Uplink transmit power reporting

Abstract

An access point (AP) transmits, to a station (STA), a first frame indicating a first transmit power level for the STA. The AP transmits, to the STA, a trigger frame indicating: a second transmit power level used by the AP to transmit the trigger frame, and a target receive power level, at the AP, of a second frame. The AP receives, from the STA, the second frame in response to the trigger frame. Based on a third transmit power level exceeding the first transmit power level, the second frame indicates: the third transmit power level exceeding the first transmit power level, wherein the third transmit power level is based on the second transmit power level and the target receive power level, and a difference between the third transmit power level and the first transmit power level.

Description

Docket No.: 24-3038PCTTITLEUplink Transmit Power ReportingCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 686,906, filed August 26,2024, which is hereby incorporated by reference in its entirety.BRIEF DESCRIPTION OF THE DRAWINGS

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

[0003] FIG. 1 illustrates example wireless communication networks in which embodiments of the present disclosure may be implemented.

[0004] FIG. 2 is a block diagram illustrating example implementations of a station (STA) and an access point (AP).

[0005] FIG. 3 illustrates an example format of a physical layer (PHY) protocol data unit (PPDU).

[0006] FIG. 4 illustrates an example of a Medium Access Control (MAC) frame format.

[0007] FIG. 5 illustrates an example of a transmit power (TP) envelope element.

[0008] FIG. 6 illustrates an example control frame which may be used as a trigger frame.

[0009] FIG. 7 illustrates an example data frame which may be used as a quality of service (QoS) null frame.

[0010] FIG. 8 shows an example that illustrates use of a trigger based (TB) PPDU.

[0011] FIG. 9 illustrates an example of uplink (UL) TP headroom reporting in the presence of an uplink transmit power constraint due to the STA.

[0012] FIG. 10 illustrates an example of UL TP headroom reporting in the presence of an uplink transmit power constraint due to a local maximum TP (local max TP).

[0013] FIG. 11 illustrates an example for reporting zero UL TP headroom due to a local max TP.

[0014] FIG. 12 illustrates an example that highlights a problem that may arise in reporting zero UL TP headroom due to a local max TP.

[0015] FIG. 13 illustrates an example of UL TP headroom reporting according to an embodiment.

[0016] FIG. 14 illustrates enhanced UPH control for UL TP headroom reporting according to an embodiment.

[0017] FIG. 15 illustrates a further example of enhanced UPH control for UL TP headroom reporting according to an embodiment.

[0018] FIG. 16 illustrates another example of enhanced UPH control for UL TP headroom reporting according to an embodiment.

[0019] FIG. 17 illustrates an example process according to an embodiment of the present disclosure.

[0020] FIG. 18 illustrates an example process according to an embodiment of the present disclosure.DETAILED DESCRIPTIONDocket No.: 24-3038PCT

[0021] In the present disclosure, various embodiments are presented as examples of how the disclosed techniques may be implemented and / or how the disclosed techniques may be practiced in environments and scenarios. It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the scope. After reading the description, it will be apparent to one skilled in the relevant art how to implement alternative embodiments. The present embodiments may not be limited by any of the described exemplary embodiments. The embodiments of the present disclosure will be described with reference to the accompanying drawings. Limitations, features, and / or elements from the disclosed example embodiments may be combined to create further embodiments within the scope of the disclosure. Any figures which highlight the functionality and advantages, are presented for example purposes only. The disclosed architecture is sufficiently flexible and configurable, such that it may be utilized in ways other than that shown. For example, the actions listed in any flowchart may be re-ordered or only optionally used in some embodiments.

[0022] Embodiments may be configured to operate as needed. The disclosed mechanism may be performed when certain criteria are met, for example, in a station, an access point, a radio environment, a network, a combination of the above, and / or the like. Example criteria may be based, at least in part, on for example, wireless device or network node configurations, traffic load, initial system set up, packet sizes, traffic characteristics, a combination of the above, and / or the like. When the one or more criteria are met, various example embodiments may be applied. Therefore, it may be possible to implement example embodiments that selectively implement disclosed protocols.

[0023] In this disclosure, “a” and “an" and similar phrases are to be interpreted as “at least one” and “one or more.” Similarly, any term that ends with the suffix “(s)” is to be interpreted as “at least one” and “one or more." In this disclosure, the term “may” is to be interpreted as “may, for example.” In other words, the term “may” is indicative that the phrase following the term “may" is an example of one of a multitude of suitable possibilities that may, or may not, be employed by one or more of the various embodiments. The terms “comprises” and “consists of', as used herein, enumerate one or more components of the element being described. The term “comprises” is interchangeable with “includes" and does not exclude unenumerated components from being included in the element being described. By contrast, “consists of' provides a complete enumeration of the one or more components of the element being described. The term “based on”, as used herein, may be interpreted as “based at least in part on” rather than, for example, “based solely on”. The term “and / or” as used herein represents any possible combination of enumerated elements. For example, “A, B, and / or C” may represent A; B; C; A and B; A and C; B and C; or A, B, and C.

[0024] If A and B are sets and every element of A is an element of B, A is called a subset of B. In this specification, only non-empty sets and subsets are considered. For example, possible subsets of B = {STA1 , STA2} are: {STA1 }, {STA2}, and {STA1 , STA2}. The phrase “based on” (or equally “based at least on”) is indicative that the phrase following the term “based on” is an example of one of a multitude of suitableDocket No.: 24-3038PCT possibilities that may, or may not, be employed to one or more of the various embodiments. The phrase "in response to" (or equally “in response at least to”) is indicative that the phrase following the phrase “in response to” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments. The phrase “depending on” (or equally “depending at least to”) is indicative that the phrase following the phrase “depending on" is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments. The phrase “employing / using” (or equally “employing / using at least”) is indicative that the phrase following the phrase “employing / using” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments.

[0025] The term configured may relate to the capacity of a device whether the device is in an operational or non-operational state. Configured may refer to specific settings in a device that effect the operational characteristics of the device whether the device is in an operational or non-operational state. In other words, the hardware, software, firmware, registers, memory values, and / or the like may be “configured” within a device, whether the device is in an operational or nonoperational state, to provide the device with specific characteristics. Terms such as “a control message to cause in a device" may mean that a control message has parameters that may be used to configure specific characteristics or may be used to implement certain actions in the device, whether the device is in an operational or non-operational state.

[0026] In this disclosure, parameters (or equally called, fields, or Information elements: lEs) may comprise one or more information objects, and an information object may comprise one or more other objects. For example, if parameter (IE) N comprises parameter (IE) M, and parameter (IE) M comprises parameter (IE) K, and parameter (IE) K comprises parameter (information element) J. Then, for example, N comprises K, and N comprises J. In an example embodiment, when one or more messages / frames comprise a plurality of parameters, it implies that a parameter in the plurality of parameters is in at least one of the one or more messages / frames but does not have to be in each of the one or more messages / frames.

[0027] Many features presented are described as being optional through the use of “may” or the use of parentheses. For the sake of brevity and legibility, the present disclosure does not explicitly recite each and every permutation that may be obtained by choosing from the set of optional features. The present disclosure is to be interpreted as explicitly disclosing all such permutations. For example, a system described as having three optional features may be embodied in seven ways, namely with just one of the three possible features, with any two of the three possible features or with three of the three possible features

[0028] Many of the elements described in the disclosed embodiments may be implemented as modules. A module is defined here as an element that performs a defined function and has a defined interface to other elements. The modules described in this disclosure may be implemented in hardware, software in combination with hardware, firmware, wetware (e.g. hardware with a biological element) or a combination thereof, which may be behaviorally equivalent. For example, modules may be implemented as a softwareDocket No.: 24-3038PCT routine written in a computer language configured to be executed by a hardware machine (such as C, C++, Fortran, Java, Basic, Matlab or the like) or a modeling / simulation program such as Simulink, Stateflow, GNU Octave, or LabVIEWMathScript. It may be possible to implement modules using physical hardware that incorporates discrete or programmable analog, digital and / or quantum hardware. Examples of programmable hardware comprise: computers, microcontrollers, microprocessors, application-specific integrated circuits (ASICs); field programmable gate arrays (FPGAs); and complex programmable logic devices (CPLDs). Computers, microcontrollers and microprocessors are programmed using languages such as assembly, C, C++ or the like. FPGAs, ASICs and CPLDs are often programmed using hardware description languages (HDL) such as VHSIC hardware description language (VHDL) or Verilog that configure connections between internal hardware modules with lesser functionality on a programmable device. The mentioned technologies are often used in combination to achieve the result of a functional module.

[0029] FIG. 1 illustrates example wireless communication networks in which embodiments of the present disclosure may be implemented.

[0030] As shown in FIG. 1 , the example wireless communication networks may include an Institute of Electrical and Electronic Engineers (IEEE) 802.11 (WLAN) infra-structure network 102. WLAN infra-structure network 102 may include one or more basic service sets (BSSs) 1 10 and 120 and a distribution system (DS) 130.

[0031] BSS 110-1 and 110-2 each includes a set of an access point (AP or AP STA) and at least one station (STA or non-AP STA). For example, BSS 110-1 includes an AP 104-1 and a STA 106-1 , and BSS 1 10-2 includes an AP 104-2 and STAs 106-2 and 106-3. The AP and the at least one STA in a BSS perform an association procedure to communicate with each other.

[0032] DS 130 may be configured to connect BSS 110-1 and BSS 110-2. As such, DS 130 may enable an extended service set (ESS) 150. Within ESS 150, APs 104-1 and 104-2 are connected via DS 130 and may have the same service set identification (SSID).

[0033] WLAN infra-structure network 102 may be coupled to one or more external networks. For example, as shown in FIG. 1 , WLAN infra-structure network 102 may be connected to another network 108 (e.g., 802.X) via a portal 140. Portal 140 may function as a bridge connecting DS 130 of WLAN infra-structure network 102 with the other network 108.

[0034] The example wireless communication networks illustrated in FIG. 1 may further include one or more ad-hoc networks or independent BSSs (IBSSs). An ad-hoc network or IBSS is a network that includes a plurality of STAs that are within communication range of each other. The plurality of STAs are configured so that they may communicate with each other using direct peer-to-peer communication (i.e., not via an AP).

[0035] For example, in FIG. 1 , STAs 106-4, 106-5, and 106-6 may be configured to form a first IBSS 112- 1. Similarly, STAs 106-7 and 106-8 may be configured to form a second IBSS 112-2. Since an IBSS doesDocket No.: 24-3038PCT not include an AP, it does not include a centralized management entity. Rather, STAs within an IBSS are managed in a distributed manner. STAs forming an IBSS may be fixed or mobile.

[0036] A STA as a predetermined functional medium may include a medium access control (MAC) layer that complies with an IEEE 802.11 standard. A physical layer interface for a radio medium may be used among the APs and the non-AP stations (STAs). The STA may also be referred to using various other terms, including mobile terminal, wireless device, wireless transmit / receive unit (WTRU), user equipment (UE), mobile station (MS), mobile subscriber unit, or user. For example, the term "user” may be used to denote a STA participating in uplink Multi-user Multiple Input, Multiple Output (MU MIMO) and / or uplink Orthogonal Frequency Division Multiple Access (OFDMA) transmission.

[0037] A physical layer (PHY) protocol data unit (PPDU) may be a composite structure that includes a PHY preamble and a payload in the form of a PHY Convergence Protocol (PLCP) service data unit (PSDU). For example, the PSDU may include a PLCP preamble and header and / or one or more MAC protocol data units (MPDUs). The information provided in the PHY preamble may be used by a receiving device to decode the subsequent data in the PSDU. In instances in which PPDUs are transmitted over a bonded channel (channel formed through channel bonding), the preamble fields may be duplicated and transmitted in each of the multiple component channels. The PHY preamble may include both a legacy portion (or "legacy preamble”) and a non-legacy portion (or "non-legacy preamble”). The legacy preamble may be used for packet detection, automatic gain control and channel estimation, among other uses. The legacy preamble also may generally be used to maintain compatibility with legacy devices. The format of, coding of, and information provided in the non-legacy portion of the preamble is based on the particular IEEE 802.1 1 protocol to be used to transmit the payload.

[0038] A frequency band may include one or more sub-bands or frequency channels. For example, PPDUs conforming to the IEEE 802.11 n, 802.11ac, 802.11 ax and / or 802.11 be standard amendments may be transmitted over the 2.4 GHz, 5 GHz, and / or 6 GHz bands, each of which may be divided into multiple 20 MHz channels. The PPDUs may be transmitted over a physical channel having a minimum bandwidth of 20 MHz. Larger channels may be formed through channel bonding. For example, PPDUs may be transmitted over physical channels having bandwidths of 40 MHz, 80 MHz, 160 MHz, or 520 MHz by bonding together multiple 20 MHz channels.

[0039] FIG. 2 is a block diagram illustrating example implementations of a STA 210 and an AP 260. As shown in FIG. 2, STA 210 may include at least one processor 220, a memory 230, and at least one transceiver 240. AP 260 may include at least one processor 270, a memory 280, and at least one transceiver 290. Processor 220 / 270 may be operatively connected to memory 230 / 280 and / or to transceiver 240 / 290.

[0040] Processor 220 / 270 may implement functions of the PHY layer, the MAC layer, and / or the logical link control (LLC) layer of the corresponding device (STA 210 or AP 260). Processor 220 / 270 may include one or more processors and / or one or more controllers. The one or more processors and / or one or moreDocket No.: 24-3038PCT controllers may comprise, for example, a general-purpose processor, a digital signal processor (DSP), a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a logic circuit, or a chipset, for example.

[0041] Memory 230 / 280 may include a read-only memory (ROM), a random-access memory (RAM), a flash memory, a memory card, a storage medium, and / or other storage unit. Memory 230 / 280 may comprise one or more non-transitory computer readable mediums. Memory 230 / 280 may store computer program instructions or code that may be executed by processor 220 / 270 to carry out one or more of the operations / embodiments discussed in the present application. Memory 230 / 280 may be implemented (or positioned) within processor 220 / 270 or external to processor 220 / 270. Memory 230 / 280 may be operatively connected to processor 220 / 270 via various means known in the art.

[0042] Transceiver 240 / 290 may be configured to transmit / receive radio signals. In an embodiment, transceiver 240 / 290 may implement a PHY layer of the corresponding device (STA 210 or AP 260). In an embodiment, STA 210 and / or AP 260 may be a multi-link device (MLD), that is a device capable of operating over multiple links as defined by the IEEE 802.11 standard. As such, STA 210 and / or AP 260 may each implement multiple PHY layers. The multiple PHY layers may be implemented using one or more of transceivers 240 / 290.

[0043] FIG. 3 illustrates an example format of a PPDU 300. As shown, the PPDU 300 may include a PHY preamble, a PHY header, a PSDU, and tail and padding bits.

[0044] The PSDU may include one or more MPDUs, such as a QoS data frame, a MAC management protocol data unit (MMPDU), a MAC control frame, or a QoS null frame. In the case of an MPDU carrying a QoS data frame, the frame body of the MPDU may include a MAC service data unit (MSDU) or an aggregated MSDU (A-MSDU).

[0045] By default, MSDU transport is on a best-effort basis. That is, there is no guarantee that a transmitted MSDU will be delivered successfully. However, the QoS facility uses a traffic identifier (TID) to specify differentiated services on a per-MSDU basis.

[0046] A STA may differentiate MSDU delivery according to designated traffic category (TC) or traffic stream (TS) of individual MSDUs. The MAC sublayer entities determine a user priority (UP) for an MSDU based on a TID value provided with the MSDU. The QoS facility supports eight UP values. The UP values range from 0 to 7 and form an ordered sequence of priorities, with 1 being the lowest value, 7 the highest value, and 0 falling between 2 and 3.

[0047] An MSDU with a particular UP is said to belong to a traffic category with that UP. The UP may be provided with each MSDU at the medium access control service access point (MAC SAP) directly in a UP parameter. An A-MPDU may include MPDUs with different TID values.

[0048] A STA may deliver buffer status reports (BSRs) to assist an AP in allocating UL MU resources. The STA may either implicitly deliver BSRs in the QoS control field or BSR control subfield of any frameDocket No.: 24-3038PCT transmitted to the AP (unsolicited BSR) or explicitly deliver BSRs in a frame sent to the AP in response to a BSRP Trigger frame (solicited BSR).

[0049] The buffer status reported in the QoS control field includes a queue size value for a given TID. The buffer status reported in the BSR control field includes an ACI bitmap, delta TID, a high priority AC, and two queue sizes.

[0050] A STA may report buffer status to the AP, in the QoS control field, of transmitted QoS null frames and QoS data frames and, in the BSR control subfield (if present), of transmitted QoS null frames, QoS data frames, and management frames as defined below.

[0051] The STA may report the queue size for a given TID in the queue size subfield of the QoS control field of transmitted QoS data frames or QoS null frames; the STA may set the queue size subfield to 255 to indicate an unknown / unspecified queue size for that TID. The STA may aggregate multiple QoS data frames or QoS null frames in an A-MPDU to report the queue size for different TIDs.

[0052] The STA may report buffer status in the BSR control subfield of transmitted frames if the AP has indicated its support for receiving the BSR control subfield.

[0053] A High-Efficiency (HE) STA may report the queue size for a preferred AC, indicated by the ACI high subfield, in the queue size high subfield of the BSR control subfield. The STA may set the queue size high subfield to 255 to indicate an unknown / unspecified queue size for that AC.

[0054] A HE STA may report the queue size for ACs indicated by the ACI bitmap subfield in the queue size all subfield of the BSR control subfield. The STA may set the queue size all subfield to 255 to indicate an unknown / unspecified BSR for those ACs.

[0055] FIG. 4 illustrates an example format of a MAC frame 400. In operation, a STA may construct a subset of MAC frames for transmission and may decode a subset of received MAC frames upon validation. The particular subsets of frames that a STA may construct and / or decode may be determined by the functions supported by the STA. A STA may validate a received MAC frame using the frame check sequence (FCS) contained in the frame and may interpret certain fields from the MAC headers of all frames.

[0056] As shown in FIG. 4, a MAC frame 400 includes a MAC header, a variable length frame body, and a frame check sequence (FCS).

[0057] The MAC header includes a frame control field, an optional duration / ID field, address fields, an optional sequence control field, an optional QoS control field, and an optional HT control field.

[0058] The frame control field includes the following subfields: protocol version, type, subtype, "To DS”, “From DS”, “More Fragments”, retry, power management, “More Data , protected frame, and +HTC.

[0059] The protocol version subfield is invariant in size and placement across all revisions of the IEEE 802.11 standard. The value of the protocol version subfield is 0 for MAC frames.Docket No.: 24-3038PCT

[0060] The type and subtype subfields together identify the function of the MAC frame 400. There are three frame types: control, data, and management. Each of the frame types has several defined subtypes. Bits within the subtype subfield are used to indicate a specific modification of the basic data frame (subtype 0). For example, in data frames, the most significant bit (MSB) of the subtype subfield, bit 7 (B7) of the frame control field, is defined as the QoS subfield. When the QoS subfield is set to 1 , it indicates a QoS data frame, which is a data frame that contains a QoS control field in its MAC header. The second MSB of the subtype field, bit 6 (B6) of the frame control field, when set to 1 in data subtypes, indicates a data frame that contain no frame body field.

[0061] The “To DS” subfield indicates whether a data frame is destined to the distribution system (DS). The “From DS” subfield indicates whether a data frame originates from the DS.

[0062] The “More Fragments” subfield is set to 1 in all data or management frames that have another fragment to follow the MSDU or MMPDU carried by the MAC frame. The “More Fragments” subfield is set to 0 in all other frames in which the “More Fragments” subfield is present.

[0063] The retry subfield is set to 1 in any data or management frame that is a retransmission of an earlier frame. It is set to 0 in all other frames in which the retry subfield is present. A receiving STA uses this indication to aid it in the process of eliminating duplicate frames. These rules do not apply for frames sent by a STA under a block agreement.

[0064] The power management subfield is used to indicate the power management mode of a STA.

[0065] The “More Data” subfield indicates to a STA in power save (PS) mode that bufferable units (BUs) are buffered for that STA at the AP. The “More Data" subfield is valid in individually addressed data or management frames transmitted by an AP to a STA in PS mode. The “More Data” subfield is set to 1 to indicate that at least one additional buffered BU is present for the STA.

[0066] The protected frame subfield is set to 1 if the frame body field contains information that has been processed by a cryptographic encapsulation algorithm.

[0067] The +HTC subfield indicates that the MAC frame contains an HT control field.

[0068] The duration / ID field of the MAC header indicates various contents depending on the frame type and subtype and the QoS capabilities of the sending STA. For example, in control frames of the power save poll (PS-Poll) subtype, the duration / ID field carries an association identifier (AID) of the STA that transmitted the frame in the 14 least significant bits (LSB), with the 2 most significant bits (MSB) set to 1 . In other frames sent by STAs, the duration / ID field contains a duration value (in microseconds) which is used by a recipient to update a network allocation vector (NAV). The NAV is a counter that indicates to a STA an amount of time during which the STA must defer from accessing the shared medium.

[0069] Up to four address fields may be present in the MAC frame format. The address fields are used to indicate the basic service set identifier (BSSID), source address (SA), destination address (DA), transmitting address (TA), and receiving address (RA). Certain frames may not contain some of the address fields. CertainDocket No.: 24-3038PCT address field usage may be specified by the relative position of the address field (1-4) within the MAC header, independent of the type of address present in that field . Specifically, the address 1 field always identifies the intended receiver(s) of the frame, and the address 2 field, where present, always identifies the transmitter of the frame.

[0070] The sequence control field includes two subfields, a sequence number subfield and a fragment number subfield. The sequence number subfield in data frames indicates the sequence number of the MSDU (if not in an A-MSDU) or A-MSDU. The sequence number subfield in management frames indicates the sequence number of the frame. The fragment number subfield indicates the number of each fragment of an MSDU or MMPDU. The fragment number is set to 0 in the first or only fragment of an MSDU or MMPDU and is incremented by one for each successive fragment of that MSDU or MMPDU. The fragment number is set to 0 in a MPDU containing an A-MSDU, or in an MPDU containing an MSDU or MMPDU that is not fragmented. The fragment number remains constant in all retransmissions of the fragment.

[0071] The QoS control field identifies the traffic category (TC) or traffic stream (TS) to which the MAC frame belongs. The QoS control field may also indicate various other QoS related, A-MSDU related, and mesh- related information about the frame. This information can vary by frame type, frame subtype, and type of transmitting STA. The QoS control field is present in all data frames in which the QoS subfield of the subtype subfield is equal to 1.

[0072] The HT control field is present in QoS data, QoS null, and management frames as determined by the +HTC subfield of the frame control field.

[0073] The frame body field is a variable length field that contains information specific to individual frame types and subtypes. The frame body may include one or more MSDUs or MMPDUs. The minimum length of the frame body is 0 octets.

[0074] The FCS field contains a 32-bit Cyclic Redundancy Check (CRC) code. The FCS field value is calculated over all of the fields of the MAC header and the frame body field.

[0075] FIG. 5 illustrates an example of a transmit power envelope element 500. An AP or a group of APs may indicate a local transmit power constraint for each of their clients (e.g., for controlling spatial reuse properties of a network) using transmit power envelope element 500. For example, an AP may send transmit power envelope element 500 in a beacon, association response, or probe response frames to its clients. Transmit power envelope element 500 can convey to the clients the local or regulatory maximum transmit powers for various transmission bandwidths or channels within the bandwidth of the BSS. Low client transmit power typically results in lower reliability or lower throughput for the respective clients, but allows other clients from other BSSs to access the channel in parallel. Higher client transmit power will typically result in higher reliability and / or higher throughput for the respective clients, but can cause a busy indication (e.g., a clear channel assessment (CCA) BUSY indication) to other STAs in other BSSs, resulting in fewer parallel transmissions.Docket No.: 24-3038PCT

[0076] As shown in FIG. 5, transmit power envelope element 500 includes an Element ID field, a Length Field, a Transmit Power Information field, and a Maximum Transmit Power field. The Element ID field includes a value that identifies element 500 as a transmit power envelope element The Length field indicates a length of transmit power envelope element 500. The transmit power information field includes a maximum transmit power count subfield, a maximum transmit power interpretation subfield, and a maximum transmit power category subfield. As discussed further below, the maximum transmit power count subfield indicates a number of subfields in the maximum transmit power field. The maximum transmit power interpretation subfield indicates the contents of the maximum transmit power field. For example, different values in the maximum transmit power interpretation subfield indicate different interpretations for the contents of the maximum transmit power field. Values of 0 or 1 in the maximum transmit power interpretation subfield can indicate a local maximum transmit power setting. For example, a value of 0 can indicate that the maximum transmit power field describes local effective isotropic radiated power (El RP), while a value of 1 can indicate that the maximum transmit power field describes local EIRP power spectral density (PSD).

[0077] Values of 2, 3, 4, or 5 in the maximum transmit power interpretation subfield can indicate a regulatory maximum transmit power setting. For example, a value of 2 in the maximum transmit power interpretation subfield can indicate that the maximum transmit power field describes regulatory client EIRP, while a value of 3 in the maximum transmit power interpretation subfield can indicate that the maximum transmit power field describes regulatory client EIRP PSD. A value of 4 in the maximum transmit power interpretation subfield can indicate that the maximum transmit power field describes additional regulatory client EIRP, while a value of 5 in the maximum transmit power interpretation subfield can indicate that the maximum transmit power field describes additional regulatory client EIRP PSD. In the illustrated example, the values of 6 and 7 are reserved.

[0078] The maximum transmit power category subfield can indicate a category for which the maximum transmit powers apply. A value of 0 can indicate the default category, while a value of 1 can indicate a subordinate device (e.g. , a device that operates under the control of an AP (e.g., an indoor AP) with additional requirements specified by the regulatory domain in which the AP is operating). In this example values 2-3, for the maximum transmit power category subfield, are reserved.

[0079] If the maximum transmit power interpretation subfield Is O, 2 or 4 (e.g. indicating EIRP), the maximum transmit power count subfield can indicate a number of subfields in the maximum transmit power field (e.g., subfields indicating the maximum transmit power for X MHz where / equals any of 20, 40, 80, or 160 / 80+80) minus one. For example, in this scenario a maximum transmit power count subfield value of 0 can indicate maximum transmit power is present for 20 MHz, a maximum transmit power count subfield value of 1 can indicate maximum transmit power is present for 20 MHz and 40 MHz, a maximum transmit power count subfield value of 2 can indicate maximum transmit power is present for 20 MHz, 40 MHz, and 80 MHz, and a maximum transmit power count subfield value of 3 can indicate maximum transmit power is present for 20Docket No.: 24-3038PCTMHz, 40 MHz, 80 MHz, and 160 / 80+80 MHz. In these examples a first octet of the maximum transmit power field can indicate maximum transmit power for 20 MHz, a second octet can indicate maximum transmit power for 40 MHz, a third octet can indicate maximum transmit power for 80 MHz, and a fourth octet can indicate maximum transmit power for 160 / 80+80 MHz.

[0080] Maximum transmit power for X MHz fields (e.g., where X = 20, 40, 80, or 160 / 80+80) can define the local maximum transmit power limit of X MHz PPDUs, except for an HE TB PPDU where X MHz is the bandwidth of the pre-HE modulated fields of the HE TB PPDU transmitted by a STA. Each maximum transmit power for X MHz field can be encoded, for example, as an 8-bit 2s complement signed integer (e.g., in the range -64 dBm to 63 dBm with a 0.5 dB step). Setting this field to 63.5 dBm can indicate 63.5 dBm or higher (e.g., no local maximum transmit power constraint).

[0081] If the maximum transmit power interpretation subfield is 1 , 3 or 5 (e.g., indicating EIRP PSD), the maximum transmit power field can have a format in which a first octet indicates a maximum transmit PSD 1 , and subsequent octets (e.g., 2-W) indicate maximum transmit power for a respective corresponding PSD (e.g., a PSD 2-N). In this scenario the maximum transmit power count subfield can determine the value of an integer N according to defined rules. For example, if N is 0, then the maximum transmit power field can contain one maximum transmit PSD subfield that represents the maximum transmit PSD for a PPDU of any bandwidth within the BSS bandwidth. If N is greater than 0, then the maximum transmit power field can have N octets, with N representing the number of 20 MHz channels for which a maximum transmit PSD is indicated. Thehoctet (e.g., where Xequals an integer ranging from 1 to N) of the maximum transmit power field can be the maximum transmit PSD subfield, which can indicate the maximum transmit PSD for the Xh20 MHz channel.

[0082] If the BSS bandwidth is 20, 40, 80, or 160 MHz, then the maximum transmit PSD 1- / V subfields can correspond to 20 MHz channels (e.g., from lowest to highest frequency, respectively), within the indicated bandwidth. If N is equal to 1 , 2, 4, or 8 for 20, 40, 80, or 160 MHz BSS bandwidth, respectively, the indicated bandwidth can be the BSS bandwidth. If N is greater than 0 and less than 2, 4, or 8 for 40, 80, or 160 MHz BSS bandwidth, respectively, then the indicated bandwidth can be the primary 20 MHz, primary 40 MHz, or primary 80 MHz channel for N equal to 1 , 2, or 4, respectively. If N is greater than 1 , 2, or 4 for 20, 40, or 80 MHz BSS bandwidth, respectively, then the indicated bandwidth can be wider than the BSS bandwidth. In this case, the maximum transmit PSD 1-M subfields can correspond to the 20 MHz channels (e.g., from lowest to highest frequency, respectively), within the BSS bandwidth where M is 1 , 2, or 4 for 20, 40, or 80 MHz BSS bandwidth, respectively.

[0083] If the BSS bandwidth is 80+80 MHz, N can be less than or equal to 8. If N is equal to 8 and the BSS bandwidth is 80+80 MHz, the maximum transmit PSD 1-4 subfields can correspond to the 20 MHz channels (e.g., from lowest to highest frequency, respectively), within the 80 MHz segment lower in frequency. The maximum transmit PSD 5-8 subfields can correspond to the 20 MHz channels (e.g., from lowest to highestDocket No.: 24-3038PCT frequency, respectively), within the 80 MHz segment higher in frequency. If N is greater than 0 and less than 8 for 80+80 MHz BSS bandwidth, then the bandwidth indicated by the Maximum Transmit PSD 1- / V subfields can be the primary 20 MHz, primary 40 MHz, or primary 80 MHz channel for Nequal to 1 , 2, or 4, respectively. In this case, the maximum transmit PSD 1 -N subfields correspond to 20 MHz channels (e.g ., from lowest to highest frequency, respectively, within the indicated bandwidth).

[0084] Values of the maximum transmit power count field between 5 and 7 can be reserved for future use to indicate values of N greater than 8. If N is greater than 8, the maximum transmit PSD 1 -8 subfields can correspond to the 20 MHz channels from lowest to highest frequency, respectively, within the 160 MHz channel containing the primary 20 MHz channel.

[0085] The maximum transmit PSD X subfield can be encoded as an 8-bit 2s complement signed integer. The value of -128 can indicate that the corresponding 20 MHz channel cannot be used for transmission. The value of +127 can indicate that no maximum PSD limit is specified for the corresponding 20 MHz channel. For all other values Y of the subfield (e.g., -127 to +126, inclusive), the maximum transmit PSD in the corresponding 20 MHz channel can be Y / 2 dBm / MHz (e.g., ranging from -63.5 to +63 dBm / MHz). If an allowed PSD for the Xth20 MHz channel is known with finer resolution than 20 MHz, the maximum transmit PSD X subfield is set to the lowest allowed PSD within theth20 MHz channel.

[0086] A STA may select a transmit power for transmissions in a channel using one or more constraints. For example, a STA may determine a regulatory maximum transmit power and a local maximum transmit power for a channel in the current regulatory domain using transmit power envelope element 500, among other criteria, before transmitting in the channel. An AP may use a transmit power less than or equal to the regulatory maximum transmit power level for the channel, while also meeting any regulatory mitigation requirement(s). A non-AP STA may use a transmit power less than or equal to the minimum of the local maximum transmit power level and the regulatory maximum transmit power for the channel.

[0087] FIG. 6 illustrates an example control frame which may be used as a trigger frame 600. Trigger frame 600 may be used by an AP to allocate resources for and solicit one or more TB PPDU transmissions from one or more STAs. Trigger frame 600 may also carry other information required by a responding STA to transmit a TB PPDU to the AP.

[0088] As shown in FIG. 6, trigger frame 600 includes a Frame Control field, a Duration field, a receiver address (RA) field, a transmitter address (TA) field, a Common Info field, a User Info List field, a Padding field, and an FCS field.

[0089] The Frame Control field includes the following subfields: protocol version, type, subtype, To DS, From DS, more fragments, retry, power management, more data, protected frame, and +HTC.

[0090] The Duration field indicates various contents depending on frame type and subtype and the QoS capabilities of the sending STA. For example, in control frames of the power save poll (PS-Poll) subtype, the Duration field carries an association identifier (AID) of the STA that transmitted the frame in the 14 leastDocket No.: 24-3038PCT significant bits (LSB), and the 2 most significant bits (MSB) are both set to 1 . In other frames sent by STAs, the Duration field contains a duration value (in microseconds) which is used by a recipient to update a network allocation vector (NAV)

[0091] The RA field is the address of the STA that is intended to receive the incoming transmission from the transmitting station. The TA field is the address of the STA transmitting trigger frame 600 if trigger frame 600 is addressed to STAs that belong to a single BSS. The TA field is the transmitted BSSID if trigger frame 600 is addressed to STAs from at least two different BSSs of the multiple BSSID set.

[0092] The Common Info field specifies a trigger frame type of trigger frame 600, a transmit power of trigger frame 600 in dBm, and several key parameters of a TB PPDU that is transmitted by a STA in response to trigger frame 600. The trigger frame type of a trigger frame used by an AP to receive QoS data using UL MU operation is referred to as a basic trigger frame. A non-EHT non-AP HE STA interprets the Common Info field as HE variant. A non-AP EHT STA interprets the Common Info field as HE variant if B54 and B55 in the Common Info field are equal to 1 ; and interprets the Common Info field as EHT variant otherwise. The HE variant Common Info field and the EHT variant Common Info field use the same encoding method for the Trigger Type, UL Length, More TF, CS Required, LDPC Extra Symbol Segment, AP TX Power, Pre-FEC Padding Factor, PE Disambiguity, and Trigger Dependent Common Info subfields.

[0093] The User Info List field contains zero or more User Info fields. There are three variants for the User Info field, which are the Special User Info field, the EHT variant User Info field, and the HE variant User Info field.

[0094] The Special User Info field is a User Info field that does not carry the user specific information but carries the extended common information not provided in the Common Info field. If the Special User Info field is included in the Trigger frame, then the Special User Info Field Flag subfield of the EHT variant Common Info field is set to 0, otherwise it is set to 1 . The Special User Info field is identified by an AID12 value of 2007 and is optionally present in a Trigger frame that is generated by an EHT AP. The Special User Info field, if present, is located immediately after the Common Info field of the Trigger frame and carries information for the U-SIG field of a solicited EHT TB PPDU. The PHY Version Identifier subfield indicates the PHY version of the solicited TB PPDU that is not an HE TB PPDU. The PHY Version Identifier subfield is set to 0 for EHT. Other values from 1 to 7 are reserved. The UL Bandwidth (BW) Extension subfield, together with the UL BW subfield in the Common Info field, indicates the bandwidth of the solicited TB PPDU from the addressed EHT STA (i.e , the bandwidth in the U-SIG field of the EHT TB PPDU). The EHT Spatial Reuse n subfield carries the values to be included in the corresponding Spatial Reuse n subfield in the U-SIG field of the EHT TB PPDU. The U-SIG Disregard And Validate subfield carries the values to be included in the Disregard and Validate subfields of the U-SIG field of the solicited EHT TB PPDUs. The presence and length of the Trigger Dependent User Info subfield in the Special User Info field depends on the variant of the Trigger frame.Docket No.: 24-3038PCT

[0095] The EHT variant User Info field contains a User Info field per STA addressed in trigger frame 600. The per STA User Info field includes, among others, an AID12 subfield, an RU Allocation subfield, a UL FEC Coding Type subfield, a UL extremely high throughput (EHT) modulation and coding scheme (MCS) (EHT- MCS) subfield, a Reserved subfield, a Spatial Stream (SS) Allocation / RA-RU information subfield, a UL Target Receive Power subfield, and a Power Save (PS) 160 subfield to be used by a STA in a TB PPDU transmitted in response to trigger frame 600, and a Trigger Dependent User Info subfield. The RU Allocation subfield in an EHT variant User Info field in a Trigger frame that is not an MU-RTS Trigger frame, along with the UL BW subfield in the Common Info field, the UL BW Extension subfield in the Special User Info field, and the PS160 subfield in the EHT variant User Info field, identifies the size and the location of the RU or MRU. The values of PS160 subfield and B0 of RU Allocation subfield indicate the 80 MHz frequency subblock in which the RU or MRU is located for 26-tone RU, 52-tone RU, 106-tone RU, 242-tone RU, 484-tone RU, 996-tone RU, 52+26-tone RU, and 106+26-tone RU. The values of PS160 subfield indicates the 160 MHz segment in which the RU or MRU is located for 2®96-tone RU, 996+484-tone MRU, and 996+484+242-tone MRU. The UL FEC Coding Type subfield of the User Info field indicates the code type of the solicited EHT TB PPDU. The UL FEC Coding Type subfield is set to 0 to indicate BCC and set to 1 to indicate LDPC. The UL EHT-MCS subfield of the User Info field indicates the EHT-MCS of the solicited EHT TB PPDU. The SS Allocation subfield of the EHT variant User Info field indicates the spatial streams of the solicited EHT TB PPDU. The UL Target Receive Power subfield indicates the expected receive signal power, measured at the AP’s antenna connector and averaged over the antennas, for the EHT portion of the EHT TB PPDU transmitted on the assigned RU. The Trigger Dependent User Info subfield can be used by an AP to specify a preferred access category (AC) per STA. The preferred AC sets the minimum priority AC traffic that can be sent by a participating STA. The AP determines the list of participating STAs, along with the BW, MCS, RU allocation, SS allocation, Tx power, preferred AC, and maximum duration of the TB PPDU per participating STA. The RA-RU Information subfield is reserved in the EHT variant User Info field.

[0096] The Padding field is optionally present to extend the frame length to give recipient STAs enough time to prepare a response for transmission one SIFS after the frame is received. The Padding field, if present, is at least two octets in length and is set to all 1s.

[0097] The FCS field is used by a STA to validate a received frame and to interpret certain fields from the MAC headers of a frame.

[0098] FIG. 7 illustrates an example data frame 700 which may be used as a QoS null frame. A QoS null frame refers to a QoS data frame with an empty frame body. QoS null frame includes a QoS control field and an optional HT control field which may contain a buffer status report (BSR) control subfield. A QoS null frame indicating buffer status information may be transmitted by a STA to an AP.Docket No.: 24-3038PCT

[0099] The QoS control field may include a traffic identifier (TID) subfield, an acknowledgment (Ack) policy indicator subfield, and a queue size subfield (or a transmission opportunity (TXOP) duration requested subfield).

[0100] The TID subfield identifies the TC or TS of traffic for which a TXOP is being requested, through the setting of the TXOP duration requested or queue size subfield. The encoding of the TID subfield depends on the access policy (e.g., Allowed value 0 to 7 for enhanced distributed channel access (EDCA) access policy to identify user priority for either TC or TS).

[0101] The ack policy indicator subfield, together with other information, identifies the Ack policy followed upon delivery of the MPDU (e.g., normal Ack, implicit block Ack request, no Ack, block Ack, etc.)

[0102] The queue size subfield is an 8-bit field that indicates the amount of buffered traffic for a given TC or TS at the STA for transmission to the AP identified by the receiver address of the frame containing the subfield. The queue size subfield is present in QoS null frames sent by a STA when bit 4 of the QoS control field is set to 1. The AP may use information contained in the queue size subfield to determine the TXOP duration assigned to the STA or to determine the uplink (UL) resources assigned to the STA.

[0103] In a frame sent by or to a non-high efficiency (non-HE) STA, the following rules may apply to the queue size value:

[0104] The queue size value is the approximate total size, rounded up to the nearest multiple of 256 octets and expressed in units of 256 octets, of all MSDUs and A-MSDUs buffered at the STA (excluding the MSDU or A-MSDU contained in the present QoS Data frame) in the delivery queue used for MSDUs and A-MSDUs with TID values equal to the value indicated in the TID subfield of the QoS Control field.

[0105] A queue size value of 0 is used solely to indicate the absence of any buffered traffic in the queue used for the specified TID.

[0106] A queue size value of 254 is used for all sizes greater than 64 768 octets.

[0107] A queue size value of 255 is used to indicate an unspecified or unknown size.

[0108] In a frame sent by an HE STA to an HE AP, the following rules may apply to the queue size value.

[0109] The queue size value, QS, is the approximate total size in octets, of all MSDUs and A-MSDUs buffered at the STA (including the MSDUs or A-MSDUs contained in the same PSDU as the frame containing the queue size subfield) in the delivery queue used for MSDUs and A-MSDUs with TID values equal to the value indicated in the TID subfield of the QoS control field.

[0110] The queue size subfield includes a scaling factor subfield in bits B14-B15 of the QoS control field and an unsealed value, UV, in bits B8-B13 of the QoS control field. The scaling factor subfield provides the scaling factor, SF.

[0111] A STA obtains the queue size, QS, from a received QoS control field, which contains a scaling factor, SF, and an unsealed value, UV, as follows:

[0112] QS =Docket No.: 24-3038PCT

[0113] 16 xL / V, if SF is equal to 0;

[0114] 1024 + 256 x UV, if SF is equal to 1 ;

[0115] 17408 + 2048 x L / V, if SF is equal to 2;

[0116] 148 480 + 32 768 x UV, if SF is equal to 3 and (JVis less than 62;

[0117] > 2 147 328, if SF equal to is 3 and (A / is equal to 62;

[0118] Unspecified or Unknown, if SF is equal to 3 and t / Vis equal to 63.

[0119] The TXOP duration requested subfield, which may be included instead of the queue size subfield, indicates the duration, in units of 32 microseconds (us), that the sending STA determines it needs for its next TXOP for the specified TID. The TXOP duration requested subfield is set to 0 to indicate that no TXOP is requested for the specified TID in the current service period (SP). The TXOP duration requested subfield is set to a nonzero value to indicate a requested TXOP duration in the range of 32 us to 8160 us in increments of 32 us.

[0120] The HT control field may include an aggregated control (A-Control) subfield. The A-Control subfield may include a control list subfield including one or more control subfields. A control subfield (of the one or more control subfields) may be a UL power headroom (UPH) control subfield, which as shown in FIG. 7 may include a UL Power Headroom subfield, a Minimum Transmit Power Flag subfield, and two reserved bits. The UL Power Headroom subfield may contain the UPH used for power precorrection. In an example, the UL power headroom subfield may indicate the available UPH (e.g., in units of dB), for the current MCS (e.g ., for a current HE-MCS). For example, the UL power headroom subfield can carry a value 0 to 31 that maps to 0 dB to 31 dB. The minimum transmit power flag subfield may be set to 1 to indicate that the minimum transmit power for the current MCS (e.g., HE-MCS) is reached by the STA, and may be set to 0 otherwise.

[0121] Further, a STA that transmits an HE TB PPDU may transmit the decibel value of its UL power headroom, HRSTA, in the UPH Control subfield of frames (e.g., frames that can carry an HE-variant HT Control field) carried in the HE TB PPDU (e.g., to assist in the AP’s HE-MCS selection). The UL power headroom for an assigned HE-MCS can be defined in the equation below:where Tx^ f represents the maximum UL transmit power of an HE TB PPDU with the assigned HE-MCS (e.g , after considering hardware capability, regulatory requirements, and local maximum transmit power levels, as well as non-IEEE-802.11 in-device coexistence requirements), Tx ™. represents the current UL transmit power of the HE TB PPDU for the assigned HE-MCS (e.g., determined by power control and subject to the non-AP STA's capabilities and other requirements such as power precorrection), and HRSTAis the UL power headroom, in dB, of the HE TB PPDU.

[0122] In an example, if the Minimum Transmit Power Flag subfield in the UPH Control subfield is 1 , then the non-AP STA is transmitting the HE TB PPDU at its minimum Tx ™ for the assigned HE-MCS. The ULDocket No.: 24-3038PCT power headroom may be calculated for the assigned HE-MCS and is independent of transmit operating mode (TOM) parameters provided in any operating mode (OM) control field contained in the same A-Control subfield. Further, in an example the UL power headroom is not normalized to 20 MHz bandwidth (e g., unlike the value in the AP Tx Power subfield).

[0123] As a further example, a non-AP STA may include an HE variant HT Control field containing the UPH Control subfield in frames carried in the A-MPDU of the HE TB PPDU, with the following exceptions. First, a UPH Control subfield may not be included in any frame if the remaining space in the A-MPDU, after inclusion of solicited frames that are required to be included in the A-MPDU but cannot contain an HE variant HT control field, is not sufficient to contain a frame that can be included in the AMPDU and can contain an HE variant HT control field. Second, a UPH control subfield may not be included in a frame if the frame contains control subfields other than UPH control and ONES control subfields and the remaining space in the HE variant HT control field of the frame is not sufficient to contain a UPH control subfield as well. Third, a UPH control subfield may not be included in a frame that is a control frame.

[0124] FIG. 8 shows an example 800 that illustrates use of a TB PPDU.

[0125] As shown in FIG. 8, example 800 includes an AP 802 and a plurality of STAs 804-1 to 804-8.

[0126] In an example, AP 802 may transmit TF 810 to STAs 804-1 to 804-8 to solicit UL frames from STAs 804-1 to 804-8. STAs 804-1 to 804-8 may respond simultaneously to TF 810 by each transmitting a TB PPDU 820. In an example, TB PPDU 820 may have an 80 MHz bandwidth. As shown in FIG. 8, a STA 804 may duplicate four times over frequency each of the fields L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and EHT-STF to fill out the 80 MHz bandwidth. EHT-LTFs 840 and a data field 850 of PPDU 820 may fill out the entire 80 MHz bandwidth and are not duplicated over frequency. The number of EHT-LTFs transmitted by the STA (in time) is based on the maximum number of spatial streams across all RUs contained in the TB PPDU 820. In example 800, TB PPDU 820 includes eight EHT-LTFs 840-1 to 840-8. AP 802 may acknowledge TB PPDU 820 by transmitting a multi-user block acknowledgment frame M-BA 830.

[0127] As TB PPDUs 820 transmitted by STAs 804-1 to 804-8 are transmitted simultaneously in response to TF 810, precorrection of time, frequency, sampling clock, and power (in the case of a High Efficiency (HE) TB PPDU or extremely high throughput (EHT) TB PPDU) by STAs 804-1 to 804-8 may be necessary to mitigate synchronization and interference issues at AP 802. Specifically, frequency and sampling clock precorrections are needed to prevent inter-carrier interference. Power precorrection is necessary to control interference between TB PPDUs 820.

[0128] In an implementation, TF 810 includes in a User Info field an uplink (UL) Target Receive Power subfield that indicates whether a STA among STAs 804-1 to 804-8 is to transmit TB PPDU 820 at a maximum transmit power. The maximum transmit power may correspond to the STA’s maximum transmit power for the assigned HE-MCS. The STA transmits TB PPDU 820 at the maximum transmit power when the UL TargetDocket No.: 24-3038PCTReceive Power subfield indicates that the maximum transmit power is to be used. Otherwise, the STA calculates the transmit power, Txp™, of TB PPDU 820 for the assigned HE-MCS using the equation:Tx ™ = PLDL+ TargetRxpwrwhere PLDLis the downlink pathloss and TargetRxpwris the expected receive signal power, in units of dBm, as indicated by the UL Target Receive Power subfield in the User Info field of TF 810. If the STA applies beamforming to TB PPDU 820, the STA may take into account the beamforming gain when calculating the transmit power.

[0129] In an implementation, the STA computes PLDLusing the equation:where Txp ris the AP’s transmit power, in units of dBm / 20 MHz, as indicated by an AP Tx Power subfield of a Common Info field of TF 810 and Rxpwris the receive signal power, in units of dBm / 20MHz, of TF 810 at an antenna connector of the STA. Rxpwrmay be an average of the receive signal power over the antennas on which the average PLDLis being computed.

[0130] Due to the finite accuracy of clock generating circuits of an AP and a STA, an AP and an associated STA tuned to the same carrier frequency may have errors in their generated carrier frequencies in reference to the ideal carrier frequency. When an AP receives a TB PPDU as in example 800, the AP may observe a baseband signal whose center frequency has an offset (i.e. carrier frequency offset or CFO) from the DC subcarrier. Similarly, an AP receiving the symbols of a TB PPDU sampled using its own clock may observe that the TB PPDU signal is generated at a clock offset (i.e. symbol clock offset or SCO) from its own sampling clock. Both SCO and CFO may result in receive errors when not properly mitigated. In order to limit the effects of CFO and SCO, a STA compensates for carrier frequency offset (CFO) error and symbol clock error with respect to TF 810 when TB PPDU 820 is a TB PPDU or a non-HT or non-HT duplicate PPDU with the TXVECTOR parameter TRIGGER_RESPONDING set to true. After compensation, the absolute value of residual CFO error with respect to TF 810 shall not exceed the following levels when measured at the 10% point of a complementary cumulative distribution function (CCDF) of CFO errors in Additive White Gaussian Noise (AWGN) at a received power of -60 dBm in the primary 20 MHz channel: 350 Hz for the data subcarriers of a TB PPDU; 2 kHz for a non-HT PPDU or non-HT duplicate PPDU. The residual CFO error measurement on an HE TB PPDU shall be made after the HE-SIG-A field. The residual CFO error measurement on an EHT TB PPDU shall be made after the U-SIG field. The residual CFO error measurement on a non-HT or non-HT duplicate PPDU shall be made after the L-STF field. The symbol clock error shall be compensated by the same ppm amount as the CFO error.

[0131] In a trigger based transmission, an AP transmits a TF to a STA. The TF can indicate an implied UL transmit power (TP) to be used by the STA for an uplink transmission to the AP. This value included in the trigger frame is referred to as an implied UL TP because the actual UL TP is known to the STA, but not theDocket No.: 24-3038PCTAP. The STA can compute the actual value of the UL TP based on a received power of the TF by the STA, an AP TX power parameter in the TF, and an UL target receive power that is also in the TF. This is discussed further, above, in relation to FIG. 8.

[0132] The STA can have multiple TP constraints (e.g., maximum and / or minimum TP levels). These constraints may include regulatory constraints (e.g., dependent on the country in which the STA is operating) and local transmit power constraints set by the AP (e.g., in a beacon and other management frames). The STA may further be constrained to a maximum TP depending on the MCS used by the STA for the uplink transmission (hereinafter referred to as STA maximum TP). A higher TP typically causes more non-linearities in the power amplifiers. Because a higher MCS is generally more sensitive to non-linearities, a higher MCS tends to have a lower STA maximum TP constraint. It is noted that the STA maximum TP may be the same for one or more MCSs. This may happen if a local maximum transmit power constraint or regulatory constraint is lower than the MCS dependent constraint.

[0133] If the implied UL TP is lower than the STA maximum TP of the STA, the STA uses the implied UL TP for the MCS as the uplink transmit power (UL TP) for the uplink transmission. The STA then indicates the difference between the STA maximum TP and the implied TP in an UL TP headroom report included in the uplink transmission. The AP may use this UL TP headroom report to increase the implied UL TP setting for higher reliability, higher throughput, or both. If the implied UL TP is greater than the STA maximum TP, the STA uses the STA maximum TP as the UL TP for the uplink transmission. The STA then indicates 0 in the UL TP headroom report.

[0134] FIG. 9 illustrates an example 900 of UL TP headroom reporting in the presence of an uplink transmit power constraint due to the STA. As illustrated, an AP 910 transmits a TF 912 to a STA 920. The TF 912 indicates an implied UL TP with a value B. The STA 920 has a STA maximum TP with a value A. In an example, the maximum TP with the value A may be a local maximum TP signaled by AP 910 to STA 920 prior to the sequence of frames shown in example 900. The signaling may be done by AP 910 by transmitting a frame (not shown in FIG. 9) including a transmit power envelope element (e.g. transmit power envelope element 500). In this example, B < A. Based on receiving TF 912, STA 920 transmits a data frame 922 with an UL TP of B. Because the actual UL TP used by the STA 920 for data frame 922 is B, which is less than the STA maximum TP of A of STA 920, STA 920 includes in data frame 922 an indication that the UL TP headroom is A-B.

[0135] On receiving data frame 922 with a positive UL TP headroom of A-B, AP 910 may decide to increase the implied uplink TP (e.g., to increase reliability, throughput, or both) and transmits another TF 914 to the STA 920. The TF 914 indicates an implied UL TP of A, matching the STA maximum TP of STA 920. The STA 920 receives the implied UL TP with the value A in the TF 914 and computes an UL TP headroom of 0 (e.g., because the implied UL TP of A matches the STA maximum TP of A). The STA 920 transmits a data frame 924 using the UL TP of A, and indicating a UL TP headroom of 0.Docket No.: 24-3038PCT

[0136] If the implied UL TP indicated by an AP to a STA in a TP is greater than a TP constraint (e.g. local max TP, regulatory max TP, STA max TP for the MCS), the STA reports 0 in the UL TP headroom. Generally, an AP may avoid instances in which the UL TP Headroom is zero because such instances may indicate that the implied UL TP is set incorrectly. For example, the AP may set the MCS to a lower value to increase the UL TP Headroom.

[0137] FIG. 10 illustrates an example 1000 of UL TP headroom reporting in the presence of an uplink transmit power constraint due to a local maximum TP (local max TP). As illustrated, an AP 1010 transmits a frame 101 1 to an STA 1020 indicating that the local max TP for the STA 1020 should be set to the value A. The STA 1020 receives frame 1011 and sets the local max TP to A. This is merely an example. Compared to other TP constraints, the local max TP for the STA 1020 is completely controlled by the AP 1010 (e.g., to attempt to increase spatial reuse and increase throughput). In contrast, TP constraints due to regulatory laws or physical limitations of the STA cannot be controlled by the AP. In an example, the local max TP indication in frame 101 1 may be provided in a transmit power envelope element (e.g. transmit power envelope element 500).

[0138] The AP 1010 then transmits a TF 1012 to the STA 1020. The TF 1012 indicates an implied UL TP of B, where B > A, and an MCS value of 5 for use by the STA 1020 to transmit a data frame 1022. As the implied UL TP in the TF 1012 (e.g., 8) exceeds the local max TP for the STA 1020 (e.g., A), the STA 1020 transmits the data frame 1022 to the AP 1010 using an UL TP of A and indicating a UL TP headroom of 0. In example 1000, the maximum transmit power dependent on the MCS value is assumed to be greater than A.

[0139] In this example, when the AP 1010 receives data frame 1022 with the UL TP headroom of O, the AP 1010 may determine that the implied UL TP is too low for the MCS value of 5. The AP 1010 may thus decide to reduce the MCS for STA 1020 to prevent a zero UL TP headroom from the STA 1020. As such, the AP 1010 transmits a TF 1014 indicating an MCS value of 3 for STA 1020. Because the cause of the zero UL TP headroom is the local max TP of STA 1020, however, and not the value of the MCS used by the STA for uplink transmission, the STA 1020 transmits a data frame 1024 with an unchanged UL TP of A and a UL TP headroom that remains 0 (e.g., because the local max TP remains lower than the implied uplink TP).

[0140] As discussed above, FIG. 10 illustrates the AP not being able to identify that the zero UL TP headroom is caused by a local max TP for an STA (e.g., as opposed to an implied UL TP indicated by the AP to the STA). One possible solution to this problem is to include in a trigger based uplink transmission an indication that a zero UL TP headroom is due to a local max TP. For example, the uplink transmission frame may include a bit indicating that the reason for the zero UL TP headroom is a local max TP setting.

[0141] As one example, a data frame used in trigger-based uplink transmission (e.g., the data frame 700 illustrated in FIG. 7) can include a UPH control subfield with a UL power headroom subfield, a minimum transmit power flag subfield, and two reserved bits. One of these two reserved bits (e.g., a seventh bit in theDocket No.: 24-3038PCTUPH control subfield, after a five bit UL power headroom subfield and a one bit minimum transmit power flag subfield) can be set to 1 to indicate that a zero UL TP headroom is due to a local max TP.

[0142] FIG. 11 illustrates an example 1100 for reporting zero UL TP headroom due to a local max TP. As illustrated, an AP 11 10 transmits a frame 11 11 to an STA 1 120 indicating that the local max TP for the STA 1120 should be set to the value A. In an example, the indication of local max TP of A in frame 1 111 may be provided using a transmit power envelope element (e.g. transmit power envelope element 500). The STA 1120 receives frame 1111 and sets the local max TP to A. The AP 1 110 then transmits a TF 1112 to the STA 1120. The TF 11 12 indicates an implied UL TP of 8, where B > A, and an MCS value of 5 for use by the STA 1120 to transmit a frame 1 122 (e.g., a data frame). As the implied UL TP in the TF 1112 (e.g., 8) exceeds the local max TP for the STA 1 120 (e.g., A), the STA 1120 transmits frame 1122 to the AP 11 10 using an UL TP of A and indicating a UL TP headroom of 0. In example 1100, the maximum transmit power dependent on the MCS value is assumed to be greater than A.

[0143] Further, the STA 1 120 includes in frame 1 122 an indication (e.g., one or more bits) that the UL TP headroom of 0 is due to the local max TP. The AP 1110 receives frame 1122 and determines that the UL TP headroom being zero is caused by a low value of the local max TP at the STA 1120. The AP 1 110, therefore, may determine to increase the local max TP for the STA 1120 from A to C, where C > A. For example, the AP 1110 transmits a frame 11 13 indicating a local max TP of C. In an example, the indication of local max TP of C in frame 1113 may be provided using a transmit power envelope element (e.g. transmit power envelope element 500).

[0144] The AP 1 110 does not change the MCS (e.g., the AP 1 110 leaves the MCS at 5), because frame 1 122 indicated that the zero UL TP headroom was due to the local max TP being too low. The AP 1110 transmits a TF 1 114 including an implied UL TP of 8 and an MCS of 5. The STA 1 120 receives the TF 1114 and transmits to the AP 1110 a data response 1124 using a UL TP of 8 and indicating an UL TP headroom of C-B.

[0145] As illustrated in FIG. 1 1 , in an example an STA can provide to an AP both an indication of zero UL TP headroom, and an indication that this zero UL TP headroom is caused by a local max TP for the STA. But this does not provide sufficient information for the AP to effectively adjust the local max TP setting.

[0146] For example, an AP may increase the local max TP for an STA, after receiving an indication of zero UL TP headroom, and an indication that this zero UL TP headroom is caused by a local max TP for the STA. But the increased local max TP may still be lower than the implied UL TP. This is because the AP knows only that the UL TP headroom is zero due to the local max but does not know how much more headroom is needed.

[0147] FIG. 12 illustrates an example 1200 that highlights a problem that may arise in reporting zero UL TP headroom due to a local max TP. As illustrated, an AP 1210 transmits a frame 121 1 to an STA 1220 indicating that the local max TP for the STA 1220 should be set to the value A. In an example, the indication of localDocket No.: 24-3038PCT max TP of A in frame 1211 may be provided using a transmit power envelope element (e.g. transmit power envelope element 500). The STA 1220 receives frame 1211 and sets the local max TP to A. The AP 1210 then transmits a TF 1212 to the STA 1220. The TF 1212 indicates an implied UL TP of B, where B > A. As the implied UL TP in the TF 1212 (e.g., B) exceeds the local max TP for the STA 1220 (e.g., A), the STA 1220 transmits a frame 1222 (e.g., a data frame) to the AP 1210 using an UL TP of A and indicating a UL TP headroom of 0.

[0148] Further, the STA 1220 includes in frame 1222 an indication (e.g., one or more bits) that the UL TP headroom of 0 is due to the local max TP. The AP 1210 receives frame 1222, and determines that the UL TP headroom being zero is caused by a low value of the local max TP at the STA 1220. The AP 1210, therefore, may determine to increase the local max TP for the STA 1220 from A to C, where C > A. For example, the AP 1210 transmits a frame 1213 indicating the new local max TP of C. In an example, the indication of local max TP of C in frame 1213 may be provided using a transmit power envelope element (e.g. transmit power envelope element 500). But while C > A in this example, C remains lesser than B. That is, the new local max TP for the STA 1220 is greater than the previous local max TP for the STA 1220, but the new local max TP for the STA 1220 is still lower than the implied UL TP for the STA 1220.

[0149] Subsequently, the AP 1210 transmits a TF 1214 to the STA 1220 indicating an implied UL TP of B. The STA 1220 receives the TF 1214 and transmits a frame 1224 using a UL TP of C (e.g., equal to the new local max TP). Because C < B (e.g., the local max TP remains lower than the implied UL TP), in frame 1224, the STA 1220 again indicates to the AP 1210 a UL TP headroom of 0, due to the local max TP. Thus, despite the additional indication to the AP that the UL TP headroom of O is due to the local max TP (e.g., as indicated in frame 1222), the AP is not able to effectively change the local max TP to allow for sufficient UL TP headroom.

[0150] Embodiments of the present disclosure, as further described below, address the above-described problem associated with existing technologies. In an aspect, an AP may transmit to an STA a first frame indicating a first transmit power level for the STA. The AP may further transmit to the STA a trigger frame indicating: a second transmit power level used by the AP to transmit the trigger frame, and a target receive power level, at the AP, of a second frame. The AP may receive, from the STA, the second frame in response to the trigger frame, wherein, based on a third transmit power level exceeding the first transmit power level, the second frame indicates: the third transmit power level exceeding the first transmit power level, wherein the third transmit power level is based on the second transmit power level and the target received power level, and a difference between the third transmit power level and the first transmit power level. As described further below, this provides to the AP an indication of the difference between power level settings for the STA (e.g., a difference between a local max TP for the STA and an implied UL TP for the STA), which allows the AP to effectively identify both whether to change a local max TP for the STA and how to change the local max TP for the STA.Docket No.: 24-3038PCT

[0151] In an embodiment, an STA can address the problem identified in relation to FIG. 12 by indicating a TP offset (e.g., a difference) between the local max TP and the implied UL TP. An AP receiving this difference may then determine the value of a local max TP adjustment such that the implied UL TP is not constrained unnecessarily by the Local Max TP.

[0152] FIG. 13 illustrates an example 1300 of UL TP headroom reporting according to an embodiment. As illustrated, an AP 1310 transmits a frame 1311 to an STA 1320 indicating that the local max TP for the STA 1320 should be set to the value A. Frame 1311 may be a beacon frame. In an example, the indication of local max TP of A in frame 1311 may be provided using a transmit power envelope element (e.g. transmit power envelope element 500). The STA 1320 receives frame 1311 and sets the local max TP to A. The AP 1310 then transmits a TF 1312 to the STA 1320. The TF 1312 indicates an implied UL TP of B, where B > A. The implied UL TP in the TF 1312 (e.g., B) exceeds the local max TP for the STA 1320 (e.g., A). Therefore, the STA 1320 transmits a frame 1322 (e.g., a data frame) to the AP 1310 using an UL TP of A and indicating a UL TP headroom of 0.

[0153] Further, the STA 1320 includes in frame 1322 an indication (e.g., one or more bits) that the UL TP headroom of 0 is due to the local max TP. The STA 1320 also includes in frame 1322 an indication of the value of a TP offset. In an example, the TP offset is a difference between the implied UL TP and the local max TP, for the STA (e.g., B-A).

[0154] The AP 1310 receives frame 1322 and determines that the UL TP headroom being zero is caused by a low value of the local max TP at the STA 1320. The AP 1310 further identifies the TP offset (e.g., B-A) based on the indication in frame 1322. The AP 1310 then determines a value to adjust the local max TP based on the TP offset. For example, the AP 1310 may set the new local max TP to B + 5, where 5 is the TP offset (e.g., B-A). In an embodiment, 5 may further include an additional small value greater than 0 (e.g., to provide an additional cushion to avoid zero UL TP headroom). This is merely an example, and 5 may include just the TP offset or any suitable additional small value.

[0155] Subsequently, AP 1310 transmits a frame 1313 indicating the new local max TP of B + 6. Frame 1313 may be a beacon frame. In an example, the indication of local max TP of B + 5 in frame 1313 may be provided using a transmit power envelope element (e.g. transmit power envelope element 500). The AP 1310 then transmits a TF 1314 indicating an implied UL TP of B (e.g., unchanged from the prior TF 1312). The STA 1320 receives the TF 1314, and transmits a frame 1324 using a UL TP of 8. The STA 1320 further indicates an UL TP headroom of 5, and does not indicate zero UL TP headroom (e.g., sets the zero UL TP headroom bit(s) to low or 0). As the implied UL TP is no longer constrained by the local max TP, STA 1320 is able to transmit using the implied UL TP with non-zero UL TP headroom. Thus, at least based on the foregoing, embodiments depicted with FIG. 13 may avoid the problem described above with FIG. 12 and improve local max TP allocation by the AP. For example, the AP can appropriately increase a local max TPDocket No.: 24-3038PCT setting for a STA, so that an implied UL TP setting is not constrained by the local max TP at the STA, improving reliability and throughput.

[0156] FIG. 14 illustrates enhanced UPH control for UL TP headroom reporting according to an embodiment. In an embodiment, an STA (e.g., the STA 1320 illustrated in FIG. 13) can use an enhanced UPH control subfield 1400 to report a TP offset. As discussed above in relation to FIG. 7, a data frame 700 can include a UPH control subfield with a UL power headroom subfield, a minimum transmit power flag subfield, and two reserved bits. A data frame (e.g., frame 1322 illustrated in FIG. 13) can instead, or in addition, include an enhanced UPH control subfield 1400.

[0157] In an embodiment, the enhanced UPH control subfield 1400 includes a UL power headroom negative subfield, in addition to the existing UL power headroom subfield and minimum transmit power flag subfield. The UL power headroom negative subfield (e.g., a one bit flag using one of the two reserved bits in the UPH control subfield) indicates whether the value of UL power headroom subfield uses the baseline definition or a new definition.

[0158] In an embodiment, if the UL power headroom negative subfield is set to 0, the UL power headroom is defined as the available UL power headroom (e.g., as described above in relation to FIG. 7). In this example, the UL power headroom for an STA is equal to a local max TP - implied UL TP, when the minimum of all applicable TP constraints for the STA is the local max TP. If the UL power headroom negative subfield is set to 1 , the UL power headroom subfield is defined to be equal to implied UL TP - local max TP, when the minimum of all applicable TP constraint is the Local Max TP.

[0159] Effectively, the STA sets the UL power headroom negative subfield to 1 when the local max TP - implied UL TP is negative (e.g., the implied UL TP is larger than the local max TP). The UL power headroom then includes the TP offset, as discussed above in relation to FIG. 13, which the STA can transmit to the AP and the AP can use to appropriately modify the local max TP for the STA (as needed). In this example, the seventh bit of the enhanced UPH control subfield 1400 is set to one whenever the UL power headroom is zero or negative, matching the example behavior discussed above in relation to FIG. 1 1 (e.g., setting a zero headroom due to local max TP flag to 1).

[0160] FIG. 15 illustrates a further example of enhanced UPH control for UL TP headroom reporting according to an embodiment. In an embodiment, an STA (e.g., the STA 1320 illustrated in FIG. 13) can use an enhanced UPH control subfield 1500 to report a TP offset. The enhanced UPH control subfield 1500 illustrates an alternative, or additional, embodiment for the enhanced UPH control subfield 1400 illustrated in FIG. 14.

[0161] As discussed above in relation to FIG. 7, a data frame 700 can include a UPH control subfield with a UL power headroom subfield, a minimum transmit power flag subfield, and two reserved bits. A data frame (e.g., frame 1322 illustrated in FIG. 13) can instead, or in addition, include an enhanced UPH control subfield 1500. In an embodiment, the enhanced UPH control subfield 1500 includes a UL power headroom / impliedDocket No.: 24-3038PCTTP flag subfield. The UL power headroom / implied TP flag subfield (e.g., a one bit flag using one of the two reserved bits in the UPH control subfield) indicates whether the value of UL power headroom subfield includes the UL power headroom of the STA or the implied UL TP of the STA.

[0162] In an embodiment, if the UL power headroom / implied TP flag subfield is set to 0, the UL power headroom is defined as the available UL power headroom (e.g., as described above in relation to FIG. 7). In this example, the UL power headroom for an STA is equal to a local max TP - implied UL TP, when the minimum of all applicable TP constraints for the STA is the local max TP. If the UL power headroom / implied TP flag subfield is set to 1 the UL power headroom subfield is set to be equal to the implied UL TP, when the minimum of all applicable TP constraints is the local max TP.

[0163] Effectively, the STA sets the UL power headroom / implied TP flag subfield to 1 when the local max TP - implied UL TP is negative (e.g., the implied UL TP is larger than the local max TP). But instead of including in the UL power headroom a TP offset as negative value, as discussed above in relation to FIG. 14, the STA includes the implied UL TP in the UL power headroom subfield. The AP knows the local max TP at the STA, but does not know the actual implied UL TP used by the STA, and so the AP can receive the actual implied UL TP in the UL power headroom subfield and use it to appropriately modify the local max TP for the STA (as needed). As above for the enhanced UPH control subfield 1400 illustrated in FIG. 14, the seventh bit of the enhanced UPH control subfield 1500 is set to one whenever the UL power headroom is zero or negative, matching the example behavior discussed above in relation to FIG. 1 1 (e.g., setting a zero headroom due to local max TP flag to 1).

[0164] FIG. 16 illustrates another example of enhanced UPH control for UL TP headroom reporting according to an embodiment. In an embodiment, an STA (e.g., the STA 1320 illustrated in FIG. 13) can use an enhanced UPH control subfield 1600 to report a TP offset. The enhanced UPH control subfield 1600 illustrates an alternative, or additional, embodiment for the enhanced UPH control subfields 1400 illustrated in FIG. 14 and 1500 illustrated in FIG. 15.

[0165] As discussed above in relation to FIG. 7, a data frame 700 can include a UPH control subfield with a UL power headroom subfield, a minimum transmit power flag subfield, and two reserved bits. A data frame (e.g., frame 1322 illustrated in FIG. 13) can instead, or in addition, include an enhanced UPH control subfield 1600. In an embodiment, the enhanced UPH control subfield 1600 includes a zero headroom due to local max TP subfield and a UL power headroom / implied TP flag subfield. The zero headroom due to local max TP subfield (e.g., a one bit flag using one of the two reserved bits in the UPH control subfield) can indicate that the STA has zero headroom due to a local max, as discussed above in relation to FIG. 11.

[0166] Further, in an embodiment, the UL power headroom / implied TP flag subfield (e.g., a one bit flag using the other of the two reserved bits in the UPH control subfield). As in the enhanced UPH control subfield 1500 illustrated in FIG. 15, the UL power headroom / implied TP flag subfield indicates whether the value of UL power headroom subfield includes the UL power headroom of the STA or the implied UL TP of the STA.Docket No.: 24-3038PCT

[0167] In an embodiment, if the UL power headroom / implied TP flag subfield is set to 0, the UL power headroom is defined as the available UL power headroom (e.g., as described above in relation to FIG. 7). In this example, the UL power headroom for an STA is equal to a local max TP - implied UL TP, when the minimum of all applicable TP constraints for the STA is the local max TP. If the UL power headroom / implied TP flag subfield is set to 1 the UL power headroom subfield is set to be equal to the implied UL TP, when the minimum of all applicable TP constraints is the local max TP.

[0168] Effectively, the STA sets the UL power headroom / implied TP flag subfield to 1 when the local max TP - implied UL TP is negative (e.g., the implied UL TP is larger than the local max TP). But instead of including in the UL power headroom a TP offset as negative value, as discussed above in relation to FIG. 14, the STA includes the implied UL TP in the UL power headroom subfield. The AP knows the local max TP at the STA, but does not know the actual implied UL TP used by the STA, and so the AP can receive the actual implied UL TP in the UL power headroom subfield and use it to appropriately modify the local max TP for the STA (as needed). The enhanced UPH control subfield 1600 further includes the zero headroom due to local max TP subfield, matching the example behavior discussed above in relation to FIG. 11 (e.g., setting a zero headroom due to local max TP flag to 1 ).

[0169] As would be understood by a person of skill in the art based on the teachings herein, the embodiments as described by the above examples may be readily extended to implementations including more than one STA.

[0170] As would be understood by a person of skill in the art based on the teachings herein, the embodiments as described by the above examples may be readily extended to implementations including more than one AP.

[0171] As would be understood by a person of skill in the art based on the teachings herein, the embodiments as described by the above examples may be readily extended to scenarios in which any of the APs or any of the STAs may comprise a MLD, comprising at least one affiliated AP or affiliated STA.

[0172] FIG. 17 illustrates an example process 1700 according to an embodiment of the present disclosure. Example process 1700 may be performed by a first STA, such as AP 1310 illustrated in FIG. 13. As shown in FIG. 17, process 1700 may include steps 1702 and 1704.

[0173] Step 1702 includes transmitting, by a first station (STA) to a second STA, a trigger frame. In an embodiment the second STA comprises a non-AP STA, such as STA 1320 illustrated in FIG. 13, for example.

[0174] Step 1704 includes receiving, by the first STA from the second STA, a second frame, with the second frame indicating a difference between a first transmit power level and a second transmit power level based on the first transmit power level exceeding the second transmit power level, and with the first transmit power level being based on the trigger frame.

[0175] In an embodiment the first STA further transmits to the second STA a third frame including the second transmit power level.Docket No.: 24-3038PCT

[0176] In an embodiment, the second transmit power level is provided in a first transmit power envelope element of the third frame.

[0177] In an embodiment, the third frame includes a beacon frame, a probe response frame, or an association response frame.

[0178] In an embodiment the first STA further transmits to the second STA a fourth frame including a second transmit power envelope element.

[0179] In an embodiment the second transmit power envelope element includes a third transmit power level for the second STA, wherein the third transmit power level is based on the difference between the first transmit power level and second transmit power level. In an example, the third transmit power level may include the first transmit power level.

[0180] In an embodiment the second frame further includes an indication that the first transmit power level exceeds the second transmit power level.

[0181] In an embodiment the trigger frame includes an uplink target receive power level, at the first STA, of the second frame. In an embodiment the trigger frame further includes a fourth transmit power level used by the first STA to transmit the trigger frame.

[0182] In an embodiment the first transmit power level is based on the fourth transmit power level and the uplink target receive power level.

[0183] In an embodiment the difference between the first transmit power level and the second transmit power level is indicated in a high throughput (HT) control field of the second frame.

[0184] In an embodiment the difference between the first transmit power level and the second transmit power level is indicated in an uplink power headroom (UPH) field of the HT control field.

[0185] In an embodiment the difference between the first transmit power level and the second transmit power level is indicated in one or more bits of the UPH field.

[0186] In an embodiment the UPH field includes a bit that indicates whether the difference between the first transmit power level and the second transmit power level is indicated in the one or more bits of the UPH field.

[0187] In an embodiment the difference between the first transmit power level and the second transmit power level includes an absolute value of the difference between the first transmit power level and the second transmit power level and a sign value of the difference.

[0188] In an embodiment the difference between the first transmit power level and the second transmit power level includes the second transmit power level.

[0189] In an embodiment the first transmit power level includes a local maximum transmit power level.

[0190] In an embodiment the second STA includes a non-AP STA.

[0191] In an embodiment the first STA includes an AP.

[0192] In an embodiment, based on the first transmit power level exceeding the second transmit power level, the second frame is transmitted using the second transmit power level.Docket No.: 24-3038PCT

[0193] FIG. 18 illustrates an example process 1800 according to an embodiment of the present disclosure. Example process 1800 may be performed by a first STA, such as STA 1320 illustrated in FIG. 13. As shown in FIG. 18, process 1800 may include steps 1802, 1804, and 1806.

[0194] Step 1802 includes receiving, by a first station (STA) from a second STA, a trigger frame. In an embodiment the second STA comprises an AP, such as AP 1310 illustrated in FIG. 13, for example.

[0195] Step 1804 includes determining, by the first STA, a first transmit power level based on the trigger frame.

[0196] Step 1806 includes transmitting, by the first STA to the second STA, a second frame, with the second frame indicating a difference between a first transmit power level and a second transmit power level based on the first transmit power level exceeding a second transmit power level.

[0197] In an embodiment the first STA further receives, from the second STA, a third frame including the second transmit power level.

[0198] In an embodiment, the second transmit power level is provided in a first transmit power envelope element of the third frame.

[0199] In an embodiment, the third frame includes a beacon frame, a probe response frame, or an association response frame.

[0200] In an embodiment the first STA further receives, from the second STA, a fourth frame including a second transmit power envelope element.

[0201] In an embodiment the second transmit power envelope element includes a third transmit power level for the second STA, wherein the third transmit power level is based on the difference between the first transmit power level and second transmit power level. In an example, the third transmit power level may include the first transmit power level.

[0202] In an embodiment the second frame further includes an indication that the first transmit power level exceeds the second transmit power level.

[0203] In an embodiment the trigger frame includes an uplink target receive power level, at the second STA, of the second frame. In an embodiment the trigger frame further includes a fourth transmit power level used by the second STA to transmit the trigger frame.

[0204] In an embodiment determining the first transmit power level based on the trigger frame includes determining the first transmit power level based on the fourth transmit power level and the uplink target receive power level.

[0205] In an embodiment the difference between the first transmit power level and the second transmit power level is indicated in a high throughput (HT) control field of the second frame.

[0206] In an embodiment the difference between the first transmit power level and the second transmit power level is indicated in an uplink power headroom (UPH) field of the HT control field.Docket No.: 24-3038PCT

[0207] In an embodiment the difference between the first transmit power level and the second transmit power level is indicated in one or more bits of the UPH field.

[0208] In an embodiment the UPH field includes a bit that indicates whether the difference between the first transmit power level and the second transmit power level is indicated in the one or more bits of the UPH field.

[0209] In an embodiment the difference between the first transmit power level and the second transmit power level includes an absolute value of the difference between the first transmit power level and the second transmit power level and a sign value of the difference.

[0210] In an embodiment the difference between the first transmit power level and the second transmit power level includes the second transmit power level.

[0211] In an embodiment the first transmit power level includes a local maximum transmit power level.

[0212] In an embodiment the second STA includes an AP.

[0213] In an embodiment the first STA comprises a non-AP STA.

[0214] In an embodiment, based on the first transmit power level exceeding the second transmit power level, the second frame is transmitted using the second transmit power level.

Claims

Docket No.: 24-3038PCTCLAIMSWhat is claimed is:

1. A method comprising: transmitting, by an access point (AP) to a station (STA), a first frame indicating a first transmit power level for the STA; transmitting, by the AP to the STA, a trigger frame indicating: a second transmit power level used by the AP to transmit the trigger frame; and a target receive power level, at the AP, of a second frame; and receiving, by the AP from the STA, the second frame in response to the trigger frame, wherein, based on a third transmit power level exceeding the first transmit power level, the second frame indicates: the third transmit power level exceeding the first transmit power level, wherein the third transmit power level is based on the second transmit power level and the target receive power level; and a difference between the third transmit power level and the first transmit power level.

2. A method comprising: transmitting, by a first station (STA) to a second STA, a trigger frame; and receiving, by the first STA from the second STA, a second frame, wherein, based on a first transmit power level exceeding a second transmit power level, the second frame indicates a difference between the first transmit power level and the second transmit power level, wherein the first transmit power level is based on the trigger frame.

3. The method of claim 2, further comprising transmitting, by the first STA to the second STA, a third frame comprising the second transmit power level.

4. The method of claim 3, wherein the second transmit power level is provided in a first transmit power envelope element of the third frame.

5. The method of any of claims 3-4, wherein the third frame comprises a beacon frame, a probe response frame or an association response frame.

6. The method of any of claims 2-5, further comprising transmitting, by the first STA to the second STA, a fourth frame comprising a second transmit power envelope element.

7. The method of claim 6, wherein the second transmit power envelope element comprises a third transmit power level for the second STA, wherein the third transmit power level comprises the first transmit power level.

8. The method of any of claims 2-7, wherein the second frame further comprises an indication that the first transmit power level exceeds the second transmit power level.

9. The method of any of claims 2-8, wherein the trigger frame comprises:Docket No.: 24-3038PCT an uplink target receive power level, at the first STA, of the second frame; and a fourth transmit power level used by the first STA to transmit the trigger frame.

10. The method of claim 9, wherein the first transmit power level is based on the fourth transmit power level and the uplink target receive power level.11 . The method of any of claims 2-10, wherein the difference between the first transmit power level and the second transmit power level is indicated in a high throughput (HT) control field of the second frame.

12. The method of claim 11 , wherein the difference between the first transmit power level and the second transmit power level is indicated in an uplink power headroom (UPH) field of the HT control field.

13. The method of claim 12, wherein the difference between the first transmit power level and the second transmit power level is indicated in bits B0-B4 of the UPH field.

14. The method of claim 13, wherein whether the difference between the first transmit power level and the second transmit power level is indicated in bits B0-B4 of the UPH field is indicated in a bit B6 or a bit B7 if the UPH field.

15. The method of any of claims 2-14, wherein the difference between the first transmit power level and the second transmit power level comprises an absolute value of the difference between the first transmit power level and the second transmit power level and a sign value of the difference.

16. The method of any of claims 2-14, wherein the difference between the first transmit power level and the second transmit power level comprises the second transmit power level.

17. The method of any of claims 2-16, wherein the first transmit power level comprises a local maximum transmit power level.

18. The method of any of claims 2-17 wherein the second STA comprises an access point (AP).

19. The method of any of claims 2-18, wherein the first STA comprises a non-AP STA.

20. The method of any of claims 2-19, wherein based on the first transmit power level exceeding the second transmit power level, the second frame is transmitted using the second transmit power level.21 . A method comprising: receiving, by a station (STA) from an access point (AP), a first frame indicating a first transmit power level for the STA; receiving, by the STA from the AP, a trigger frame indicating: a second transmit power level used by the AP to transmit the trigger frame; and a target receive power level, at the AP, of a second frame, wherein the second frame is transmitted by the STA to the AP in response to the trigger frame; determining, by the STA, a third transmit power level based on the second transmit power level and the target receive power level; andDocket No.: 24-3038PCT transmitting, by the STA to the AP, the second frame, wherein, based on the third transmit power level exceeding the first transmit power level, the second frame indicates: the third transmit power level exceeding the first transmit power level; and a difference between the third transmit power level and the first transmit power level.

22. A method comprising: receiving, by a first station (STA) from a second STA, a trigger frame; determining, by the first STA, a first transmit power level based on the trigger frame; and transmitting, by the first STA to the second STA, a second frame, wherein, based on the first transmit power level exceeding a second transmit power level, the second frame indicates a difference between the first transmit power level and the second transmit power level.

23. The method of claim 22, further comprising receiving, by the first STA from the second STA, a third frame comprising the second transmit power level.

24. The method of claim 23, wherein the second transmit power level is provided in a first transmit power envelope element of the third frame.

25. The method of any of claims 23-24, wherein the third frame comprises a beacon frame, a probe response frame, or an association response frame.

26. The method of any of claims 22-25, further comprising receiving, by the first STA from the second STA, a fourth frame comprising a second transmit power envelope element.

27. The method of claim 26, wherein the second transmit power envelope element comprises a third transmit power level for the first STA, and wherein the third transmit power level comprises the second transmit power level.

28. The method of any of claims 22-27, wherein the second frame further comprises an indication that the first transmit power level exceeds the second transmit power level.

29. The method of any of claims 22-28, wherein the trigger frame comprises: an uplink target receive power level, at the second STA, of the second frame; and a fourth transmit power level used by the second STA to transmit the trigger frame.

30. The method of claim 29, wherein determining the first transmit power level based on the trigger frame comprises determining the first transmit power level based on the fourth transmit power level and the uplink target receive power level.31 . The method of any of claims 22-30, wherein the difference between the first transmit power level and the second transmit power level is indicated in a high throughput (HT) control field of the second frame.

32. The method of claim 31 , wherein the difference between the first transmit power level and the second transmit power level is indicated in an uplink power headroom (UPH) field of the HT control field.Docket No.: 24-3038PCT33. The method of claim 32, wherein the difference between the first transmit power level and the second transmit power level is indicated in one or more bits of the UPH field.

34. The method of claim 33, wherein the UPH field comprises a bit that indicates whether the difference between the first transmit power level and the second transmit power level is indicated in the one or more bits of the UPH field.

35. The method of any of claims 22-34, wherein the difference between the first transmit power level and the second transmit power level comprises an absolute value of the difference between the first transmit power level and the second transmit power level and a sign value of the difference.

36. The method of any of claims 22-34, wherein the difference between the first transmit power level and the second transmit power level comprises the second transmit power level.

37. The method of any of claims 22-36, wherein the first transmit power level comprises a local maximum transmit power level.

38. The method of any of claims 22-37, wherein the second STA comprises an access point (AP).

39. The method of any of claims 22-38, wherein the first STA comprises a non-AP STA.

40. The method of any of claims 22-39, wherein based on the first transmit power level exceeding the second transmit power level, the second frame is transmitted using the second transmit power level.

41. A device comprising: one or more processors; and memory storing instructions that, when executed by the one or more processors, cause the device to perform a method according to any of claims 1-40.

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

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