have any further uplink and / or downlink transmissions to perform during the remainder of the first duration allocated to AP 2004. In an implementation, AP 2004 may return the remainder of the first duration to AP 2002 (also referred to as truncating the first duration). In example 2000, AP 2004 may transmit frame 2024 indicating that AP 2004 returns the first duration to AP 2002 (or indicating that AP 2004 truncates the first duration). In the example, frame 2024 may be a contention-free end (CF-end) frame. In the example, the CF-end frame may include an indication of the transmitter address (TA) of AP 2004. In the example, the CF-end frame may be a broadcast frame.

[0228] In Example 2000, upon receiving CF-end frame 2024, AP 2002 can reset its basic NAV to zero before the end of the third duration. AP 2002 can also determine that AP 2004 has returned the first duration to AP 2002. With the first duration returned to AP 2002, AP 2002 (which is the owner of the TXOP) reverts to being the holder of the TXOP. Outside the communication range of AP 2004, STA 2006 may not receive CF-end frame 2024 and may not reset its basic NAV, which was set upon receiving data frame 2018 transmitted by STA 2008. Upon receiving CF-end frame 2024, STA 2008 can reset its intra-BSV before the end of the third duration.

[0229] Because AP 2002 has the return duration of TXOP 2010, AP 2002 may want to initiate uplink and / or downlink transmissions for the remaining duration of TXOP 2010. If AP 2002 is to initiate an uplink transmission, AP 2002 may assess that its associated STAs that have not yet reset their basic NAV for the remaining duration of TXOP 2010 (e.g., due to not receiving the CF-end frame 2024 transmitted by AP 2004) may not respond to the trigger frame from AP 2002. AP 2002 may also assess that these associated STAs may have already set their basic NAV based on a frame received from an associated STA of AP 2004. This frame will have already been triggered by the trigger frame from AP 2004. Thus, in an implementation, after AP 2002 receives the trigger frame from AP 2004 and then AP 2004 transmits the CF-end frame, AP 2002 may transmit a frame to its associated STAs to reset their basic NAV.

[0230] In Example 2000, after receiving CF-end frame 2024, AP 2002 may transmit frame 2026 to STA 2006 for resetting STA 2006's basic NAV. In one implementation, frame 2026 may include a CF-end frame. In another implementation, the CF-end frame may include a transmitter address (TA) indicating the identifier of AP 2004 instead of the identifier of AP 2002. Thus, when STA 2006 receives frame 2026, STA 2006 can determine that frame 2026 is an inter-BSS PPDU. Therefore, STA 2006 can use frame 2026 to reset its basic NAV. In another implementation, frame 2026 may include a trigger frame, a Multi-User Request to Send Triggered TXOP Shared (MU-RTS TXS) Triggered (MRTT) frame, or a Request to Send (RTS) frame. In another implementation, the trigger frame, MRTT frame, or RTS frame may include a basic NAV reset indication. Even if the trigger frame, MRTT frame, or RTS frame is an in-BSS PPDU, the presence of a basic NAV reset indicator in the frame allows the STA to reset its basic NAV. In implementations, the basic NAV reset indicator may be provided in one of the reserved bits (e.g., B22, B26, B53, or B63) of the common information field of the trigger frame or MRTT frame, as shown in... Figure 5 and Figure 15 As illustrated in the diagram. In another implementation, the basic NAV reset indication can be provided in the frame control field of the RTS frame.

[0231] like Figure 20 As shown, upon receiving frame 2026, STA 2006 can reset its basic NAV before the end of the third duration (t3). After transmitting frame 2026, in the implementation, AP 2002 can transmit frame 2028 to STA 2006 to initiate an uplink transmission. In the example, frame 2028 can be a trigger frame. Upon receiving frame 2028, OBSS AP or OBSS STA can set its basic NAV. Thus, AP 2004 can set its basic NAV ( Figure 20 (Not shown in the image) is set to the duration indicated in frame 2028. Similarly, STA 2008 can set its basic NAV ( Figure 20 (Not shown in the image) is set to the duration indicated in frame 2028.

[0232] Upon receiving frame 2028 and seeing its own address in the RA field of frame 2028, STA 2006 can determine that it will transmit an uplink frame to AP 2002. STA 2006 can then set its NAV (Network Address) within its BSS. Figure 20(Not shown in the image) is set to the duration indicated in frame 2028. In another embodiment, STA 2006 may not set its NAV within its BSS. In response to frame 2028, STA 2006 may transmit frame 2030 to AP 2002. In the example, frame 2030 may be a data frame. In an embodiment, frame 2030 may include a duration field indicating the remaining portion of frame 2028 indicated by the duration. In the example, after receiving frame 2030, AP 2002 may transmit a BA frame (not shown in the image) to STA 2006. Figure 20 (Not shown in the image), and uplink and / or downlink transmissions can continue within TXOP 2010. In another example, AP 2002 can share the remainder of TXOP 2010 with another shared AP. As shown in Example 2000, if the shared AP has returned the TXOP to the sharing AP before the shared TXOP ends, a STA outside the communication range of the shared AP has successfully reset its basic NAV via receive frame 2026 for successful uplink transmission with its associated sharing AP.

[0233] Figure 21 Another example 2100 of the CTDMA process is illustrated. Figure 21 As shown, example 2100 may include APs 2102 and 2104, and STAs 2106, 2108, and 2109. APs 2102 and 2104 may be members of a multi-AP group. AP 2102 may be the sharing / master AP of the multi-AP group. AP 2104 may be a shared / slave AP of the multi-AP group. STA 2106 may be associated with AP 2102, and STA 2108 may be associated with AP 2104. STA 2109 may be associated with AP 2102 or with another AP other than AP 2104. Figure 21 (Not shown in the image) are associated. In Example 2100, it is assumed that APs 2102, 2104 and STA 2108 are within each other's communication range. It is further assumed that STA 2106 is outside the communication range of AP 2104, but within the communication range of AP 2102 and STA 2108. It is further assumed that STA 2109 is outside the communication range of AP 2104 and STA 2108, but within the communication range of AP 2102.

[0234] like Figure 21As shown, the process can begin with AP 2102 transmitting MRTT frame 2112 after acquiring TXOP 2110. In an implementation, MRTT frame 2112 may include an allocation for AP 2104. The allocation of MRTT frame 2112 may include the identifier of the shared AP and the duration allocated to the shared AP (within the TXOP). In example 2100, MRTT frame 2112 may include an allocation for AP 2104. This allocation may include a first duration of the TXOP allocated to AP 2104 (within the TXOP). Figure 21 (represented as t1). The first duration can be indicated in the allocation duration subfield of the user information list field of MRTT frame 2112. In the implementation, the duration is specified from an AP or STA other than AP 2102, AP 2104, STA 2106, or STA 2108. Figure 21 When receiving a frame (not shown in the image) (hereinafter referred to as other AP / STA), STA 2109 may have already set its basic NAV (such as...) before the transmission of MRTT frame 2112 and for a duration longer than the first duration. Figure 21 The NAV value 2111 in the image is shown. In an implementation, the duration field of the MRTT frame 2112 can indicate a second duration (in the image). Figure 21 (represented as t2). The second duration indicated in the duration field of MRTT frame 2112 may be shorter than the first duration. This is to avoid causing the associated STA of the shared AP, which is the OBSS STA of the shared AP, to set its basic NAV for a long duration (e.g., the first duration) after receiving the MRTT frame, which would result in the associated STA not responding to trigger frames from its associated shared AP, which has TXOP during the first duration. In the implementation, setting the duration field of MRTT frame 2112 to the second duration allows AP 2102 to protect the CTS frames and / or trigger frames of the shared AP.

[0235] In Example 2100, upon receiving MRTT frame 2112, STA 2106 can set its BSS-internal NAV ( Figure 21 (not shown in the image) is set to the second duration t2 indicated in MRTT frame 2112. Upon receiving MRTT frame 2112, STA 2108 can set its basic NAV (... Figure 21 (Not shown) is set to the second duration t2. Upon receiving MRTT frame 2112, AP 2104 can determine that AP 2102 has shared TXOP 2110 with AP 2104 for duration t1. AP 2104 can transmit CTS frame 2114 to AP 2102 in response to MRTT frame 2112.

[0236] When receiving CTS frame 2114, AP 2102 can set its BSS intra-NAV (Navigate to Virtual Object) for the remaining duration t2. Figure 21 (Not shown in the image). After transmitting CTS frame 2114, AP 2104 can use TXOP for the remaining duration of t1. In the example, AP 2104 can send a TXOP to STA 2108 (…). Figure 21 (Not shown in the image) transmits downlink frames. In another example, AP 2104 can trigger STA 2108 to transmit uplink frames to AP 2104.

[0237] In Example 2100, after transmitting CTS frame 2114, AP 2104 can transmit trigger frame 2116 to STA 2108 to trigger uplink transmission from STA 2108. In this implementation, the duration field of trigger frame 2116 may indicate a third duration t3. Upon receiving trigger frame 2116, OBSS AP or OBSS STA can set its basic NAV based on the duration field of trigger frame 2116. Specifically, in Example 2100, upon receiving trigger frame 2116, AP 2102 can set its basic NAV ( Figure 21 (Not shown) is set to the third duration indicated in trigger frame 2116. However, outside the communication range of AP 2104, STA 2106 may not receive trigger frame 2116 and may not set its basic NAV. Similarly, outside the communication range of AP 2104, STA 2109 may not receive trigger frame 2116 and may not update its basic NAV to the third duration indicated in trigger frame 2116.

[0238] In this implementation, upon receiving trigger frame 2116 and seeing its own address in the RA field of trigger frame 2116, STA 2108 can determine that it wants to transmit an uplink frame to AP 2104. In this implementation, when trigger frame 2116 is transmitted by AP 2104 associated with STA 2108, STA 2108 can set its NAV (Network Address Access Item) within its BSS. Figure 21 (Not shown in the image) is set to the third duration indicated in trigger frame 2116. In another embodiment, STA 2108 may not set its in-BSS NAV. Subsequently, STA 2108 may transmit data frame 2118 to AP 2104. Data frame 2118 may include a duration field indicating the remaining duration of the third duration. Upon receiving data frame 2118, STA 2106 may read the duration field of data frame 2118 and may set its basic NAV (e.g., ...) for the remaining duration of the third duration. Figure 21(As shown in NAV 2120 in the diagram). Outside the communication range of STA 2108, STA 2109 may not receive data frame 2118 and may not update its basic NAV to the remaining duration of the third duration indicated in data frame 2118. In response to data frame 2118, AP 2104 may transmit BA frame 2122 to STA 2108.

[0239] In the example, after transmitting BA frame 2122 to STA 2108, AP 2104 may not have any further uplink and / or downlink transmissions to perform during the remainder of the first duration allocated to AP 2104. In an implementation, AP 2104 may return the remainder of the first duration to AP 2102 (also referred to as truncating the first duration). In example 2100, AP 2104 may transmit frame 2124 indicating that AP 2104 returns the first duration to AP 2102 (or indicating that AP 2104 truncates the first duration). In the example, frame 2124 may be a contention-free end (CF-end) frame. In the example, the CF-end frame may include an indication of the transmitter address (TA) of AP 2104. In the example, the CF-end frame may be a broadcast frame.

[0240] In Example 2100, upon receiving CF-end frame 2124, AP 2102 may reset its basic NAV to zero before the end of the third duration. AP 2102 may also determine that AP 2104 has returned the first duration to AP 2102. With the return of the first duration to AP 2102, AP 2102 (which is the owner of the TXOP) reverts to being the holder of the TXOP. Outside the communication range of AP 2104, STA 2106 may not receive CF-end frame 2124 and may not reset its basic NAV, which was set upon receiving data frame 2118 transmitted by STA 2008. Upon receiving CF-end frame 2124, STA 2108 may reset its intra-BSV before the end of the third duration.

[0241] Because AP 2102 has the return duration of TXOP, AP 2102 can initiate uplink and / or downlink transmissions for the remaining duration of TXOP 2110. In an implementation, AP 2102 can transmit frames to allow its associated STAs to reset their basic NAV while either of them still has a non-zero NAV. For example, an associated STA of AP 2102 that did not receive CF-end frame 2124 may still have a non-zero basic NAV. Such a STA may have already set its basic NAV based on a frame received from a STA associated with AP 2104. This frame would have been triggered by a trigger frame from AP 2104. Thus, in an implementation, AP 2102 can be configured to transmit frames to its associated STAs to allow them to reset their basic NAV when / whenever AP 2102 receives a trigger frame from a shared AP (such as AP 2104) and then the shared AP transmits CF-end.

[0242] According to this implementation, in Example 2100, after receiving CF-end frame 2124, AP 2102 can transmit frame 2126 to STA 2106 for resetting STA 2106's basic NAV. In this implementation, frame 2126 may include a CF-end frame. In this implementation, the CF-end frame may include a transmitter address (TA) indicating the identifier of AP 2104 instead of the identifier of AP 2102. Thus, when STA 2106 receives frame 2126, STA 2106 can determine that frame 2126 is an inter-BSS PPDU. Therefore, STA 2106 can use frame 2126 to reset its basic NAV. In another implementation, frame 2126 may include a trigger frame, a Multi-User Request to Send Triggered TXOP Shared (MU-RTS TXS) Triggered (MRTT) frame, or a Request to Send (RTS) frame. In this implementation, the trigger frame, MRTT frame, or RTS frame may include a basic NAV reset indication. Even if the trigger frame, MRTT frame, or RTS frame is an in-BSS PPDU, the presence of a basic NAV reset indicator in the frame allows the STA to reset its basic NAV. In implementations, the basic NAV reset indicator may be provided in one of the reserved bits (e.g., B22, B26, B53, or B63) of the common information field of the trigger frame or MRTT frame, as shown in... Figure 5 and Figure 15 As illustrated in the diagram. In another implementation, the basic NAV reset indication can be provided in the frame control field of the RTS frame. (See diagram below.) Figure 21 As shown, when receiving frame 2126, STA 2106 can reset its basic NAV before the end of the third duration (t3).

[0243] In Example 2100, when AP 2102 sends a signal to STA 2106 or other associated STAs of AP 2102 ( Figure 21 When STA 2109 transmits frame 2126 (not shown) to reset its basic NAV, it can also receive frame 2126. STA 2109 can determine that frame 2126 is an inter-BSS PPDU and can use frame 2126 to reset its basic NAV. Thus, although STA 2109's basic NAV was set when receiving a frame from another AP / STA, STA 2109 can reset its basic NAV when receiving frame 2126 from AP 2102. This eliminates or removes TXOP protection for transmissions from other AP / STAs whose basic NAV was initially set for that other AP / STA.

[0244] After transmitting frame 2126, AP 2102 can transmit frame 2128 to STA 2106 to initiate an uplink transmission. In this example, frame 2128 can be a trigger frame. Upon receiving frame 2128, the OBSS AP or OBSS STA can set its basic NAV. Thus, AP 2104 can set its basic NAV (...). Figure 21 (Not shown in the image) is set to the duration indicated in frame 2128. Similarly, STA 2108 can set its basic NAV ( Figure 21 (Not shown in the image) is set to the duration indicated in frame 2128. If STA 2109 is an associated STA of a shared AP other than AP 2104, then STA 2109 can set its basic NAV (Number of Entities) to the duration indicated in frame 2128. Figure 21 (Not shown in the image) is set to the duration indicated in frame 2128. If the duration indicated in frame 2128 is shorter than the duration of NAV 2111, STA 2109 may interfere with another AP / STA when its NAV returns to zero at the end of the duration indicated in frame 2128. If STA 2109 is an associated STA of AP 2102, STA 2109 may set its NAV within its BSS ( Figure 21 (Not shown) is set to the duration indicated in frame 2128. If its basic NAV is reset by frame 2126, STA 2109 can respond to a frame from AP 2102 and can interfere with another AP / STA.

[0245] Upon receiving frame 2128 and seeing its own address in the RA field of frame 2128, STA 2106 can determine that it will transmit an uplink frame to AP 2102. STA 2106 can then set its NAV (Network Address) within its BSS. Figure 21(Not shown in the image) is set to the duration indicated in frame 2128. In another embodiment, STA 2106 may not set its NAV within its BSS. In response to frame 2128, STA 2106 may transmit frame 2130 to AP 2102. In this example, frame 2130 may be a data frame. In this embodiment, frame 2130 may include a duration field indicating the remaining portion of frame 2128 indicated by the duration. In this example, after receiving frame 2130, AP 2102 may send a duration field to STA 2106 (not shown in the image) to indicate the duration indicated in frame 2128. Figure 21 (Not shown) transmits BA frames and can continue uplink and / or downlink transmission within TXOP 2110. In another example, AP 2102 can share the remainder of TXOP 2110 with another shared AP.

[0246] As shown in Example 2100, when the shared AP returns a TXOP to the sharing AP before the shared TXOP ends, the sharing AP can help a first STA outside the communication range of the shared AP reset its basic NAV set based on frames transmitted by the shared AP or by STAs associated with the shared AP. This allows the first STA to transmit uplink traffic to the sharing AP when triggered by the shared AP. However, the sharing AP can cause a second STA (which may be associated with the sharing AP or another shared AP) to reset its basic NAV through the same action, even if the second STA does not set its basic NAV based on frames transmitted by the shared AP or by STAs associated with the shared AP, but based on frames transmitted by another AP / STA. This may cause the second STA to interfere with the transmission of another AP / STA, rather than remaining silent during the transmission.

[0247] As further described below, embodiments of this disclosure address the aforementioned problems. In one aspect, a first AP can receive a first frame from a first STA during a portion of a Transmission Opportunity (TXOP) shared by a second AP and the first AP. Based on the first frame indicating that the first STA does not have buffered data for transmission to the first AP, the first AP can transmit a second frame to the first STA that triggers the transmission of a first truncated frame by the first STA. The first AP also transmits a second truncated frame. Thus, a STA that sets its basic NAV based on frames received from the first AP and / or the first STA can reset its basic NAV. Conversely, a STA that sets its basic NAV based on frames received from another AP / STA can not reset or update its basic NAV. Therefore, when the second AP returns to be the owner of the TXOP, the second AP can initiate uplink and / or downlink transmissions for the remaining duration of the TXOP without affecting STAs that may have already set their basic NAV based on frames received from another AP / STA.

[0248] Figure 22An example 2200 of a CTDMA process according to an embodiment is illustrated. Figure 22 As shown, Example 2200 may include APs 2202 and 2204, and STAs 2206, 2208, and 2209. APs 2202 and 2204 may be members of a multi-AP group. AP 2202 may be the sharing / master AP of the multi-AP group. AP 2204 may be a shared / slave AP of the multi-AP group. STA 2206 may be associated with AP 2202, and STA 2208 may be associated with AP 2204. STA 2209 may be associated with AP 2202 or with another AP other than AP 2204. Figure 22 (Not shown in the diagram) are associated. In Example 2200, it is assumed that APs 2202, 2204 and STA 2208 are within each other's communication range. It is further assumed that STA 2206 is outside the communication range of AP 2204, but within the communication range of AP 2202 and STA 2208. It is further assumed that STA 2209 is outside the communication range of AP 2204 and STA 2208, but within the communication range of AP 2202.

[0249] like Figure 22 As shown, the process can begin with AP 2202 transmitting MRTT frame 2212 after acquiring TXOP 2210. In an embodiment, MRTT frame 2212 may include an allocation for AP 2204. The allocation of MRTT frame 2212 may include the identifier of the shared AP and the duration allocated to the shared AP (within the TXOP). In example 2200, MRTT frame 2212 may include an allocation for AP 2204. This allocation may include a first duration of the TXOP allocated to AP 2204 (within the TXOP). Figure 22 (represented as t1). The first duration can be indicated in the allocation duration subfield of the user information list field of MRTT frame 2212. In an embodiment, the duration is specified from an AP or STA other than AP 2202, AP 2204, STA 2206, or STA 2208. Figure 22 When receiving a frame (not shown in the image) (hereinafter referred to as other AP / STA), STA 2209 may have already set its basic NAV (e.g., before the transmission of MRTT frame 2212 and for a duration longer than the first duration). Figure 22 The NAV value 2211 in the image is shown. In an embodiment, the duration field of the MRTT frame 2212 may indicate a second duration (in the image). Figure 22(represented as t2). The second duration indicated in the duration field of MRTT frame 2212 may be shorter than the first duration. This is to avoid causing the associated STA of the shared AP, which is the OBSS STA of the shared AP, to set its basic NAV for a long duration (e.g., the first duration) after receiving the MRTT frame, which would result in the associated STA not responding to trigger frames from its associated shared AP, which has TXOP during the first duration. In the implementation, setting the duration field of MRTT frame 2212 to the second duration allows AP 2202 to protect the CTS frames and / or trigger frames of the shared AP.

[0250] In Example 2200, upon receiving MRTT frame 2212, STA 2206 can set its BSS-internal NAV ( Figure 22 (not shown) is set to the second duration t2 indicated in MRTT frame 2212. Upon receiving MRTT frame 2212, STA 2208 can set its basic NAV ( Figure 22 (Not shown) is set to the second duration t2. Upon receiving MRTT frame 2212, AP 2204 can determine that AP 2202 has shared TXOP 2210 with AP 2204 for duration t1. AP 2204 can then transmit CTS frame 2214 to AP 2202 in response to MRTT frame 2212.

[0251] When receiving CTS frame 2214, AP 2202 can set its BSS intra-NAV (Navigate to Virtual Object) for the remaining duration t2. Figure 22 (Not shown in the image). After transmitting CTS frame 2214, AP 2204 can use TXOP for the remaining duration of t1. In the example, AP 2204 can send a message to STA 2208 (…). Figure 22 (Not shown in the image) transmits downlink frames. In another example, AP 2204 can trigger STA 2208 to transmit uplink frames to AP 2204.

[0252] In Example 2200, after transmitting CTS frame 2214, AP 2204 can transmit trigger frame 2216 to STA 2208 to trigger uplink transmission from STA 2208. In an embodiment, the duration field of trigger frame 2216 may indicate a third duration t3. Upon receiving trigger frame 2216, OBSS AP or OBSS STA may set its basic NAV based on the duration field of trigger frame 2216. Specifically, in Example 2200, upon receiving trigger frame 2216, AP 2202 may set its basic NAV ( Figure 22(Not shown) is set to the third duration indicated in trigger frame 2216. However, outside the communication range of AP 2204, STA 2206 may not receive trigger frame 2216 and may not set its basic NAV. Similarly, outside the communication range of AP 2204, STA 2209 may not receive trigger frame 2216 and may not update its basic NAV to the third duration indicated in trigger frame 2216.

[0253] In an embodiment, upon receiving trigger frame 2216 and seeing its own address in the RA field of trigger frame 2216, STA 2208 can determine that it wants to transmit an uplink frame to AP 2204. In an embodiment, when trigger frame 2216 is transmitted by AP 2204 associated with STA 2208, STA 2208 can set its BSS NAV (Network Address Access Parameter) to its own address. Figure 22 (Not shown) is set to the third duration indicated in trigger frame 2216. In another embodiment, STA 2208 may not set its NAV within its BSS. Subsequently, STA 2208 may transmit data frame 2218 to AP 2204. Data frame 2218 may include a duration field indicating the remaining duration of the third duration. In one example, STA 2208 may not have any additional data for transmission to AP 2204 besides the data contained in the frame body of data frame 2218. In another example, STA 2208 may not have any additional data for transmission to AP 2204. In one embodiment, data frame 2218 may include a buffer status report (BSR) indicating that STA 2208 does not have buffered data for transmission to AP 2204. In another embodiment, data frame 2218 may include a more data (MD) field indicating that STA 2208 does not have buffered data for transmission to AP 2204.

[0254] When receiving data frame 2218, STA 2206 can process the duration field of data frame 2218 and can set its basic NAV (e.g., ...) for the remaining duration of the third duration. Figure 22 (As shown in NAV 2220). Outside the communication range of STA 2208, STA 2209 may not receive data frame 2218 and may not update its basic NAV to the remaining duration of the third duration indicated in data frame 2218. In response to data frame 2218, AP 2204 may transmit BA frame 2222 to STA 2208.

[0255] In the example, after transmitting BA frame 2222 to STA 2208, AP 2204 may not have any additional downlink transmissions to perform during the remainder of the first duration allocated to AP 2204. Additionally, AP 2204 may not have any additional uplink frames to receive during the remainder of the first duration allocated to AP 2204. In an implementation, AP 2204 may return the remainder of the first duration to AP 2202 (also referred to as truncating the first duration). In an implementation, AP 2204 may transmit a truncated frame to reset the basic NAV of STAs that may have already set their basic NAV based on frames received from AP 2204. Additionally, AP 2204 may trigger associated STAs to transmit similar truncated frames. This allows STAs outside the communication range of AP 2204 that may have already set their basic NAV based on frames transmitted by associated STAs during the first duration to also reset their basic NAV.

[0256] In Example 2200, based on a data frame 2218 indicating that STA 2208 does not have buffered data for transmission to AP 2204, AP 2204 may transmit frame 2224 to STA 2208, triggering the transmission of truncated frame 2226 by STA 2208. In this example, frame 2224 triggers the transmission of truncated frame 2226 by STA 2208 at a short inter-frame interval (SIFS) following the reception of frame 2224. In this example, frame 2224 may be a trigger frame. In another example, frame 2224 may be a polling frame. In this example, truncated frame 2226 may cause STA 2206 to reset its basic NAV, which STA 2206 may have already set based on data frame 2218 transmitted by STA 2208. In this example, truncated frame 2226 may include a contention-free end (CF-end) frame. In this example, the CF-end frame may include an indication of the transmitter address (TA) of AP 2204. In the example, the CF-end frame can be a broadcast frame. Upon receiving truncated frame 2226, STA 2206 can reset its basic NAV to zero before the end of the third duration. On the other hand, STA 2209 can choose not to receive truncated frame 2226, and therefore, STA 2209 can choose not to reset its basic NAV setting to NAV value 2211.

[0257] In example 2200, after transmitting frame 2224, AP 2204 may transmit truncated frame 2228. In this example, truncated frame 2228 may reset the basic NAV of AP 2202 or the basic NAV of the STA associated with AP 2202. In this example, the basic NAV of AP 2202 may be set by data frame 2218. In another example, the basic NAV of the STA associated with AP 2202 may be set by data frame 2218. In yet another example, the basic NAV of AP 2202 may be set by trigger frame 2216. In this example, truncated frame 2228 may include a CF-end frame. In this example, the CF-end frame may include an indication of the transmitter address (TA) of AP 2204. Upon receiving truncated frame 2228, AP 2202 or the STA associated with AP 2202 may reset its basic NAV to zero before the end of the third duration. On the other hand, since STA 2209 may not receive truncated frame 2228, STA 2209 may not reset its basic NAV setting to NAV value 2211.

[0258] In example 2200, transmitting truncated frame 2228 by AP 2204 may include transmitting truncated frame 2228 concurrently with transmitting truncated frame 2226 by STA 2208. In another example, transmitting truncated frame 2228 by AP 2204 may include transmitting truncated frame 2228 simultaneously with transmitting truncated frame 2226 by STA 2208. In another example, transmitting truncated frame 2228 by AP 2204 may include transmitting truncated frame 2228 at a short inter-frame interval (SIFS) following frame 2224. In another example, transmitting truncated frame 2228 by AP 2204 may include transmitting truncated frame 2228 during a time period overlapping with that of truncated frame 2226 transmitted by STA 2208. The main advantage of AP 2204 transmitting truncated frames during the period overlapping with STA 2208's transmission of truncated frames is that the SIFS of AP 2202 can become the owner of the TXOP after hearing the overlapping truncated frames, where the content of the truncated frames is identical. AP 2202 may not need to evaluate whether multiple truncated frames have been received.

[0259] In Example 2200, AP 2202 can receive multiple truncated frames. In this example, AP 2202 can receive truncated frames concurrently. In another example, AP 2202 can receive truncated frames separated by SIFS durations. Upon receiving truncated frames 2226 and / or truncated frame 2228, AP 2202 can reset its basic NAV to zero before the end of the third duration. AP 2202 can also determine that AP 2204 has returned the first duration to AP 2202. With the first duration returned to AP 2202, AP 2202 (which is the owner of the TXOP) returns to being the holder of the TXOP. AP 2202 can transmit frame 2230 to STA 2206 to initiate an uplink transmission. In this example, AP 2202 can transmit frame 2230a during SIFS after receiving truncated frame 2228. In another example, AP 2202 can transmit frame 2230 via Point Coordination Function (PCF) IFS (PIFS) after receiving truncated frame 2228, where PIFS is one slot longer than SIFS. In this example, frame 2230 can be a trigger frame. Upon receiving frame 2230, the OBSS AP or OBSS STA can set its basic NAV. Thus, AP 2204 can set its basic NAV (... Figure 22 (Not shown in the image) is set to the duration indicated in frame 2230. Similarly, STA 2208 can set its basic NAV ( Figure 22 (Not shown in the image) is set to the duration indicated in frame 2230. Furthermore, if the duration indicated in frame 2230 is longer than the NAV value 2211, STA 2209 may update its basic NAV duration. If the duration indicated in frame 2230 is shorter than the NAV value 2211, STA 2209 maintains its basic NAV set to the NAV value 2211.

[0260] Upon receiving frame 2230 and seeing its own address in the RA field of frame 2230, STA 2206 can determine that it will transmit an uplink frame to AP 2202. STA 2206 can then set its NAV (Network Address) within its BSS. Figure 22 (Not shown in the image) is set to the duration indicated in frame 2230. In another embodiment, STA 2206 may not set its in-BSN NAV. In response to frame 2230, STA 2206 may transmit frame 2232 to AP 2202. In this example, frame 2232 may be a data frame. In this implementation, frame 2232 may include a duration field indicating the remaining portion of frame 2230, which indicates the duration. In this example, after receiving frame 2232, AP 2202 may send a duration field to STA 2206 (not shown in the image) to indicate the duration indicated in frame 2230. Figure 22(Not shown in the diagram) BA frames are transmitted, and uplink and / or downlink transmission can continue within TXOP 2210. In another example, AP 2202 can share the remainder of TXOP 2210 with another shared AP. As shown in Example 2200, when the shared AP returns the TXOP to the sharing AP before the shared TXOP ends (by transmitting a truncated frame), by causing the STA associated with the shared AP to also transmit the truncated frame, a STA that has already set its basic NAV based on communication between the shared AP and its associated STA is allowed to successfully reset its basic NAV. However, the truncated frame does not affect STAs that may have already set their basic NAV based on communication from another AP / STA that is not part of the shared AP's BSS. Such STAs maintain their basic NAV as needed to protect against communication from other AP / STAs.

[0261] Figure 23 An example 2300 of a CTDMA process according to an embodiment is illustrated. Figure 23 As shown, Example 2300 may include APs 2302 and 2304, and STAs 2306, 2308, and 2309. APs 2302 and 2304 may be members of a multi-AP group. AP 2302 may be the sharing / master AP of the multi-AP group. AP 2304 may be a shared / slave AP of the multi-AP group. STA 2306 may be associated with AP 2302, and STA 2308 may be associated with AP 2304. STA 2309 may be associated with AP 2302 or with another AP other than AP 2304. Figure 23 (Not shown in the diagram) are associated. In Example 2300, it is assumed that APs 2302, 2304 and STA 2308 are within each other's communication range. It is further assumed that STA 2306 is outside the communication range of AP 2304, but within the communication range of AP 2302 and STA 2308. It is further assumed that STA 2309 is outside the communication range of AP 2304 and STA 2308, but within the communication range of AP 2302.

[0262] like Figure 23 As shown, the process can begin with AP 2302 transmitting MRTT frame 2312 after acquiring TXOP 2310. In an embodiment, MRTT frame 2312 may include an allocation for AP 2304. The allocation of MRTT frame 2312 may include the identifier of the shared AP and the duration allocated to the shared AP (within the TXOP). In example 2300, MRTT frame 2312 may include an allocation for AP 2304. This allocation may include a first duration of the TXOP allocated to AP 2304 (within the TXOP). Figure 23(represented as t1). The first duration can be indicated in the allocation duration subfield of the user information list field of MRTT frame 2312. In an embodiment, the duration is specified from an AP or STA other than AP 2302, AP 2304, STA 2306, or STA 2308. Figure 23 When receiving a frame (not shown in the image) (hereinafter referred to as other AP / STA), STA 2309 may have already set its basic NAV (e.g., before the transmission of MRTT frame 2312 and for a duration longer than the first duration). Figure 23 The NAV value 2311 in the image is shown. In an embodiment, the duration field of the MRTT frame 2312 may indicate a second duration (in the image). Figure 23 (represented as t2). The second duration indicated in the duration field of MRTT frame 2312 may be shorter than the first duration. This is to avoid causing the associated STA of the shared AP, which is the OBSS STA of the shared AP, to set its basic NAV for a long duration (e.g., the first duration) after receiving the MRTT frame, which would result in the associated STA not responding to trigger frames from its associated shared AP, which has TXOP during the first duration. In the implementation, setting the duration field of MRTT frame 2312 to the second duration allows AP 2302 to protect the CTS frames and / or trigger frames of the shared AP.

[0263] In Example 2300, upon receiving MRTT frame 2312, STA 2306 can set its BSS-internal NAV ( Figure 23 (not shown) is set to the second duration t2 indicated in MRTT frame 2312. Upon receiving MRTT frame 2312, STA 2308 can set its basic NAV ( Figure 23 (Not shown) is set to the second duration t2. Upon receiving MRTT frame 2312, AP 2304 can determine that AP 2302 has shared TXOP 2310 with AP 2304 for duration t1. AP 2304 can then transmit CTS frame 2314 to AP 2302 in response to MRTT frame 2312.

[0264] When receiving CTS frame 2314, AP 2302 can set its BSS-internal NAV (Navigate to Virtual Object) for the remaining duration t2. Figure 23 (Not shown in the image). After transmitting CTS frame 2314, AP 2304 can use TXOP for the remaining duration of t1. In the example, AP 2304 can send a TXOP to STA 2308 (…). Figure 23 (Not shown in the image) transmits downlink frames. In another example, AP 2304 can trigger STA 2308 to transmit uplink frames to AP 2304.

[0265] In Example 2300, after transmitting CTS frame 2314, AP 2304 can transmit trigger frame 2316 to STA 2308 to trigger uplink transmission from STA 2308. In an embodiment, the duration field of trigger frame 2316 can indicate a third duration t3. Upon receiving trigger frame 2316, OBSS AP or OBSS STA can set its basic NAV based on the duration field of trigger frame 2316. Specifically, in Example 2300, upon receiving trigger frame 2316, AP 2302 can set its basic NAV ( Figure 23 (Not shown) is set to the third duration indicated in trigger frame 2316. However, outside the communication range of AP 2304, STA 2306 may not receive trigger frame 2316 and may not set its basic NAV. Similarly, outside the communication range of AP 2304, STA 2309 may not receive trigger frame 2316 and may not update its basic NAV to the third duration indicated in trigger frame 2316.

[0266] In an embodiment, upon receiving trigger frame 2316 and seeing its own address in the RA field of trigger frame 2316, STA 2308 can determine that it wants to transmit an uplink frame to AP 2304. In an embodiment, when trigger frame 2316 is transmitted by AP 2304 associated with STA 2308, STA 2308 can set its BSS NAV (Network Address Access Parameter) to its own address. Figure 23 (Not shown) is set to the third duration indicated in trigger frame 2316. In another embodiment, STA 2308 may not set its NAV within its BSS. Subsequently, STA 2308 may transmit data frame 2318 to AP 2304. Data frame 2318 may include a duration field indicating the remaining duration of the third duration. In one example, STA 2308 may not have any additional data for transmission to AP 2304 besides the data contained in the frame body of data frame 2318. In another example, STA 2308 may not have any additional data for transmission to AP 2304. In one embodiment, data frame 2318 may include a buffer status report (BSR) indicating that STA 2308 does not have buffered data for transmission to AP 2304. In another embodiment, data frame 2318 may include a more data (MD) field indicating that STA 2308 does not have buffered data for transmission to AP 2304.

[0267] When receiving data frame 2318, STA 2306 can process the duration field of data frame 2318 and can set its basic NAV (e.g., ...) for the remaining duration of the third duration. Figure 23 (As shown in NAV 2320 in the data). Outside the communication range of STA 2308, STA 2309 may not receive data frame 2318 and may not update its basic NAV to the remaining duration of the third duration indicated in data frame 2318. In response to data frame 2318, AP 2304 may transmit BA frame 2322 to STA 2308.

[0268] In the example, after transmitting BA frame 2322 to STA 2308, AP 2304 may not have any additional downlink transmissions to perform during the remainder of the first duration allocated to AP 2304. Additionally, AP 2304 may not have any additional uplink frames to receive during the remainder of the first duration allocated to AP 2304. In an implementation, AP 2304 may return the remainder of the first duration to AP 2302 (also referred to as truncating the first duration). In an implementation, AP 2304 may transmit a truncated frame to reset the basic NAV of an STA that may have already set its basic NAV based on frames received from AP 2304. Additionally, AP 2304 may trigger an associated STA to transmit a similar truncated frame. This allows STAs outside the communication range of AP 2304 that may have already set their basic NAV based on frames transmitted by the associated STA during the first duration to also reset their basic NAV.

[0269] In Example 2300, based on a data frame 2318 indicating that STA 2308 does not have buffered data for transmission to AP 2304, AP 2304 may transmit frame 2324 to STA 2308, triggering the transmission of truncated frame 2326 by STA 2308. In this example, frame 2324 triggers the transmission of truncated frame 2326 by STA 2308 at a short inter-frame interval (SIFS) following the reception of frame 2324. In this example, frame 2324 may be a trigger frame. In another example, frame 2324 may be a polling frame. In this example, truncated frame 2326 may cause STA 2306 to reset its basic NAV, which STA 2306 may have already set based on data frame 2318 transmitted by STA 2308. In this example, truncated frame 2326 may include a contention-free end (CF-end) frame. In this example, the CF-end frame may include an indication of the transmitter address (TA) of AP 2304. In the example, the CF-end frame can be a broadcast frame. Upon receiving truncated frame 2326, STA 2306 can reset its basic NAV to zero before the end of the third duration. On the other hand, STA 2309 can choose not to receive truncated frame 2326, and therefore, STA 2309 can choose not to reset its basic NAV setting to NAV value 2311.

[0270] In example 2300, after transmitting frame 2324, AP 2304 may transmit truncated frame 2328. In this example, truncated frame 2328 may reset the basic NAV of AP 2302 or the basic NAV of the STA associated with AP 2302. In this example, the basic NAV of AP 2302 may be set by data frame 2318. In another example, the basic NAV of the STA associated with AP 2302 may be set by data frame 2318. In yet another example, the basic NAV of AP 2302 may be set by trigger frame 2316. In this example, truncated frame 2328 may include a CF-end frame. In this example, the CF-end frame may include an indication of the transmitter address (TA) of AP 2304. Upon receiving truncated frame 2328, AP 2302 or the STA associated with AP 2302 may reset its basic NAV to zero before the end of the third duration. On the other hand, since STA 2309 can choose not to receive truncated frame 2328, STA 2309 can choose not to reset its basic NAV setting to NAV value 2311.

[0271] In Example 2300, AP 2304 can transmit truncated frame 2328 at a short inter-frame interval (SIFS) after STA 2308 transmits truncated frame 2326.

[0272] In Example 2300, AP 2302 can receive one or more truncated frames. In this example, AP 2302 can receive only truncated frame 2328 and reset its basic NAV based on truncated frame 2328. In another example, AP 2302 can receive truncated frames 2326 and 2328 separated by SIFS durations. Upon receiving truncated frames 2326 and / or 2328, AP 2302 can reset its basic NAV to zero before the end of the third duration. AP 2302 can also determine that AP 2304 has returned the first duration to AP 2302. With the first duration returned to AP 2302, AP 2302 (which is the owner of the TXOP) returns to being the holder of the TXOP. AP 2302 can transmit frame 2330 to STA 2306 to initiate an uplink transmission. In this example, AP 2302 can transmit frame 2330 during SIFS after receiving truncated frame 2328. In another example, AP 2302 can receive multiple truncated frames separated from each other by the SIFS duration. AP 2302 can determine the last truncated frame among the multiple truncated frames and can transmit frame 2330 after receiving the last truncated frame for a PIFS (where the PIFS is one slot longer than the SIFS). In an implementation, AP 2302 can determine the last truncated frame as one in which AP 2302 has not received any other truncated frames after it (e.g., after waiting for at least the SIFS duration after receiving the truncated frame). In the example, frame 2330 can be a trigger frame. Upon receiving frame 2330, the OBSS AP or OBSS STA can set its basic NAV. For example, AP 2304 can set its basic NAV ( Figure 23 (Not shown in the image) is set to the duration indicated in frame 2330. Similarly, STA2308 can set its basic NAV (... Figure 23 (Not shown in the image) is set to the duration indicated in frame 2330. Furthermore, if the duration indicated in frame 2330 is longer than the NAV value 2311, STA 2309 may update its basic NAV duration. If the duration indicated in frame 2330 is shorter than the NAV value 2311, STA 2309 maintains its basic NAV set to the NAV value 2311.

[0273] Upon receiving frame 2330 and seeing its own address in the RA field of frame 2330, STA 2306 can determine that it will transmit an uplink frame to AP 2302. STA 2306 can then set its NAV (Network Address) within its BSS. Figure 23(Not shown in the image) is set to the duration indicated in frame 2330. In another embodiment, STA 2306 may not set its NAV within its BSS. In response to frame 2330, STA 2306 may transmit frame 2332 to AP 2302. In this example, frame 2332 may be a data frame. In this implementation, frame 2332 may include a duration field indicating the remaining portion of frame 2330, which indicates the duration. In this example, after receiving frame 2332, AP 2302 may send a duration field to STA 2306 (not shown in the image) to indicate the duration indicated in frame 2330. Figure 23 (Not shown in the diagram) BA frames are transmitted, and uplink and / or downlink transmission can continue within TXOP 2310. In another example, AP 2302 can share the remainder of TXOP 2310 with another shared AP. As shown in Example 2300, when the shared AP returns the TXOP to the sharing AP before the shared TXOP ends (by transmitting a truncated frame), by causing the STA associated with the shared AP to also transmit the truncated frame, a STA that has already set its basic NAV based on communication between the shared AP and its associated STA is allowed to successfully reset its basic NAV. However, the truncated frame does not affect STAs that may have already set their basic NAV based on communication from another AP / STA that is not part of the shared AP's BSS. Such STAs maintain their basic NAV as needed to protect against communication from other APs / STAs.

[0274] Figure 24 An example 2400 of a CTDMA process according to an embodiment is illustrated. Figure 24 As shown, Example 2400 may include APs 2402 and 2404, and STAs 2406, 2408, and 2409. APs 2402 and 2404 may be members of a multi-AP group. AP 2402 may be the sharing / master AP of the multi-AP group. AP 2404 may be a shared / slave AP of the multi-AP group. STA 2406 may be associated with AP 2402, and STA 2408 may be associated with AP 2404. STA 2409 may be associated with AP 2402 or with another AP other than AP 2404. Figure 24 (Not shown in the diagram) are associated. In Example 2400, it is assumed that APs 2402, 2404 and STA 2408 are within each other's communication range. It is further assumed that STA 2406 is outside the communication range of AP 2404, but within the communication range of AP 2402 and STA 2408. It is further assumed that STA 2409 is outside the communication range of AP 2404 and STA 2408, but within the communication range of AP 2402.

[0275] like Figure 24As shown, the process can begin with AP 2402 transmitting MRTT frame 2412 after acquiring TXOP 2410. In an embodiment, MRTT frame 2412 may include an allocation for AP 2404. The allocation of MRTT frame 2412 may include the identifier of the shared AP and the duration allocated to the shared AP (within the TXOP). In example 2400, MRTT frame 2412 may include an allocation for AP 2404. This allocation may include a first duration of the TXOP allocated to AP 2404 (within the TXOP). Figure 24 (represented as t1). The first duration can be indicated in the allocation duration subfield of the user information list field in MRTT frame 2412. In an embodiment, the duration is specified for APs or STAs other than AP 2402, AP 2404, STA 2406, or STA 2408. Figure 24 When receiving a frame (not shown in the image) (hereinafter referred to as other AP / STA), STA 2409 may have already set its basic NAV (e.g., before the transmission of MRTT frame 2412 and for a duration longer than the first duration). Figure 24 The NAV value 2411 in the image is shown. In an embodiment, the duration field of the MRTT frame 2412 can indicate a second duration (in the image). Figure 24 (represented as t2). The second duration indicated in the duration field of MRTT frame 2412 can be shorter than the first duration. This is to avoid causing the associated STA of the shared AP, which is the OBSS STA of the shared AP, to set its basic NAV for a long duration (e.g., the first duration) after receiving the MRTT frame, which would result in the associated STA not responding to trigger frames from its associated shared AP, which has TXOP during the first duration. In the implementation, setting the duration field of MRTT frame 2412 to the second duration allows AP 2402 to protect the CTS frames and / or trigger frames of the shared AP.

[0276] In Example 2400, upon receiving MRTT frame 2412, STA 2406 can set its BSS-internal NAV ( Figure 24 (not shown) is set to the second duration t2 indicated in MRTT frame 2412. Upon receiving MRTT frame 2412, STA 2408 can set its basic NAV ( Figure 24 (Not shown) is set to the second duration t2. Upon receiving MRTT frame 2412, AP 2404 can determine that AP 2402 has shared TXOP 2410 with AP 2404 for duration t1. AP 2404 can transmit CTS frame 2414 to AP 2402 in response to MRTT frame 2412.

[0277] When receiving CTS frame 2414, AP 2402 can set its BSS-internal NAV (Navigate to Virtual Object) for the remaining duration t2. Figure 24 (Not shown in the image). After transmitting CTS frame 2414, AP 2404 can use TXOP for the remaining duration of t1. In the example, AP 2404 can send a message to STA 2408 (…). Figure 24 (Not shown in the image) transmits downlink frames. In another example, AP 2404 can trigger STA 2408 to transmit uplink frames to AP 2404.

[0278] In Example 2400, after transmitting CTS frame 2414, AP 2404 can transmit trigger frame 2416 to STA 2408 to trigger uplink transmission from STA 2408. In an embodiment, the duration field of trigger frame 2416 can indicate a third duration t3. Upon receiving trigger frame 2416, OBSS AP or OBSS STA can set its basic NAV based on the duration field of trigger frame 2416. Specifically, in Example 2400, upon receiving trigger frame 2416, AP 2402 can set its basic NAV ( Figure 24 (Not shown) is set to the third duration indicated in trigger frame 2416. However, outside the communication range of AP 2404, STA 2406 may not receive trigger frame 2416 and may not set its basic NAV. Similarly, outside the communication range of AP 2404, STA 2409 may not receive trigger frame 2416 and may not update its basic NAV to the third duration indicated in trigger frame 2416.

[0279] In an embodiment, upon receiving trigger frame 2416 and seeing its own address in the RA field of trigger frame 2416, STA 2408 can determine that it wants to transmit an uplink frame to AP 2404. In an embodiment, when trigger frame 2416 is transmitted by AP 2404 associated with STA 2408, STA 2408 can set its BSS NAV (Network Address Access Parameter) to its own address. Figure 24(Not shown) is set to the third duration indicated in trigger frame 2416. In another embodiment, STA 2408 may not set its NAV within its BSS. Subsequently, STA 2408 may transmit data frame 2418 to AP 2404. Data frame 2418 may include a duration field indicating the remaining duration of the third duration. In this example, STA 2408 may not have any additional data for transmission to AP 2404 besides the data contained in the frame body of data frame 2418. In another example, STA 2408 may not have any additional data for transmission to AP 2404. In this embodiment, data frame 2418 may include a buffer status report (BSR) indicating that STA 2408 does not have buffered data for transmission to AP 2404. In another embodiment, data frame 2418 may include a more data (MD) field indicating that STA 2408 does not have buffered data for transmission to AP 2404.

[0280] When receiving data frame 2418, STA 2406 can process the duration field of data frame 2418 and can set its basic NAV (e.g., ...) for the remaining duration of the third duration. Figure 24 (As shown in NAV 2420 in the data). Outside the communication range of STA 2408, STA 2409 may not receive data frame 2418 and may not update its basic NAV to the remaining duration of the third duration indicated in data frame 2418.

[0281] In the example, after receiving data frame 2418 from STA 2408, AP 2404 may not have any additional uplink and / or downlink transmissions to perform during the remainder of the first duration allocated to AP 2404. In the example, AP 2404 may not have any additional uplink frames to receive during the remainder of the first duration allocated to AP 2404. In an implementation, AP 2404 may return the remainder of the first duration to AP 2402 (also referred to as truncating the first duration). In an implementation, AP 2404 may transmit a truncated frame for resetting the basic NAV of STAs that may have already set their basic NAV based on frames received from AP 2404. Considering that there may be STAs outside the communication range of AP 2404 that may have already set their basic NAV based on communication between AP 2404 and its associated STAs (such as STA 2408), AP 2404 may be configured to notify those associated STAs that may have already transmitted frames during the first duration of the (planned) truncation of the first duration.

[0282] In Example 2400, based on Data Frame 2418 indicating that STA 2408 has no buffered data to transmit to AP 2404, and in response to Data Frame 2418, AP 2404 may transmit BA Frame 2422 to STA 2408, thereby notifying STA 2408 of a truncation of a first duration at AP 2404. In this example, BA Frame 2422 may include an indication to STA 2408 of the truncation of the first duration at AP 2404, which may be provided in the Frame Control Field, BA Control Field, or BA Information Field of BA Frame 2422. In this example, after transmitting BA Frame 2422, AP 2404 may transmit Truncation Frame 2424. In this example, Truncation Frame 2424 may be aggregated with BA Frame 2422. In this example, Truncation Frame 2424 may cause a reset of the basic NAV of AP 2402 or the STA associated with AP 2402. In the example, the basic NAV of AP 2402 can be set by data frame 2418. In another example, the basic NAV of the associated STA of AP 2402 can be set by data frame 2418 ( Figure 24 (Not shown in the image) In another example, AP 2404 may transmit trigger frame 2416 to STA 2408 during a portion of the TXOP shared by AP 2402 and AP 2404. Thus, the basic NAV of AP 2402 can be set by trigger frame 2416. In this example, truncated frame 2424 may include a contention-free end (CF-end) frame. In this example, the CF-end frame may include an indication of the transmitter address (TA) of AP 2404. Upon receiving truncated frame 2424, AP 2402 may reset its basic NAV to zero before the end of the third duration. On the other hand, STA 2409 may not receive truncated frame 2424, therefore, STA 2409 may not reset its basic NAV setting to NAV value 2411. Similarly, STA 2406 may not receive truncated frame 2424, therefore, STA 2406 may not reset its basic NAV setting to NAV value 2420.

[0283] In Example 2400, STA 2408 may transmit truncated frame 2426 after AP 2404 transmits truncated frame 2424. In one embodiment, STA 2408 may transmit truncated frame 2426 at a short inter-frame interval (SIFS) following the transmission of truncated frame 2424. In another embodiment, STA 2408 may transmit truncated frame 2426 at the SIFS following the transmission of truncated frame 2424, wherein truncated frame 2424 is aggregated with BA frame 2422. In the example, truncated frame 2426 may cause a reset of the basic NAV of STA 2406, which STA 2406 may have already set based on data frame 2418. In the example, truncated frame 2426 may include a contention-free end (CF-end) frame. In the example, the CF-end frame may include an indication of the transmitter address (TA) of AP 2404. In the example, the CF-end frame may be a broadcast frame. Upon receiving truncated frame 2426, STA 2406 may reset its basic NAV to zero before the end of the third duration. On the other hand, STA 2409 may not receive truncated frame 2426, and therefore STA 2409 may not reset its basic NAV setting to NAV value 2411.

[0284] In another example ( Figure 24 In (not shown), STA 2408 can transmit truncated frame 2426 after receiving BA frame 2422 and before AP 2404 transmits truncated frame 2424.

[0285] In Example 2400, AP 2402 can receive one or more truncated frames. In this example, AP 2402 can receive only truncated frame 2424 and reset its basic NAV. In another example, AP 2402 can receive truncated frames 2424 and 2426, separated by SIFS durations. Upon receiving truncated frames 2424 and / or 2426, AP 2402 can reset its basic NAV to zero before the end of the third duration. AP 2402 can also determine that AP 2404 has returned the first duration to AP 2402. With the first duration returned to AP 2402, AP 2402 (which is the owner of the TXOP) returns to being the holder of the TXOP. AP 2402 can transmit frame 2428 to STA 2406 to initiate an uplink transmission. In this example, AP 2402 can transmit frame 2428 during SIFS after receiving truncated frame 2426. In another example, AP 2402 can receive multiple truncated frames separated from each other by the SIFS duration. AP 2402 can determine the last truncated frame among the multiple truncated frames and can transmit frame 2428 after receiving the last truncated frame for a PIFS (where the PIFS is one slot longer than the SIFS). In an implementation, AP 2402 can determine the last truncated frame as one in which AP 2402 has not received any other truncated frames after it (e.g., after waiting for at least the SIFS duration after receiving the truncated frame). In this example, frame 2428 can be a trigger frame. Upon receiving frame 2428, the OBSS AP or OBSS STA can set its basic NAV. Thus, AP 2404 can set its basic NAV ( Figure 24 (Not shown in the image) is set to the duration indicated in frame 2428. Similarly, STA 2408 can set its basic NAV ( Figure 24 (Not shown in the image) is set to the duration indicated in frame 2428. Furthermore, if the duration indicated in frame 2428 is longer than the NAV value 2411, STA 2409 may update its basic NAV duration. If the duration indicated in frame 2428 is shorter than the NAV value 2411, STA 2409 maintains its basic NAV set to the NAV value 2411.

[0286] Upon receiving frame 2428 and seeing its own address in the RA field of frame 2428, STA 2406 can determine that it will transmit an uplink frame to AP 2402. STA 2406 can then set its NAV (Network Address) within its BSS. Figure 24(Not shown in the image) is set to the duration indicated in frame 2428. In another embodiment, STA 2406 may not set its in-BSS NAV. In response to frame 2428, STA 2406 may transmit frame 2430 to AP 2402. In this example, frame 2430 may be a data frame. In this implementation, frame 2430 may include a duration field indicating the remaining portion of frame 2428 indicated by the duration. In this example, after receiving frame 2430, AP 2402 may send a message to STA 2406 (not shown in the image) to indicate the duration indicated in frame 2428. Figure 24 (Not shown in the diagram) BA frames are transmitted, and uplink and / or downlink transmission can continue within TXOP 2410. In another example, AP 2402 can share the remainder of TXOP 2410 with another shared AP. As shown in Example 2400, when the shared AP returns the TXOP to the sharing AP before the shared TXOP ends (by transmitting a truncated frame), by causing the STA associated with the shared AP to also transmit the truncated frame, a STA that has already set its basic NAV based on communication between the shared AP and its associated STA is allowed to successfully reset its basic NAV. However, the truncated frame does not affect STAs that may have already set their basic NAV based on communication from another AP / STA that is not part of the shared AP's BSS. Such STAs maintain their basic NAV as needed to protect against communication from other APs / STAs.

[0287] Figure 25 An example process 2500 according to an embodiment is illustrated. The example process 2500 is provided for illustrative purposes only and is not intended to be limiting. The example process 2500 may be performed by a first AP (such as, for example, AP 2204, AP 2304, or AP 2404).

[0288] like Figure 25 As shown, process 2500 may include: in step 2510, during a portion of the TXOP shared by the second AP and the first AP, the first AP receives a first frame from the first STA. In an embodiment, the first frame may include a data frame. In an embodiment, the data frame may include a Buffer Status Report (BSR) indicating that the first STA does not have buffered data for transmission to the first AP. In another embodiment, the data frame may include a More Data (MD) field indicating that the first STA does not have buffered data for transmission to the first AP.

[0289] Process 2500 may further include: in step 2520, based on a first frame indicating that the first STA does not have buffered data for transmission to the first AP: a second frame is transmitted from the first AP to the first STA, the second frame triggering the transmission of a first truncated frame by the first STA; and a second truncated frame is transmitted by the first AP. In an embodiment, the first truncated frame may be used to reset the first basic network allocation vector (NAV) of the second STA. In an embodiment, the first basic NAV of the second STA may be set by the first frame. In an embodiment, the first truncated frame may include a contention-free end (CF-End) frame. In an embodiment, the CF-End frame may include an indication of the transmitter address (TA) of the first AP. In an embodiment, the second STA may be associated with a second AP.

[0290] In one embodiment, the second truncated frame may be used to reset the second basic NAV of the third STA. In another embodiment, the second truncated frame may include a contention-free end (CF-End) frame. In another embodiment, the CF-End frame may include an indicator of the transmitter address (TA) of the first AP. In another embodiment, the second basic NAV of the third STA may be set by the first frame. In another embodiment, process 2500 may further include transmitting a third frame from the first AP to the first STA during a portion of the TXOP shared by the second AP and the first AP. In another embodiment, the third frame may include a trigger frame. In another embodiment, the second basic NAV of the third STA may be set by the third frame. In another embodiment, the third STA may be associated with the second AP. In yet another embodiment, the third STA may include the second AP.

[0291] In one embodiment, the second frame may trigger the transmission of a first truncated frame by the first STA during a short inter-frame interval (SIFS) following the reception of the second frame. In another embodiment, transmitting the second truncated frame may include transmitting the second truncated frame concurrently with the transmission of the first truncated frame by the first STA. In yet another embodiment, transmitting the second truncated frame may include transmitting the second truncated frame simultaneously with the transmission of the first truncated frame by the first STA. In yet another embodiment, transmitting the second truncated frame may include transmitting the second truncated frame during a short inter-frame interval (SIFS) following the second frame. In yet another embodiment, transmitting the second truncated frame may include transmitting the second truncated frame during a time period overlapping with the transmission of the first truncated frame by the first STA.

[0292] In another embodiment, transmitting the second truncated frame may include transmitting the second truncated frame during a short inter-frame interval (SIFS) following the transmission of the first truncated frame by the first STA.

[0293] In another embodiment, transmitting the second truncated frame may include transmitting the second truncated frame before the first truncated frame is transmitted by the first STA. In another embodiment, transmitting the second truncated frame may include transmitting the second truncated frame during a short inter-frame interval (SIFS) prior to the first truncated frame being transmitted by the first STA. In another embodiment, process 2500 may further include transmitting a block acknowledgment (BA) frame before transmitting the second truncated frame. In another embodiment, the second truncated frame may be aggregated into a BA frame.

[0294] Figure 26 Another example process 2600 according to an embodiment is illustrated. The example process 2600 is provided for illustrative purposes only and is not intended to be limiting. The example process 2600 may be performed by a first STA (such as, for example, STA 2208, STA 2308, or STA 2408).

[0295] like Figure 26 As shown, process 2600 may include: in step 2610, during a portion of the TXOP shared by the second AP and the first AP, a first frame is transmitted from the first STA to the first AP, wherein the first frame indicates whether the first STA has buffered data for transmission to the first AP. In an embodiment, the first frame may include a data frame. In an embodiment, the data frame may include a Buffer Status Report (BSR) indicating that the first STA does not have buffered data for transmission to the first AP. In another embodiment, the data frame may include a More Data (MD) field indicating that the first STA does not have buffered data for transmission to the first AP.

[0296] Process 2600 may further include: in step 2620, a second frame is received by the first STA from the first AP, the second frame triggering the transmission of a first truncated frame by the first STA. In an embodiment, process 2600 may further include the transmission of the first truncated frame by the first STA. In an embodiment, the first truncated frame may be used to reset the first basic network allocation vector (NAV) of the second STA. In an embodiment, the first basic NAV of the second STA may be set by the first frame. In an embodiment, the first truncated frame may include a contention-free end (CF-End) frame. In an embodiment, the CF-End frame may include an indication of the transmitter address (TA) of the first AP. In an embodiment, the second STA may be associated with a second AP.

[0297] In an embodiment, process 2600 may further include the first STA receiving a third frame from the first AP during a portion of the TXOP shared by the second AP and the first AP. In an embodiment, the third frame may include a trigger frame. In an embodiment, the third frame may set a second basic NAV for the third STA. In an embodiment, the third STA may be associated with the second AP. In another embodiment, the third STA may include the second AP.

[0298] In one embodiment, the second frame may trigger the transmission of the first truncated frame by the first STA during a short inter-frame interval (SIFS) following the reception of the second frame. In another embodiment, the first AP may transmit the second truncated frame, wherein transmitting the first truncated frame may include transmitting the first truncated frame after the second truncated frame. In yet another embodiment, the first AP may transmit the second truncated frame, wherein transmitting the first truncated frame may include transmitting the first truncated frame during a short inter-frame interval (SIFS) following the second truncated frame.

Claims

1. A method comprising: During a portion of the transmission opportunity (TXOP) shared by the second access point (AP) and the first AP, the first AP transmits the first frame to the first station (STA); The first AP receives the second frame in response to the first STA from the first STA; Perform the following operations based on the second frame indicating that the first STA does not have buffered data for transmission to the first AP: The first AP transmits a third frame to the first STA, and the third frame triggers the first STA to transmit a first truncated frame to reset the first basic network allocation vector (NAV) of the second STA; and The first AP transmits a second truncated frame to reset the second basic NAV of the third STA.

2. A method comprising: During a portion of the transmission opportunity (TXOP) shared by the second access point (AP) and the first AP, the first AP receives the first frame from the first station (STA); Perform the following operations based on the first frame indicating that the first STA does not have buffered data for transmission to the first AP: The first AP transmits a second frame to the first STA, and the second frame triggers the first STA to transmit a first truncated frame. and The second truncated frame is transmitted by the first AP.

3. The method according to claim 2, wherein, The first truncated frame is used to reset the first basic network allocation vector (NAV) of the second STA.

4. The method according to claim 3, wherein, The first basic NAV of the second STA is set by the first frame.

5. The method according to any one of claims 2-3, wherein, The first truncated frame includes a contention-free end (CF-End) frame.

6. The method according to claim 5, wherein, The CF-End frame includes an indication of the transmitter address (TA) of the first AP.

7. The method according to any one of claims 3-6, wherein, The second STA is associated with the second AP.

8. The method according to any one of claims 3-7, wherein, The second truncated frame is used to reset the second basic NAV of the third STA.

9. The method according to claim 8, wherein, The second basic NAV of the third STA is set by the first frame.

10. The method of claim 8, further comprising: During the portion of the TXOP shared by the second AP and the first AP, the first AP transmits the third frame to the first STA.

11. The method according to claim 10, wherein, The third frame includes the trigger frame.

12. The method according to any one of claims 10-11, wherein, The second basic NAV of the third STA is set by the third frame.

13. The method according to any one of claims 2-12, wherein, The second truncated frame includes a contention-free end (CF-End) frame.

14. The method according to claim 13, wherein, The CF-End frame includes an indication of the transmitter address (TA) of the first AP.

15. The method according to claim 8, wherein, The third STA is associated with the second AP.

16. The method according to claim 8, wherein, The third STA includes the second AP.

17. The method according to any one of claims 2-16, wherein, The first frame includes a data frame.

18. The method according to claim 17, wherein, The data frame includes a buffer status report (BSR) indicating that the first STA does not have buffered data for transmission to the first AP.

19. The method of claim 17, wherein, The data frame includes a More Data (MD) field, which indicates that the first STA does not have buffered data for transmission to the first AP.

20. The method according to any one of claims 2-19, wherein, The second frame triggers the transmission of the first truncated frame by the first STA during the short inter-frame interval (SIFS) following the reception of the second frame.

21. The method according to any one of claims 2-20, wherein, Transmitting the second truncated frame includes transmitting the second truncated frame concurrently with the transmission of the first truncated frame by the first STA.

22. The method according to any one of claims 2-20, wherein, Transmitting the second truncated frame includes transmitting the second truncated frame simultaneously with the transmission of the first truncated frame by the first STA.

23. The method according to any one of claims 2-20, wherein, Transmitting the second truncated frame includes transmitting the second truncated frame during a short inter-frame interval (SIFS) following the second frame.

24. The method according to any one of claims 2-20, wherein, Transmitting the second truncated frame includes transmitting the second truncated frame during a time period that overlaps with the time period during which the first truncated frame is transmitted by the first STA.

25. The method according to any one of claims 2-20, wherein, Transmitting the second truncated frame includes transmitting the second truncated frame during a short inter-frame interval (SIFS) following the transmission of the first truncated frame by the first STA.

26. The method according to any one of claims 2-20, wherein, Transmitting the second truncated frame includes transmitting the second truncated frame before the first truncated frame is transmitted by the first STA.

27. The method according to claim 26, wherein, Transmitting the second truncated frame includes transmitting the second truncated frame during a short inter-frame interval (SIFS) prior to the transmission of the first truncated frame by the first STA.

28. The method of claim 27, further comprising: Transmit a block acknowledgment (BA) frame before transmitting the second truncated frame.

29. The method according to claim 28, wherein, The second truncated frame is aggregated into the BA frame.

30. A method comprising: During a portion of the transmission opportunity (TXOP) shared by the second access point (AP) and the first AP, the first station (STA) receives the first frame from the first AP; The first STA transmits a second frame to the first AP in response to the first frame, wherein the second frame indicates whether the first STA has buffered data for transmission to the first AP; The first STA receives a third frame from the first AP, and the third frame triggers the first STA to transmit a first truncated frame to reset the first basic network allocation vector (NAV) of the second STA; and The first truncated frame is transmitted by the first STA.

31. A method comprising: During a portion of a transmission opportunity (TXOP) shared by the second access point (AP) and the first AP, the first station (STA) transmits a first frame to the first AP, wherein the first frame indicates whether the first STA has buffered data for transmission to the first AP; The first STA receives a second frame from the first AP, and the second frame triggers the first STA to transmit a first truncated frame.

32. The method of claim 31, further comprising: The first truncated frame is transmitted by the first STA.

33. The method according to any one of claims 31-32, wherein, The first truncated frame is used to reset the first basic network allocation vector (NAV) of the second STA.

34. The method according to claim 33, wherein, The first basic NAV of the second STA is set by the first frame.

35. The method according to any one of claims 31-34, wherein, The first truncated frame includes a contention-free end (CF-End) frame.

36. The method according to claim 35, wherein, The CF-End frame includes an indication of the transmitter address (TA) of the first AP.

37. The method according to any one of claims 34-35, wherein, The second STA is associated with the second AP.

38. The method according to any one of claims 31-37, further comprising: During the portion of the TXOP shared by the second AP and the first AP, the first STA receives the third frame from the first AP.

39. The method according to claim 38, wherein, The third frame includes the trigger frame.

40. The method according to any one of claims 38-39, wherein, The third frame sets the second basic NAV of the third STA.

41. The method according to claim 40, wherein, The third STA is associated with the second AP.

42. The method according to claim 40, wherein, The third STA includes the second AP.

43. The method according to any one of claims 31-42, wherein, The first frame includes a data frame.

44. The method according to claim 43, wherein, The data frame includes a buffer status report (BSR) indicating that the first STA does not have buffered data for transmission to the first AP.

45. The method according to claim 44, wherein, The data frame includes a More Data (MD) field, which indicates that the first STA does not have buffered data for transmission to the first AP.

46. ​​The method according to any one of claims 31-45, wherein, The second frame triggers the transmission of the first truncated frame by the first STA during the short inter-frame interval (SIFS) following the reception of the second frame.

47. The method according to any one of claims 31-45, wherein, The first AP transmits a second truncated frame, wherein transmitting the first truncated frame includes transmitting the first truncated frame after the second truncated frame.

48. The method according to any one of claims 31-45, wherein, The first AP transmits a second truncated frame, wherein transmitting the first truncated frame includes transmitting the first truncated frame during a short inter-frame interval (SIFS) following the second truncated frame.

49. A computer program product that can be stored on a computer-readable medium and is configured to perform the method according to any one of claims 1 to 48 when run on a computer.

50. A device arranged to function in an access point (AP) of a wireless network, said device being arranged to: The first frame is transmitted to the first station (STA) during a portion of the transmission opportunity (TXOP) shared by the second AP and the first AP; Receive the second frame obtained from the first frame in response to the first frame from the first STA; Based on the second frame indicating that the first STA does not have buffered data for transmission to the device, perform the following operations: A third frame is transmitted to the first STA, the third frame triggering the transmission of a first truncated frame by the first STA to reset the first basic network allocation vector (NAV) of the second STA; and Transmit a second truncated frame to reset the second basic NAV of the third STA.

51. A device arranged to function in an access point (AP) of a wireless network, said device being arranged to: During a portion of the transmission opportunity (TXOP) shared by the second AP and the first AP, the first frame is received from the first station (STA); Based on the first frame indicating that the first STA does not have buffered data for transmission to the device, perform the following operations: The second frame is transmitted to the first STA, and the second frame triggers the transmission of the first truncated frame by the first STA. and Transmit the second truncated frame.

52. A device arranged to function in a station (STA) of a wireless network, said device being arranged to: During a portion of the transmission opportunity (TXOP) shared by the second access point (AP) and the first AP, the first frame is received from the first AP; The first AP is transmitted a second frame obtained in response to the first frame, wherein... The second frame indicates whether the first STA has buffered data for transmission to the first AP; A third frame is received from the first AP, the third frame triggering the transmission of a first truncated frame by the first STA to reset the first basic network allocation vector (NAV) of the second STA; and Transmit the first truncated frame.

53. A device arranged to function in a station (STA) of a wireless network, said device being arranged to: During a portion of the transmission opportunity (TXOP) shared by the second access point (AP) and the first AP, the first frame is transmitted to the first AP, wherein, The first frame indicates whether the first STA has buffered data for transmission to the first AP; The second frame is received from the first AP, and the second frame triggers the transmission of the first truncated frame by the first STA.

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