Access point (AP) power saving operations during a triggered transmission opportunity sharing procedure

Abstract

An access point (AP) transmits a first frame allocating to a first station (STA) a portion of a transmission opportunity (TXOP) obtained by the AP. After transmitting the first frame and before or within the portion of the TXOP, the AP transitions from a first power state / mode to a second power state / mode of a power save mode. After transitioning from the first power state / mode to the second power state / mode, the AP receives from the first STA a second frame causing the AP to transition from the second power state / mode to the first power state / mode; and transitions from the second power state / mode to the first power state / mode, in response to the second frame.

Description

TITLEAccess Point (AP) Power Saving Operations During a Triggered Transmission Opportunity Sharing Procedure CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 562,730, filed March 8, 2024, and U.S. Provisional Application No. 63 / 563,998, filed March 12, 2024, all of which are hereby incorporated by reference in their entireties.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 multi-user request to send (MU-RTS) transmission opportunity sharing (TXS) trigger (MRTT) frame which may be used in a TXS procedure.

[0006] FIG. 4 illustrates an example of a TXS procedure (Mode =1).

[0007] FIG. 5 illustrates an example of a TXS procedure (Mode =2).

[0008] FIG. 6 illustrates a non-High Throughput (non-HT) Physical Layer Protocol Data Unit(PPDU), a High Throughput (HT) mixed PPDU, and a Very High Throughput (VHT) PPDU.

[0009] FIG. 7 illustrates a High Efficiency (HE) Single User (SU) PPDU, an HE Multi-User (MU) PPDU, and an HE Extended Range (ER) SU PPDU.

[0010] FIG. 8 illustrates an Extremely High Throughput (EHT) Multi-user (MU) PPDU.

[0011] FIG. 9 illustrates an example of a power save mode.

[0012] FIG. 10 illustrates an example of an AP implementation of the power save mode illustrated in FIG. 9.

[0013] FIG. 11 is an example that illustrates an inefficient STA operation that may occur during the TXS procedure illustrated in FIGs. 4 and 5.

[0014] FIG. 12 illustrates an example of an AP power saving operation that may be used in a TXS procedure according to an embodiment.

[0015] FIG. 13 illustrates an example of an AP power saving operation that may be used in a TXS procedure according to an embodiment.

[0016] FIG. 14 illustrates an example of an AP power saving operation that may be used in a TXS procedure according to an embodiment.

[0017] FIG. 15 illustrates an example of an AP power saving operation that may be used in a TXS procedure according to an embodiment.

[0018] FIG. 16 illustrates an example of an AP power saving operation that may be used in a TXS procedure according to an embodiment.

[0019] FIG. 17 illustrates an example process according to an embodiment.

[0020] FIG. 18 illustrates an example process according to an embodiment.

[0021] FIG. 19 illustrates an example process according to an embodiment.

[0022] FIG. 20 illustrates an example process according to an embodiment.DETAILED DESCRIPTION

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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 suitable 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 “employi ng / 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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 behavioral ly equivalent. For example, modules may be implemented as a software routine written in a computer language configured to be executed by ahardware 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.

[0031] FIG. 1 illustrates example 100 wireless communication networks in which embodiments of the present disclosure may be implemented. 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) 110 and 120 and a distribution system (DS) 130.

[0032] 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 110-2 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.

[0033] 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).

[0034] 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.

[0035] 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).

[0036] 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 does 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.

[0037] 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, wirelessdevice, wireless transmit / receive unit (WTRU), user equipment (UE), mobile station (MS), mobile subscriber unit, or user. For example, the term “user” maybe 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.

[0038] 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 service data unit (PSDU). For example, the PSDU may include a PHY preamble and header and / or one or more MAC protocol data units (MPDUs). The information provided in the PHY preamble may be used by a receiving device to decode the subsequent data in the PSDU. In instances in which PPDUs are transmitted overa 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 802.11 protocol to be used to transmit the payload.

[0039] A frequency band may include one or more sub-bands or frequency channels. For example, PPDUs conforming to the IEEE 802.11n, 802.11ac, 802.11 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 320 MHz by bonding together multiple 20 MHz channels.

[0040] FIG. 2 is a block diagram 200 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.

[0041] 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 more 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.

[0042] 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-transi tory 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.

[0043] 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.

[0044] FIG. 3 illustrates an example MRTT frame 300 which may be used in a TXS procedure. As shown in FIG. 3, example MRTT frame 300 may comprise 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 / or frame check sequence (FCS) field.

[0045] In an example, the common info field may be a high-efficiency (HE) variant common info field or an extremely high throughput (EHT) variant common info field. An EHT variant common info field may comprise, as shown in FIG. 3, one or more of the following subfields: trigger type, UL length, more TF, CS required, UL BW, Gl and HE / EHT-LTF Type / Triggered TXOP sharing mode, number of HE / EHT-LTF symbols, LDPC extra symbol segment, AP Tx Power, Pre- FEC padding factor, PE disambiguity, UL spatial reuse, HE / EHT P160, special user info field flag, EHT reserved, reserved, or trigger dependent common info.

[0046] The trigger type subfield indicates that frame 300 is an MRTT frame.

[0047] The Gl and HE / EHT-LTF Type / Triggered TXOP sharing mode subfield may include a triggered TXOP sharing mode subfield. In an example, the triggered TXOP sharing mode subfield may be set to a non-zero value (e.g., 1 or 2). In an example, the triggered TXOP sharing mode subfield may be set to one (1). As such, the triggered TXOP sharing mode subfield may indicate that a STA indicated by an AID12 subfield of a user info field (of the user info list field) may transmit one or more non-TB PPDUs to the AP during a time indicated in the allocation duration subfield of the user info field. In another example, the triggered TXOP sharing mode subfield may be set to 2. As such, the triggered TXOP sharing mode subfield may indicate that a STA indicated by an AID12 subfield of a user info field (of the user info list field) may transmit one or more non-TB PPDUs to the AP or to a peer STA during the time indicated by the allocation duration subfield of the user info field. In an example, the peer STA may be a STA with a connection for P2P communication or direct communication with the STA.

[0048] The user info list field may include one or more user info fields. In an example, an EHT variant user info field may comprise, as shown in FIG. 3, one or more of the following subfields: AID12, RU allocation, allocation duration, reserved, or PS160.

[0049] The AID12 subfield may indicate an association identifier (AID) of a STA that may use a time indicated by the allocation duration subfield.

[0050] The RU allocation subfield may indicate the location and size of the RU allocated for a STA indicated by the AID12 subfield.

[0051] The allocation duration subfield may indicate a time allocated by an AP transmitting MRTT frame 300. The allocated time may be a portion a TXOP obtained by the AP. In an example embodiment, the allocation duration subfield may indicate a first time period.

[0052] FIG. 4 illustrates an example 400 of a TXS procedure (Mode =1). As shown in FIG. 4, the TXS procedure may begin by an AP 410 transmitting an MRTT frame 420 to a STA 411 . MRTT frame 420 may allocate a portion of a TXOP obtained by AP 410 to STA 411 and may indicate a TXS mode equal to 1 . STA 411 receiving MRTT frame 420 may use the allocated time to transmit one or more non-TB PPDUs to AP 410. The one or more non-TB PPDUs may comprise a data frame, a control frame, a management frame, or an action frame.

[0053] In an example, MRTT frame 420 may comprise a triggered TXOP sharing mode subfield that indicates the TXS mode and / or subfield that indicates a first time period corresponding to the allocated time. In an example, the first time period may be set to a value of X microseconds (us).

[0054] STA411 may respond to MRTT frame 420 by transmitting a CTS frame 421 to AP 410. Subsequently, STA 411 may transmit non-TB PPDUs 422, 424 comprising one or more data frame to AP 410 during the first time period indicated in MRTT frame 420. In an example, AP 410 may transmit one or more BA frames 423, 425 in response to the one or more data frames contained in non-TB PPDUs 422, 424 received from STA 411 .

[0055] FIG. 5 illustrates an example 500 of a TXS procedure (Mode =2). As shown in FIG. 5, the TXS procedure may begin by an AP 510 transmitting an MRTT frame 520 to a STA 511 . MRTT frame 520 may allocate a portion of a TXOP obtained by AP 510 to STA 511 and may indicate a TXS mode equal to 2. STA 511 receiving MRTT frame 520 may use the allocated time to transmit one or more non-TB PPDUs to STA 512. The one or more non-TB PPDUs may comprise a data frame, a control frame, a management frame, or an action frame.

[0056] In an example, MRTT frame 520 may comprise a triggered TXOP sharing mode subfield that indicates the TXS mode and / or subfield that indicates a first time period corresponding to the allocated time. In an example, the first time period may be set to a value of X microseconds (us).

[0057] STA511 may respond to MRTT frame 520 by transmitting a CTS frame 521 to AP 510 Subsequently, STA 511 may transmit non-TB PPDUs 522, 524 comprising one or more data frame to STA 512 during the first time period indicated in MRTT frame 520. In an example, STA 512 may transmit one or more BA frames 523, 525 in response to the one or more data frames contained in non-TB PPDUs 522, 524 received from STA 511 .

[0058] FIG. 6 illustrates a non- High Throughput (non-HT) PPDU 610, a High Throughput (HT) mixed mode PPDU 620, and a Very High Throughput (VHT) PPDU 630.

[0059] Non-HT PPDU 610 may be used by STAs conforming to the IEEE 802.11a standard amendment. As shown in FIG. 6, non-HT PPDU 610 includes a non-HT Short Training field (L-STF), a non-HT Long Training field (L-LTF), a non- HT Signal field (L-SIG), and a Data field. The L-STF, L-LTF, and L-SIG form a 20 pis preamble of non-HT PPDU 610.

[0060] The L-STF may be used by a receiver of non-HT PPDU 610 to synchronize with the carrier frequency and frame timing of a transmitter of non-HT PPDU 610 and to adjust the receiver signal gain. The L-LTF may be used by the receiver of non-HT PPDU 610 to estimate channel coefficients in order to equalize the channel response (e.g., amplitude and phase distortion) in both the L-SIG and the Data fields of non-HT PPDU 610.

[0061] The L-SIG contains parameters needed to demodulate the Data field, which contains a payload of non-HT PPDU 610. The L-SIG may be equalized using the channel coefficients estimated using the L-LTF and demodulated to obtainthe demodulation parameters of the Data field. The Data Field includes one or more symbols each having a duration of 4 pis, where 3.2 pis carry symbol information and 0.8 pis carry a Guard Interval (Gl).

[0062] For non-HT PPDUs, the only supported bandwidth is 20 MHz, which is divided into 64 subcarriers. As such, non- HT PPDU 610 may be encoded using a subcarrier spacing of 20MHz / 64 or 312.5kHz.

[0063] HT mixed mode PPDU 620 may be used by STAs conforming to the IEEE 802.11n standard amendment. HT mixed mode PPDU 620 can support MIMO to up to 4 spatial streams, which enhances spectral efficiency four folds. HT mixed mode PPDU 620 has a minimum preamble duration of 35.6 ps, which may increase depending on the number of spatial streams carried by the PPDU.

[0064] As shown in FIG. 6, HT mixed mode PPDU 620 includes an L-STF, an L-LTF, an L-SIG, an HT Signal field (HT- SIG) field, an HT Short Training field (HT-STF) field, one or more HT Long Training field (HT-LTF), and a data field. The HT-LTF and data fields include of one or more symbols each having a duration of 3.6 ps or 4 ps. In both cases, 3.2 ps carry symbol information while the remaining 0.4 ps or 0.8 ps carry a Gl. The 0.4 ps long Gl is called short Gl while the 0.8 ps long Gl is called regular or normal Gl.

[0065] For HT mixed mode PPDUs, two bandwidths, 20 MHz and 140 MHz, may be supported. When the PPDU bandwidth is 20MHz, the band is divided into 64 subcarriers. When the PPDU bandwidth is 140 MHz, the band is divided into 128 subcarriers. In both cases, subcarrier spacing of 312.5 kHz is maintained.

[0066] VHT PPDU 630 may be used by STAs conforming to the IEEE 802.11 ac standard amendment. VHT PPDU 630 can support MIMO transmission to up to 8 spatial streams, which enhances spectral efficiency eight folds. VHT PPDU 630 has a minimum preamble duration of 39.6 ps, which may increase depending on the number of spatial streams carried by VHT PPDU 630.

[0067] As shown in FIG. 6, VHT PPDU 630 includes an L-STF, an L-LTF, an L-SIG, a VHT Signal A field (VHT-SIG- A), a VHT Short Training field (VHT-STF), one or more VHT Long Training field (VHT-LTF), a VHT Signal B field (VHT- SIG-B), and a Data field. The VHT-LTF and Data fields of VHT PPDU 630 include one or more symbols each having a duration of 3.6 ps or 4 ps. In both cases, 3.2 ps carry symbol information while the remaining 0.4 ps or 0.8 ps carry of the Gl. The 0.4 ps long Gl is called the Short Gl while the 0.8ps long is called regular or normal Gl.

[0068] For VHT PPDUs, four bandwidths, 20 MHz, 40 MHz, 80 MHz, and 160 MHz, may be supported. When the PPDU bandwidth is 20MHz, the band is divided into 64 subcarriers. When the PPDU bandwidth is 40 MHz, the band is divided into 128 subcarriers. When the PPDU bandwidth is 80MHz, the band is divided into 256 subcarriers. When the PPDU bandwidth is 160 MHz, the band is divided into two 256-subcarrier 80 MHz bands. In all cases, a subcarrier spacing of 312.5 kHz is maintained.

[0069] FIG. 7 illustrates a High Efficiency (HE) Single User (SU) PPDU 710, an HE Multi-User (MU) PPDU 720, and an HE Extended Range (ER) SU PPDU 730. HE SU PPDU 710, HE MU PPDU 720, and HE ER SU PPDU 730 may be used by STAs conforming to the IEEE 802.11 ax standard amendment.

[0070] HE SU PPDU 710 supports higher spectral efficiency compared to VHT PPDU 330 due to increased subcarrier spacing and higher order modulation support. HE SU PPDU 710 has a minimum preamble duration of 44 pis.

[0071] As shown in FIG. 7, HE SU PPDU 710 includes an L-STF, an L-LTF, an L-SIG, a Repeated L-SIG (RL-SIG), an HE Signal A field (HE-SIG-A), an HE Short Training field (HE-STF) field, one or more HE Long Training field (HE-LTF), a Data field, and a PE field.

[0072] Similar to HE SU PPDU 710, HE MU PPDU 720 supports higher spectral efficiency compared to VHT PPDU 330. HE MU PPDU 720 also supports OFDMA. Due to denser subcarrier spacing (as in HE SU PPDU 710), HE MU PPDU 720 allows for payloads of multiple users to be multiplexed in the frequency domain in the Data field. HE MU PPDU 720 supports multiplexing the payload of up to 9 users in a single 20 MHz band. HE MU PPDU 720 has a minimum preamble duration of 47.2 ps, which may increase depending on the number of spatial streams carried by HE MU PPDU 720.

[0073] As shown in FIG. 7, HE MU PPDU 720 includes an L-STF, an L-LTF, an L-SIG, an RL-SIG, an HE-SIG-A, an HE Signal B Field (HE-SIG-B), an HE-STF field, one or more HE-LTF field, a Data field, and a PE field. It is noted that compared to HE SU PPDU 710, HE MU PPDU 720 further includes HE-SIG-B. HE-SIG-B contains indications per STA of RU allocations. A STA may use the indications in HE-SIG-B to locate its payload in HE MU PPDU 720.

[0074] For HE SU PPDU 710 and HE MU PPDU 720, the Gl portion of the HE-LTF and Data field may be one of one of 0.8 ps, 1.6 ps, and 3.2 ps. An AP or STA may use a suitable Gl duration depending on the channel conditions or capability of the target STA or AP.

[0075] For both HE SU PPDU 710 and HE MU PPDU 720, the information portion of the HE-LTF may be one of 3.2 ps, 6.4 ps, or 12.8 ps. Depending on the information portion duration, a subcarrier spacing of the HE-LTF may be one of: 312.5kHz if the information potion is 3.2 ps, 156.25kHz if the information portion is 6.4 ps, and 78.125kHz if the information portion is 12.8 ps. Unlike the HE-LTF, the information portion of the Data field for both HE SU PPDU 710 and HE MU PPDU 720 is always 12.8 ps. Hence, a subcarrier spacing of the Data field is always 78.125kHz corresponding to the duration of the information portion being 12.8 ps. When a 3.2 ps or 6.4 ps long HE-LTF is used by a transmitting STA to transmit HE SU PPDU 710 or HE MU PPDU 720, a receiving STA is required to interpolate the channel estimates to a subcarrier spacing resolution of 78.125kHz to match the subcarrier spacing of the Data field.

[0076] As shown in FIG. 7, HE ER SU PPDU 730 includes an L-STF, an L-LTF, an L-SIG, an RL-SIG, an HE-SIG-A, an HE-STF, one or more HE-LTF, a Data field, and a PE field. It is noted that compared to HE SU PPDU 710, HE ERSU PPDU 730 has an HE-SIG-A that is duplicated in the time domain (16 ps long instead of 8 ps long in HE SU PPDU 710). As such, both L-SIG (duplicated using RL-SIG) and HE-SIG-A are sent in duplicates, which allows a receiving STA to combine the two copies to increase the energy of the received signal. This results in an extended range of reception and increases transmission reliability between the transmitting STA and the receiving STA.

[0077] FIG. 8 illustrates an Extremely High Throughput (EHT) Multi-user (MU) PPDU 800. EHT MU PPDU 800 may be used by STAs conforming to the IEEE 802.11be standard amendment. EHT MU PPDU 800 supports OFDMA up to a bandwidth of 320MHz. EHT MU PPDU 800 can improve spectral efficiency due to support of a higher order modulation compared to other PPDUs (e.g„ HE SU PPDU 710 and HE MU PPDU 720) while supporting the same number of spatialstreams. EHT MU PPDU 800 has a minimum preamble duration of 47.2 ps, which may increase depending on the number of spatial streams carried by EHT MU PPDU 800.

[0078] As shown in FIG. 8, EHT MU PPDU 800 includes an L-STF, an L-LTF, an L-SIG, an RL-SIG, a Universal Signal field (U-SIG), an EHT Signal field (EHT-SIG), an EHT Short Training Field (EHT-STF), one or more EHT Long Training fields (EHT-LTF), a Data field, and a PE field. It is noted that according to the IEEE 802.11 be standard amendment, EHT MU PPDU 800 may be used by a transmitting STA for both SU and MU transmissions.

[0079] The U-SIG is intended to ensure forward compatibility of EHT MU PPDU 800. This means that any future PPDUs that are backward compatible to IEEE 802.11be will contain the same U-SIG field and interpretation. Because of this, IEEE 802.11 be STAs will be able to understand at least in part a PPDU developed in a future amendment.

[0080] The EHT-SIG contains indications per STA of resource unit (RU) allocations. A STA may use the indications in the EHT-SIG to locate its payload in EHT MU PPDU 800.

[0081] The Gl portion of the EHT-LTF and Data fields of EHT MU PPDU 800 may be one of: 0.8 ps, 1.6 ps, or 32 ps. An AP or STA may use a suitable Gl duration depending on the channel conditions or capability of the target STA or AP.

[0082] The information portion of the EHT-LTF maybe one of 3.2 ps, 6.4 ps, or 12.8 ps. Depending on the information portion duration, a subcarrier spacing of the EHT-LTF may be one of: 312.5kHz if the information potion is 3.2 ps, 156.25kHz if the information portion is 6.4 ps, or 78.125kHz if the information portion is 12.8 ps. The information portion of the Data field of EHT MU PPDU 800 is always 12.8 ps. Hence, a subcarrier spacing of the Data field is always 78.125kHz corresponding to the duration of the information portion being 12.8 ps. When a 3.2 ps long or a 6.4 ps long EHT-LTF is used by a transmitting STA to transmit EHT MU PPDU 800, a receiving STA is required to interpolate the channel estimates to a subcarrier spacing resolution of 78.125kHz to match the Data field subcarrier spacing.

[0083] FIG. 9 illustrates an example 900 of a power save (PS) mode. As shown in FIG. 9, example 900 includes STAs 902 and 904. STAs 902 and 904 may each be an AP STA or a non-AP STA. It is assumed that STA 904 implements the PS mode illustrated in FIG. 9, which may be denoted as a dynamic PS mode or a low power listening (LPL) mode.

[0084] In an implementation, a STA (AP STA or non-AP STA) implementing the PS mode illustrated in FIG. 9 may be in a first power state / mode of the PS mode or in a second power state / mode of the PS mode. The first power state / mode may be referred to as a lower capability state / mode, a lower power receive state / mode, or a listen / listening state / mode. The second power state may be referred to as a higher capability state / mode, a higher power receive state / mode, or an awake state / mode. While in the first power state / mode, the STA is capable of receiving PPDUs of a first category. While in the second power state / mode, the STA is capable of receiving PPDUs of the first category and PPDUs of a second category. In an implementation, the STA is not capable of receiving PPDUs of the second category during the first power state / mode. In an implementation, the STA is capable of receiving PPDUs of only the first category during the first power state / mode.

[0085] In an implementation, the first category may include PPDUs having a non-HT PPDU format such as non-HT PPDU 310 described above. In another implementation, the first category may include, additionally or alternatively, PPDUs having a data rate that is less than or equal to 24 Mbps, a bandwidth of 20 MHz, and / or a single spatial stream.The second category may include PPDUs having a format other than the non-HT PPDU format. For example, the second category may include PPDUs having a high throughput (HT) format such as HT mixed mode PPDU 320, a VHT format such as VHT PPDU 330, an HE PPDU such as HE SU PPDU 710, HE MU PPDU 720, or HE ER SU PPDU 730, an EHT PPDU such as EHT MU PPDU 800, an ultra-high reliability (UHR) PPDU, or a physical layer version identifier field. Additionally, or alternatively, the second category may include PPDUs having a data rate that is greater than 24 Mbps, a bandwidth greater than 20 MHz, and / or a plurality of spatial streams.

[0086] The STA may transition between the first power state / mode and the second power state / mode of the PS mode. In an implementation, to reduce the power consumption of the STA, the first power state / mode may correspond to a default state / mode of the PS mode. As such, the STA may operate in the first power state / mode and may transition to the second power state / mode as needed.

[0087] In an implementation, as illustrated in example 900, the STA may transition from the first power state / mode to the second power state / mode in response to being solicited by another STA. For example, as shown in FIG. 9, STA 904, which implements the PS mode, may operate in the first power state / mode and may transition to the second power state / mode in response to a solicitation from STA 902. Specifically, STA 902 may transmit an initial control frame (IGF) 906 to STA 904 requesting that STA 904 transition from the first power state / mode to the second power state / mode of the PS mode. STA 902 may request that STA 904 transition from the first power state / mode to the second power state / mode in order to transmit to STA 904 a PPDU 910 of the second category that STA 904 is not capable of receiving during the first power state / mode (e.g., an EHT PPDU, a PPDU having a bandwidth greater than 20 MHz, and / or a PPDU having multiple spatial streams). In an implementation, ICF 906 may be a request to send (RTS) frame, a multi-user RTS (MU-RTS) frame, or a BlockAck Request (BAR) frame. ICF 906 may be carried in a PPDU of the first category. In an implementation, ICF 906 may be carried in a PPDU using a non-HT duplicate format with a bandwidth of 40 MHz, 80 MHz, 160 MHz or 320 MHz. In an implementation, ICF 906 may include signaling indicating the PPDU bandwidth.

[0088] On receiving ICF 906, STA 904 initiates a transition from the first power state / mode to the second power state / mode. For example, on receiving ICF 906, STA 904 may enable / power on receiver capabilities needed to receive the PPDU of the second category that STA 902 wishes to transmit to STA 904. The transition from the first power state / mode to the second power state / mode may be associated with a state transition duration. The state transition duration may depend on the processing capabilities of STA 904. In an implementation, STA 902 may include padding in ICF 906 to allow STA904 to transition from the first power state / mode to the second power state / mode in a timely manner. Hence, as shown in FIG. 9, STA 904 may start the state transition before the reception of ICF 906 is completed (i.e. without decoding the padding information).

[0089] In an implementation, STA 904 responds to ICF 906 by transmitting an initial control response (ICR) 908 to STA 902. ICR 908 informs STA 902 that STA 904 is transitioning from the first power state / mode to the second power state / mode. In an implementation, as shown in FIG. 9, STA 904 may transmit ICR 908 while transitioning from the first power state / mode to the second power state / mode. In an implementation, STA 904 may transmit ICR 908 after completing the transition from the first power state / mode to the second power state / mode. Completing the transition beforetransmitting ICR 908 may enable STA 904 to perform clear channel assessment over a bandwidth that is higher than 20 MHz. This may enable STA 904 to transmit ICR 908 on idle channels with bandwidths higher than 20 MHz, which improves hidden node protection due to the transmission of ICR 908. In another implementation, STA 904 may transmit ICR 908 before completing the transition to the second power state / mode. In such an implementation, STA 904 may only be able to transmit ICR 908 using a bandwidth of 20 MHz. ICR 908 may be carried in a PPDU of the first category or the second category. In an implementation, STA 904 transmits ICR 908 a short interframe space (SIPS) after receiving ICF 906.

[0090] On receiving ICR 908, STA 902 initiates transmission of PPDU 910. In an implementation, STA 902 transmits PPDU 910 a SIPS after receiving ICR 908. In an implementation, STA 902 may begin transmitting PPDU 910 while STA 904 is still transitioning from the first power state / mode to the second power state / mode. PPDU 910 may thus include a first PPDU part 914 of the first category and a second PPDU part 916 of the second category. In another implementation, STA 902 may begin transmitting PPDU 910 after STA 904 has transitioned to the second power state / mode. PPDU 910 may thus be entirely of the second category.

[0091] After receiving PPDU 910, STA 904 may transmit a BA frame 912 to STA 902. In an implementation, STA 904 may return to the first power state / mode after receiving PPDU 910. STA 904 may transmit BA frame 912 while in the second power state / mode or after returning to the first power state / mode.

[0092] FIG. 10 illustrates an example 1000 of an AP implementation of the PS mode illustrated in FIG. 9. As shown in FIG. 10, example 1000 includes an AP 1002 and a STA 1004. STA 1004 may be associated with AP 1002. It is assumed that AP 1002 implements the PS mode illustrated in FIG. 9. Specifically, as described above, while in the first power state / mode of the PS mode, AP 1002 is capable of receiving PPDUs of a first category; and while in the second power state / mode of the PS mode, AP 1002 is capable of receiving PPDUs of the first category and PPDUs of a second category. The first category and the second category may be as described above with reference to FIG. 10.

[0093] Additionally, AP 1002 may support another mode of operation. The other mode may correspond to an active mode or to a power saving mode different than the PS mode illustrated in FIG. 9. The other mode may have one or more power state / modes. AP 1002 may be capable of receiving PPDUs of the first category and / or of the second category in any power state / mode of the other mode of operation.

[0094] In an implementation, AP 1002 maybe configured to announce a time period during which AP 1002 will operate in the PS mode. For example, as shown in FIG. 10, during a first time period, AP 1002 may transmit a frame 1006 indicating or announcing to other STAs (e.g. STA 1004) or APs (not shown in the figure) a second time period during which AP 1002 will operate in the PS mode. The second time period may or may not be adjacent to the first time period. In an implementation, AP 1002 may be operating in the other mode during the first time period. In another implementation, AP 1002 may be operating in the PS mode during the first time period. Frame 1006 may indicate a start time T1 and an end time T2 of the second time period. Alternatively, frame 1006 may indicate a start time T1 and a duration of the second time period. Alternatively, frame 1006 may indicate that the second time period starts immediately after frame 1006.Similarly, AP 1002 may send another frame (not shown in the figure) during the second time period to indicate the end of the second time period.

[0095] In an example, as shown in FIG. 10, AP 1002 may be in the other mode before switching to the PS mode at the beginning of the second time period. In an implementation, AP 1002 may be configured, upon switching to the PS mode from the other mode, to operate in a default state / mode of the PS mode. In an implementation, the default state / mode may be the first power state / mode as described above. In another example, not shown in FIG. 10, AP 1002 be in the second power state / mode of the PS mode before the beginning of the second time period. AP 1002 may switch from the second power state / mode to the first power state / mode of the PS mode at the beginning of the second time period.

[0096] In an implementation, as illustrated in example 1000, AP 1002 may transition from the first power state / mode to the second power state / mode in response to being solicited by a STA. For example, as shown in FIG. 10, after switching to the PS mode at the beginning of the second time period, AP 1002 may operate in the first power state / mode. Subsequently, AP 1002 receives an ICF 1008 requesting that AP 1002 transition from the first power state / mode to the second power state / mode to receive from STA 1004 a PPDU 1012 of the second category. On receiving ICF 1008 from STA 1004, AP 1002 may respond with an ICR 1010 and may initiate a transition from the first power state / mode to the second power state / mode.

[0097] In an implementation, AP 1002 may determine, from ICF 1008, a TXOP duration, a bandwidth, and / or a modulation and coding scheme (MCS) of PPDU 1012. AP 1002 may turn on / enable receiver capabilities based on the bandwidth and MCS indicated in ICF 1008. In an implementation, STA 1004 may transmit ICF 1008 indicating a TXOP duration and a bandwidth consistent with a TXOP duration and bandwidth to be used for PPDU 1012. For example, PPDU 1012 may have a bandwidth of 80 MHz. In an implementation, STA 1004 may perform a clear channel assessment (CCA) procedure over an 80 MHz bandwidth of the channel to be used for the transmission of PPDU 1012. After a successful CCA procedure, STA 1004 may transmit ICF 1008 to AP 1002 using an 80 MHz non-HT duplicate PPDU with a duration value extending up to the expected BA frame 1014. It is noted that while AP 1002 may only receive a 20 MHz PPDU, it will be able to decode a 20 MHz portion of the 80 MHz non-HT duplicate PPDU carrying ICF 1008. In response to ICF 1008 with an 80 MHz bandwidth indication, STA 1004 may perform a CCA procedure for up to 80 MHz bandwidth for transmitting ICR 1010 if it can transition to the second power state / mode in a timely manner. Transmitting ICR 1010 using a bandwidth of 80 MHz may protect the entire channel to be used by STA 1004 for the transmission of PPDU 1012. In an implementation, ICR 1010 may be a clear to send (CTS) frame carried in a non-HT duplicate PPDU that indicates the channel to be used by STA 1004 for the transmission of PPDU 1012.

[0098] On receiving ICR 1010, STA 1004 initiates transmission of PPDU 1012. In an implementation, STA 1004 transmits PPDU 1012 a SIFS after receiving ICR 1010. After receiving PPDU 1012, AP 1002 may transmit a BA frame 1014 to STA 1004. In an implementation, AP 1002 may return to the first power state / mode after receiving PPDU 1012. AP 1002 may transmit BA frame 1014 while in the second power state / mode or after returning to the first power state / mode. After the second time period, AP 1002 may transition to the other mode of operation or may remain in the first power state / mode of the PS mode.

[0099] FIG. 11 is an example 1100 that illustrates an inefficient STA operation that may occur during the TXS procedure illustrated in Fl Gs. 4 and 5 above. As shown in FIG. 11 , example 1100 includes an AP 1102 and STAs 1104 and 1106. STA 1104 may be associated with AP 1102. In an example, AP 1102 may allocate a portion of an obtained TXOP to STA 1104 by transmitting an MRTT frame 1110. STA 1104 may transmit a CTS frame 1112 to AP 1102 in response to MRTT frame 1110. MRTT frame 1110 may comprise / indicate a TXOP sharing mode subfield, an AID12 subfield set to an AID of STA 1104, and / or a first time period (e.g., X us). In an example, the first time period may indicate the portion of the obtained TXOP allocated by AP 1102 to STA 1104. In an example, the first time period may be indicated by a subfield (e.g., an allocation duration field) of MRTT frame 1110. In an example, the first time period may be set to a value of X us.

[0100] In an example, the TXOP sharing mode subfield may be set to 2. The TXOP sharing mode subfield set to 2 indicates that STA 1104 may transmit one or more non-TB PPDUs to AP 1102 or to a peer STA during the first time period. In an example, the peer STA may be a STA having a connection for P2P communication or direct communication with STA 1104. In an example, the peer STA may be STA 1106. The one or more non-TB PPDUs may comprise a data frame, a control frame, a management frame, or an action frame.

[0101] In example 1100, STA 1104 may use the first time period to transmit one or more non-TB PPDUs to STA 1106 before transmitting one or more non-TB PPDUs to AP 1102. For example, STA 1104 may transmit non-TB PPDUs 1114 and 1118 to STA 1106. STA 1106 may respond to non-TB PPDUs 1114 and 1118 by transmitting respectively BA frames 1116 and 1120 to STA 1104. Subsequently, STA 1104 may transmit non-TB PPDUs 1122 and 1126 to AP 1102. AP 1102 may respond to non-TB PPDUs 1122 and 1126 by transmitting respectively BA frames 1124 and 1128 to STA 1104.

[0102] As shown in FIG. 11, in accordance with the illustrated TXS procedure, AP 1102 remains in an awake power state / mode during the entirety of the first time period allocated to STA 1104. This is despite the fact that AP 1102 is not involved in any communication (with STA 1104 or another STA) while STA 1104 communicates with peer STA 1106. As mentioned above, the awake power state / mode may be a high receive power state / mode (e.g., of a power save mode), in which AP 1102 enables / turns on additional receiver capabilities (e.g., greater receive bandwidth, greater spatial stream reception capacity, higher modulation and coding scheme (MCS), etc.). As such, AP 1102 may inefficiently consume more power than needed to support the TXS procedure.

[0103] Embodiments of the present disclosure, as further described below, address the above-described problem of the existing TXS procedure. In an aspect, an AP may transition from a first power state / mode (e.g., awake state / mode) to a second power state / mode (e.g., listening state / mode) of a power save mode (e.g., dynamic PS mode, TXS based dynamic PS mode, LPL mode, or TXS based LPL mode) before a start of a portion, of a TXOP, allocated by the AP to a first STA or within the portion of the TXOP. The AP may transition, within the portion of the TXOP, from the second power state / mode to the first power state / mode, in response to receiving from the first STA and within the portion of the TXOP, a first frame that causes or requests that the AP transition from the second power state / mode to the first power state / mode. As such, the AP may operate in a lower power state / mode for at least a part of the allocated portion of the TXOP. In another aspect, the AP may transition from the first power state / mode to the second power state / mode within the portion of the TXOP, based on receiving from the STA a first frame indicating that the STA operates, during the portion of theTXOP, according to a transmission mode in which the STA prioritizes frame transmission to the AP over transmission to a peer STA and subsequently receiving from the STA a frame indicating absence of buffered frames for the AP at the STA As such, the AP may operate in a lower power state / mode for at least a remainder of the allocated portion of the TXOP, after the STA has finished frame transmission to the AP.

[0104] FIG. 12 illustrates an example 1200 of an AP power saving operation that may be used in a TXS procedure according to an embodiment. As shown in FIG. 12, example 1200 includes an AP 1202 and STAs 1204 and 1206. STA 1204 may be associated with AP 1202. AP 1202 may support the PS mode as described above in FIG. 9 and / or FIG. 10. Specifically, while operating in the PS mode, AP 1202 may be in a first power state / mode or in a second power state / mode. The first power state / mode may be referred to as a lower power receive state / mode, a lower capability (LC) mode, or a listen / listening state / mode (as illustrated in FIG. 12). The second power state / mode may be referred to as a high power receive state / mode, a higher capability (HC) mode, or an awake state / mode (as illustrated in FIG. 12). Additionally, AP 1202 may support the AP power saving operation described herein. The AP power saving operation may control the operation of AP 1202 in the PS mode (e.g., control when AP 1202 may transition between the first power state / mode and the second power state / mode of the PS mode).

[0105] As shown in FIG. 12, example 1200 may begin with AP 1202 transmitting a frame 1208 that allocates to STA 1204 a portion of a TXOP obtained by AP 1202. Frame 1208 may be an MRTT frame, a trigger frame, ora control frame, for example. STA 1204 may transmit a frame 1210 to AP 1202 in response to frame 1208. Frame 1210 may indicate acceptance by STA 1204 of the allocation of the portion of the TXOP to STA 120. Frame 1210 may be a CTS frame, a modified CTS frame, ora control frame, for example.

[0106] In an embodiment, frame 1208 may comprise an indication of whether AP 1202 enables (or intends to operate according to) the PS mode for the allocated portion of the TXOP. In another embodiment, the indication (or another indication in frame 1208) further indicates whether AP 1202 enables the AP power saving operation described herein for the allocated portion of the TXOP. In an implementation, when the indication indicates that AP 1202 disables the PS mode for the allocated portion of the TXOP, STA 1204 may interpret the indication as indicating that AP 1202 intends to operate according to another mode (another power save mode or an active mode) during the allocated portion of the TXOP. In such a case, the AP power saving operation is considered disabled by STA 1204.

[0107] Frame 1208 may comprise / indicate a TXS mode for the allocated portion of the TXOP. As described in FIGs. 4 and 5 above, the TXS mode may be set to 1 or 2. Frame 1208 may further comprise a first time period that indicates the portion of the TXOP allocated to STA 1204. In an example, the first time period may be set to a value of X us. In an implementation where frame 1208 is an MRTT frame, frame 1208 may include a TXOP Sharing mode subfield, an AID12 subfield, and an Allocation Duration subfield as illustrated in FIG. 3. The TXOP Sharing mode subfield indicates the TXS mode for the allocated portion of the TXOP. The AID12 subfield may be set to an AID of STA 1204 to indicate that the allocation is for STA 1204. The Allocation Duration subfield may indicate the first time period.

[0108] In an embodiment, AP 1202 may enable the PS mode (and the AP power saving operation described herein) for an allocated portion of a TXOP when the TXS mode for the allocated portion of the TXOP is set to 2. For example, inexample 1200, AP 1202 may set the TXS mode to 2 in frame 1208 and may enable the PS mode (and the AP power saving operation) during the first time period corresponding to the portion of the TXOP allocated to STA 1204. AP 1202 may indicate that the PS mode (and the AP power saving operation) is enabled in frame 1208 (or in another frame). The TXS mode set to 2 in frame 1208 indicates that STA 1204 may transmit one or more non-TB PPDUs to AP 1202 or to a peer STA during the first time period. In an example, the peer STA may be a STA having a connection for P2P communication or direct communication with STA 1204. In example 1200, it is assumed that STA 1206 is a peer STA of STA 1204. The one or more non-TB PPDUs may comprise a data frame, a control frame, a management frame, or an action frame.

[0109] In an embodiment, in accordance with the AP power saving operation described herein, when AP 1202 enables the PS mode for a TXS mode 2 allocated portion of a TXOP, AP 1202 may be configured to transition to the first power state / mode (e.g., listening state / mode) before a start of, or within, the allocated portion of the TXOP. AP 1202 may be configured to operate in the first power state / mode and to transition from the first power state / mode to the second power state / mode (e.g., awake state / mode) in response to receiving, from the allocated STA, a frame that requests (or triggers, causes, or indicates) that AP 1202 transition from the first power state / mode to the second power state / mode.

[0110] In an embodiment, AP 1202 may be configured to transition to the first power state / mode after transmitting frame 1208. In an implementation, AP 1202 may be configured to operate in the second power state / mode while transmitting frame 1208 and to transition to the first power state / mode after transmitting frame 1208. In a first implementation (illustrated as Option 1 in FIG. 12), AP 1202 may transition from the second power state / mode to the first power state / mode after transmitting frame 1208 and before the start of the allocated portion of the TXOP. In an embodiment, AP 1202 may receive frame 1210 in response to frame 1208 from STA 1204 while in the first power state / mode. In an embodiment, STA 1204 may transmit frame 1210 in response to frame 1208 to AP 1202 with account to the fact that AP 1202 is in the first power state / mode. For example, STA 1204 may use a non-HT PPDU (e.g., using an MCS of the Basic MCS set (e.g., MCS 0), a single spatial stream, etc.) to transmit frame 1210. In a second implementation (illustrated as Option 2 in FIG. 12), AP 1202 may transition from the second power state / mode to the first power state / mode after transmitting frame 1208 and after the start of the allocated portion of the TXOP. For example, AP 1202 may transition from the second power state / mode to the first power state / mode after receiving frame 1210 from STA 1204. In a third implementation (illustrated as Option 3 in FIG. 12), AP 1202 may transition from the second power state / mode to the first power state / mode after exchanging frames 1208 1210 with STA 1204 and after detecting a first PPDU from STA 1204. For example, AP 1202 may transition from the second power state / mode to the first power state / mode when AP 1202 detects a first PPDU, received from STA 1204 a SIFS after receiving frame 1210 from STA 1204, addressed to a peer STA of STA 1204. In an example, AP 1202 may detect that the first PPDU is addressed to the peer STA when an uplink (UL)Zdownlink (DL) subfield of a universal SIG (U-SIG) of the first PPDU is set to 0. In another example, AP 1202 may detect that the first PPDU is addressed to the peer STA when a receiver address (RA) of a MAC header of the first PPDU does not match a MAC address of AP 1202 or a BSSID of AP 1202.

[0111] In example 1200, STA 1204 may use the first time period to transmit one or more non-TB PPDUs to STA 1206 before transmitting one or more non-TB PPDUs to AP 1202. For example, STA 1204 may transmit non-TB PPDUs 1212 and 1216 to STA 1206. STA 1206 may respond to non-TB PPDUs 1212 and 1216 by transmitting respectively BA frames 1214 and 1218 to STA 1204.

[0112] Subsequently, to transmit the one or more non-TB PPDUs to AP 1202, STA 1204 may be configured to transmit a frame 1220 to AP 1202. Frame 1220 maybe configured to request (or trigger, cause, or indicate) that AP 1202 transition from the first power state / mode to the second power state / mode. Frame 1220 may be an IGF frame, an RTS frame, an MU-RTS frame, a BAR frame, or a buffer status request poll (BSRP) trigger frame. Frame 1220 may be carried in a PPDU of the first category as described above. Accordingly, after transitioning from the second power state / mode to the first power state / mode, AP 1202 may receive frame 1220 while in the first power state / mode and within the portion of the TXOP allocated to STA 1204. AP 1202 may transition from the first power state / mode to the second power state / mode in response to receiving frame 1220. In an implementation, AP 1202 may transmit a frame 1222 to STA 1204 in response to frame 1220. Frame 1222 may comprise an ICR, a CTS frame, a modified CTS frame, an acknowledgment (Ack) frame, or a BlockAck (BA) frame. In an implementation, AP 1202 may transition from the first power state / mode to the second power state / mode after transmitting frame 1222. In another embodiment, the mechanism of frames 1220 and 1222 may be replaced with STA 1204 transmitting to AP 1202 a data frame comprised in a PPDU of the first category, as described below with reference to FIG. 15.

[0113] STA 1204 may then transmit non-TB PPDUs 1224 and 1228 to AP 1202. AP 1202 may respond to non-TB PPDUs 1224 and 1228 by transmitting respectively BA frames 1226 and 1230 to STA 1204. Non-TB PPDUs 1224 and 1228 may be PPDUs of the first category or the second category as described above.

[0114] In an embodiment (not shown in FIG. 12), AP 1202 may receive from STA 1204 a first frame indicating whether STA 1204 supports the PS mode illustrated in FIG. 9 and / or FIG. 10. The first frame may be an association request frame, a probe request frame, a management frame, an action frame, or a control frame. In an implementation, STA 1204 supporting the PS mode comprises STA 1204 being able to transmit, to AP 1202, frame 1220 before transmitting, to AP 1202, a further frame (e.g„ non-TB PPDUs 1224 and 1228) within the portion of the TXOP allocated to STA 1204.

[0115] In an embodiment (not shown in FIG. 12), AP 1202 may transmit to STA 1204 a second frame indicating whether AP 1202 supports the PS mode illustrated in FIG. 9 and / or FIG. 10 and the AP power saving operation described herein. The second frame may be a beacon frame, an association response frame, a probe response frame, or a control frame. AP 1202 may transmit the second frame in response to the first frame from STA 1204. In an implementation, AP 1202 supporting the PS mode comprises AP 1202 being able to transition to the first power state / mode within the portion of the TXOP allocated to STA 1204.

[0116] FIG. 13 illustrates an example 1300 of an AP power saving operation that may be used in a TXS procedure according to an embodiment. As shown in FIG. 13, example 1300 includes an AP 1302 and STAs 1304 and 1306. STA 1304 may be associated with AP 1302. AP 1302 may support the PS mode as described above in FIG. 9 and / or FIG. 10. Specifically, while operating in the PS mode, AP 1302 may be in a first power state / mode or in a second powerstate / mode. The first power state / mode may be referred to as a lower power receive state / mode or a listen / listening state / mode (as illustrated in FIG. 13). The second power state / mode may be referred to as a high power receive state / mode or an awake state / mode (as illustrated in FIG. 13). Additionally, AP 1302 may support the AP power saving operation described herein. The AP power saving operation may control the operation of AP 1302 in the PS mode (e.g., control when AP 1302 may transition between the first power state / mode and the second power state / mode of the PS mode).

[0117] As shown in FIG. 13, example 1300 may begin with AP 1302 transmitting a frame 1308 that allocates to STA 1304 a portion of a TXOP obtained by AP 1302. Frame 1308 maybe an MRTT frame, an ICF, a trigger frame, ora control frame, for example. STA 1304 may transmit a frame 1310 to AP 1302 in response to frame 1308. Frame 1310 may indicate acceptance by STA 1304 of the allocation of the portion of the TXOP to STA 1304. Frame 1310 may be a CTS frame, a modified CTS frame, or a control frame, for example.

[0118] In an embodiment, frame 1308 may comprise an indication of whether AP 1302 enables (or intends to operate according to) the PS mode for the allocated portion of the TXOP. In another embodiment, the indication (or another indication in frame 1308) further indicates whether AP 1302 enables the AP power saving operation described herein for the allocated portion of the TXOP. In an implementation, when the indication indicates that AP 1302 disables the PS mode for the allocated portion of the TXOP, STA 1304 may interpret the indication as indicating that AP 1302 intends to operate according to another mode (another power save mode or an active mode) during the allocated portion of the TXOP. In such a case, the AP power saving operation is considered disabled by STA 1304.

[0119] Frame 1308 may comprise / indicate a TXS mode for the allocated portion of the TXOP. As described in FIGs. 4 and 5 above, the TXS mode may be set to 1 or 2. Frame 1308 may further comprise a first time period that indicates the portion of the TXOP allocated to STA 1304. In an example, the first time period may be set to a value of X us. In an implementation where frame 1308 is an MRTT frame, frame 1308 may include a TXOP Sharing mode subfield, an AID12 subfield, and an Allocation Duration subfield as illustrated in FIG. 3. The TXOP Sharing mode subfield indicates the TXS mode for the allocated portion of the TXOP. The AID12 subfield may be set to an AID of STA 1304 to indicate that the allocation is for STA 1304. The Allocation Duration subfield may indicate the first time period.

[0120] In an embodiment, AP 1302 may enable the PS mode (and the AP power saving operation described herein) for an allocated portion of a TXOP when the TXS mode for the allocated portion of the TXOP is set to 2. For example, in example 1300, AP 1302 may set the TXS mode to 2 in frame 1308 and may enable the PS mode (and the AP power saving operation) during the first time period corresponding to the portion of the TXOP allocated to STA 1304. AP 1302 may indicate that the PS mode (and the AP power saving operation) is enabled in frame 1308 (or in another frame). The TXS mode set to 2 in frame 1308 indicates that STA 1304 may transmit one or more non-TB PPDUs to AP 1302 or to a peer STA during the first time period. In an example, the peer STA may be a STA having a connection for P2P communication or direct communication with STA 1304. In example 1300, it is assumed that STA 1306 is a peer STA of STA 1304. The one or more non-TB PPDUs may comprise a data frame, a control frame, a management frame, or an action frame.

[0121] In an embodiment, STA 1304 may indicate, e.g., in frame 1310, whether STA 1304 operates or intends to operate in a first transmission mode during the portion of the TXOP allocated to STA 1304. In an implementation, the first transmission mode may correspond to a transmission mode in which STA 1304 prioritizes transmission to a peer STA, e.g., STA 1306, over transmission to AP 1302, during the portion of the TXOP allocated to STA 1304. In another implementation, the first transmission mode may correspond to a transmission mode in which STA 1304 transmits, during the portion of the TXOP allocated to STA 1304, first buffered frames for a peer STA, e.g., STA 1306, before transmitting second buffered frames for AP 1302. That is, STA 1304 may first exhaust transmission of the first buffered frames for the peer STA before beginning to transmit the second buffered frames for AP 1302. In an embodiment, the first transmission mode may be included in a frame separate from frame 1310. For example, STA 1304 may transmit, to AP 1302, a frame comprising the first transmission mode between frame 1310 and non-TB PPDU 1312 (e.g., a SIFS after frame 1310 and a SIFS before non-TB PPDU 1312).

[0122] In an embodiment, in accordance with the AP power saving operation described herein, when AP 1302 enables the PS mode for a TXS mode 2 allocated portion of a TXOP, AP 1302 may be configured to transition to the first power state / mode (e.g., listening state / mode) before a start of, or within, the allocated portion of the TXOP. AP 1302 may be configured to operate in the first power state / mode and to transition from the first power state / mode to the second power state / mode (e.g., awake state / mode) in response to receiving, from the allocated STA, a frame that requests (or triggers, causes, or indicates) that AP 1302 transition from the first power state / mode to the second power state / mode.

[0123] In an embodiment, AP 1302 may be configured to transition to the first power state / mode after transmitting frame 1308. In an implementation, AP 1302 may be configured to operate in the second power state / mode while transmitting frame 1308 and to transition to the first power state / mode after transmitting frame 1308. In a first implementation (illustrated as Option 1 in FIG. 13), AP 1302 may transition from the second power state / mode to the first power state / mode after transmitting frame 1308 and before the start of the allocated portion of the TXOP. In an implementation, in response to frame 1310 indicating that STA 1304 operates in the first transmission mode during the allocated portion of the TXOP, AP 1302 maintains operation in the first power state / mode. AP 1302 may maintain operation in the first power state / mode or may transition from the first power state / mode to the second power state / mode, in response to frame 1310 indicating that STA 1304 does not operate according to the first transmission mode during the allocated portion of the TXOP. In an embodiment, AP 1302 may receive frame 1310 in response to frame 1308 from STA 1304 while in the first power state / mode. In an embodiment, STA 1304 may transmit frame 1310 in response to frame 1308 to AP 1302 with account to the fact that AP 1302 is in the first power state / mode. For example, STA 1304 may use a non-HT PPDU (e g., using an MCS of the Basic MCS set (e.g., MCS 0), a single spatial stream, etc ) to transmit frame 1310. In a second implementation (illustrated as Option 2 in FIG. 13), AP 1302 may transition from the second power state / mode to the first power state / mode after transmitting frame 1308 and after the start of the allocated portion of the TXOP. For example, AP 1302 may transition from the second power state / mode to the first power state / mode after receiving frame 1310 from STA 1304. In an implementation, AP 1302 may transition from the second power state / mode to the first power state / mode in response to frame 1310 indicating that STA 1304 operates in the according to the first transmission mode during theallocated portion of the TXOP. AP 1302 may maintain operation in the second power state / mode or may transition from the second power state / mode to the first power state / mode, in response to frame 1310 indicating that STA 1304 does not operate according to the first transmission mode during the allocated portion of the TXOP. In a third implementation (illustrated as Option 3 in FIG. 13), AP 1302 may transition from the second power state / mode to the first power state / mode after exchanging frames 1308 and 1310 with STA 1304 and after detecting a first PPDU from STA 1304. For example, AP 1302 may transition from the second power state / mode to the first power state / mode when AP 1302 detects a first PPDU, received from STA 1304 a SIFS after receiving frame 1310 from STA 1204, addressed to a peer STA of STA 1304. In an example, AP 1302 may detect that the first PPDU is addressed to the peer STA when an uplink (UL)Zdownlink (DL) subfield of a universal SIG (U-SIG) of the first PPDU is set to 0. In another example, AP 1302 may detect that the first PPDU is addressed to the peer STA when a receiver address (RA) of a MAC header of the first PPDU does not match a MAC address of AP 1302 or a BSSID of AP 1302.

[0124] In example 1300, STA 1304 may use the first time period to transmit one or more non-TB PPDUs to STA 1306 before transmitting one or more non-TB PPDUs to AP 1302. For example, STA 1304 may transmit non-TB PPDUs 1312 and 1316 to STA 1306. STA 1306 may respond to non-TB PPDUs 1312 and 1316 by transmitting BA frames 1314 and 1318 respectively to STA 1304.

[0125] Subsequently, to transmit the one or more non-TB PPDUs to AP 1302, STA 1304 may be configured to transmit a frame 1320 to AP 1302. Frame 1320 maybe configured to request (or trigger, cause, or indicate) that AP 1302 transition from the first power state / mode to the second power state / mode. Frame 1320 may be an ICF frame, an RTS frame, an MU-RTS frame, a BAR frame, or a buffer status request poll (BSRP) trigger frame. Frame 1320 may be carried in a PPDU of the first category as described above. Accordingly, after transitioning from the second power state / mode to the first power state / mode, AP 1302 may receive frame 1320 while in the first power state / mode and within the portion of the TXOP allocated to STA 1304. AP 1302 may transition from the first power state / mode to the second power state / mode in response to receiving frame 1320. In an implementation, AP 1302 may transmit a frame 1322 to STA 1304 in response to frame 1320. Frame 1322 may comprise an ICR, a CTS frame, a modified CTS frame, an acknowledgment (Ack) frame, or a BlockAck (BA) frame. In an implementation, AP 1302 may transition from the first power state / mode to the second power state / mode after transmitting frame 1322. In another embodiment, the mechanism of frames 1320 and 1322 may be replaced with STA 1304 transmitting to AP 1302 a data frame comprised in a PPDU of the first category, as described below with reference to FIG. 15.

[0126] STA 1304 may then transmit non-TB PPDUs 1324 and 1328 to AP 1302. AP 1302 may respond to non-TB PPDUs 1324 and 1328 by transmitting BA frames 1326 and 1330 respectively to STA 1304. Non-TB PPDUs 1324 and 1328 may be PPDUs of the first category or the second category as described above.

[0127] In an embodiment (not shown in FIG. 13), AP 1302 may receive from STA 1304 a first frame indicating whether STA 1304 supports the PS mode illustrated in FIG. 9 and / or FIG. 10. The first frame may be an association request frame, a probe request frame, a management frame, an action frame, or a control frame. In an implementation, STA 1304supporting the PS mode comprises STA 1304 being able to transmit, to AP 1302, frame 1320 before transmitting, to AP 1302, a further frame (e.g„ non-TB PPDUs 1324 and 1328) within the portion of the TXOP allocated to STA 1304.

[0128] In an embodiment (not shown in FIG. 13), AP 1302 may transmit to STA 1304 a second frame indicating whether AP 1302 supports the PS mode illustrated in FIG. 9 and / or FIG. 10 and the AP power saving operation described herein. The second frame may be a beacon frame, an association response frame, a probe response frame, a management frame, an action frame, or a control frame. AP 1302 may transmit the second frame in response to the first frame from STA 1304. In an implementation, AP 1302 supporting the PS mode comprises AP 1302 being able to transition to the first power state / mode within the portion of the TXOP allocated to STA 1304.

[0129] FIG. 14 illustrates an example 1400 of an AP power saving operation that may be used in a TXS procedure according to an embodiment. As shown in FIG. 14, example 1400 includes an AP 1402 and STAs 1404 and 1406. STA 1404 may be associated with AP 1402. AP 1402 may support the PS mode as described above in FIG. 9 and / or FIG. 10. Specifically, while operating in the PS mode, AP 1402 may be in a first power state / mode or in a second power state / mode. The first power state / mode may be referred to as a lower power receive state / mode or a listen / listening state / mode (as illustrated in FIG. 14). The second power state / mode may be referred to as a high power receive state / mode or an awake state / mode (as illustrated in FIG. 14). Additionally, AP 1402 may support the AP power saving operation described herein. The AP power saving operation may control the operation of AP 1402 in the PS mode (e.g„ control when AP 1402 may transition between the first power state / mode and the second power state / mode of the PS mode).

[0130] As shown in FIG. 14, example 1400 may begin with AP 1402 transmitting a frame 1408 that allocates to STA 1404 a portion of a TXOP obtained by AP 1402. Frame 1408 may be an MRTT frame, a trigger frame, or a control frame, for example. STA 1404 may transmit a frame 1410 to AP 1402 in response to frame 1408. Frame 1410 may indicate acceptance by STA 1404 of the allocation of the portion of the TXOP to STA 1404. Frame 1410 maybe a CTS frame, a modified CTS frame, ora control frame, for example.

[0131] In an embodiment, frame 1408 may comprise an indication of whether AP 1402 enables (or intends to operate according to) the PS mode for the allocated portion of the TXOP. In another embodiment, the indication (or another indication in frame 1408) further indicates whether AP 1402 enables the AP power saving operation described herein for the allocated portion of the TXOP. In an implementation, when the indication indicates that AP 1402 disables the PS mode for the allocated portion of the TXOP, STA 1404 may interpret the indication as indicating that AP 1402 intends to operate according to another mode (another power save mode or an active mode) during the allocated portion of the TXOP. In such a case, the AP power saving operation is considered disabled by STA 1404.

[0132] Frame 1408 may comprise / indicate a TXS mode for the allocated portion of the TXOP. As described in FIGs. 4 and 5 above, the TXS mode may be set to 1 or 2. Frame 1408 may further comprise a first time period that indicates the portion of the TXOP allocated to STA 1404. In an example, the first time period may be set to a value of X us. In an implementation where frame 1408 is an MRTT frame, frame 1408 may include a TXOP Sharing mode subfield, an AID12 subfield, and an Allocation Duration subfield as illustrated in FIG. 3. The TXOP Sharing mode subfield indicates the TXSmode for the allocated portion of the TXOP. The AID12 subfield may be set to an AID of STA 1404 to indicate that the allocation is for STA 1404. The Allocation Duration subfield may indicate the first time period.

[0133] In an embodiment, AP 1402 may enable the PS mode (and the AP power saving operation described herein) for an allocated portion of a TXOP when the TXS mode for the allocated portion of the TXOP is set to 2. For example, in example 1400, AP 1402 may set the TXS mode to 2 in frame 1408 and may enable the PS mode (and the AP power saving operation) during the first time period corresponding to the portion of the TXOP allocated to STA 1404. AP 1402 may indicate that the PS mode (and the AP power saving operation) is enabled in frame 1408 (or in another frame). The TXS mode set to 2 in frame 1408 indicates that STA 1404 may transmit one or more non-TB PPDUs to AP 1402 or to a peer STA during the first time period. In an example, the peer STA may be a STA having a connection for P2P communication or direct communication with STA 1404. In example 1400, it is assumed that STA 1406 is a peer STA of STA 1404. The one or more non-TB PPDUs may comprise a data frame, a control frame, a management frame, or an action frame.

[0134] In an embodiment, AP 1402 may indicate in frame 1408 or in another frame (not shown in FIG. 14) a transmission mode to be used by STA 1404 during the allocated portion of the TXOP. In an embodiment, the transmission mode may correspond to a first transmission mode in which STA 1404 prioritizes transmission to AP 1402 over transmission to a peer STA, e.g,, STA 1406, during the allocated portion of the TXOP. In another implementation, the transmission mode may correspond to a first transmission mode in which STA 1404 transmits, during the portion of the TXOP allocated to STA 1404, first buffered frames for AP 1402 before transmitting second buffered frames for a peer STA, e.g., STA 1406. That is, STA 1404 may first exhaust transmission of the first buffered frames for AP 1402 before beginning to transmit the second buffered frames for STA 1406. In another embodiment, the transmission mode may correspond to a second transmission mode in which STA 1404 prioritizes transmission to a peer STA, e.g., STA 1406 over transmission to AP 1402, during the allocated portion of the TXOP. In another implementation, the transmission mode may correspond to a second transmission mode in which STA 1404 transmits, during the portion of the TXOP allocated to STA 1404, first buffered frames fora peer STA, e.g., STA 1406 before transmitting second buffered frames for AP 1402. That is, STA 1404 may first exhaust transmission of the first buffered frames for STA 1406 before beginning to transmit the second buffered frames for AP 1402. In an embodiment, STA 1404 may indicate acceptance of the transmission mode in frame 1410 or in another frame transmitted to AP 1402.

[0135] In an embodiment, in accordance with the AP power saving operation described herein, when AP 1402 enables the PS mode fora TXOP portion allocated according to TXS mode 2, AP 1402 maybe configured to transition to the first power state / mode (e.g., listening state / mode) before a start of, or within, the allocated portion of the TXOP. In an embodiment, the transitioning by AP 1402 to the first power state / mode may further be based on the transmission mode of STA 1404 indicated in frame 1408 or in another frame.

[0136] In an embodiment (illustrated as Option 1 in FIG. 14), AP 1402 maybe configuredtotransition to the first power state / mode after transmitting frame 1408. In an embodiment (shown in FIG. 14), based on frame 1408 indicating that STA 1404 is to operate in the first transmission mode and STA 1404 accepting the first transmission mode in frame 1410,AP 1402 may transition from the first power state / mode to the second power state / mode after receiving frame 1410. In an embodiment (not shown in FIG. 14), based on frame 1408 indicating that STA 1404 is to operate in the first transmission mode and STA 1404 rejecting the first transmission mode in frame 1410, AP 1402 may maintain its operation in the first power state / mode after receiving frame 1410. In another embodiment (not shown in FIG. 14), based on frame 1408 indicating that STA 1404 is to operate in the second transmission mode and STA 1404 accepting the second transmission mode in frame 1410, AP 1402 may maintain its operation in the first power state / mode after receiving frame 1410. In another embodiment (not shown in FIG. 14), based on frame 1408 indicating that STA 1404 is to operate in the second transmission mode and STA 1404 rejecting the second transmission mode in frame 1410, AP 1402 may transition from the first power state / mode to the second power state / mode after receiving frame 1410.

[0137] In another embodiment (illustrated as Option 2 in FIG. 14), AP 1402 may be configured to maintain operation in the second power state / mode after transmitting frame 1408. In an embodiment (shown in FIG. 14), based on frame 1408 indicating that STA 1404 is to operate in the first transmission mode and STA 1404 accepting the first transmission mode in frame 1410, AP 1402 may maintain its operation in the second power state / mode after receiving frame 1410. In an embodiment (not shown in FIG. 14), based on frame 1408 indicating that STA 1404 is to operate in the first transmission mode and STA 1404 rejecting the first transmission mode in frame 1410, AP 1402 may transition to the first power state / mode after receiving frame 1410. In another embodiment (not shown in FIG. 14), based on frame 1408 indicating that STA 1404 is to operate in the second transmission mode and STA 1404 accepting the second transmission mode in frame 1410, AP 1402 may transition from the first second power state / mode to the first power state / mode after receiving frame 1410. In another embodiment (not shown in FIG. 14), based on frame 1408 indicating that STA 1404 is to operate in the second transmission mode and STA 1404 rejecting the second transmission mode in frame 1410, AP 1402 may maintain its operation in the second power state / mode after receiving frame 1410.

[0138] In example 1400, frame 1408 may indicate that STA 1404 is to operate in the first transmission mode during the allocated portion of the TXOP. STA 1404 may accept the first transmission mode in frame 1410. Accordingly, AP 1402 may transition to the second power state / mode after receiving frame 1410 (Option 1) or may maintain operation in the second power state / mode after receiving frame 1410 (Option 2). STA 1404 may use the first time period to transmit one or more non-TB PPDUs to AP 1402 before transmitting one or more non-TB PPDUs to STA 1406. For example, STA 1404 may transmit non-TB PPDUs 1412 and 1416 to AP 1402. Non-TB PPDUs 1412 and 1416 may be PPDUs of the first category or the second category as described above. AP 1402 may respond to non-TB PPDUs 1412 and 1416 by transmitting BA frames 1414 and 1418 respectively to STA 1404. In an embodiment, STA 1404 maybe configured to set to zero a “more data” field of a last PPDU that STA 1404 intends to transmit to AP 1402. For example, STA 1404 may set to zero the “more data” field of non-TB PPDU 1416. This indicates to AP 1402 that STA 1404 exhausted with non-TB PPDU 1416 transmission of its buffered frames for AP 1402. As such, AP 1402 may transition to the first power state / mode after receiving non-TB PPDU 1416. In an implementation, AP 1402 may transition to the first power state / mode after transmitting BA frame 1418 in response to non-TB PPDU 1416.

[0139] STA 1404 may then transmit non-TB PPDUs 1420 and 1424 to STA 1406. STA 1406 may respond to non-TB PPDUs 1420 and 1424 by transmitting respectively BA frames 1422 and 1426 to STA 1404.

[0140] In an embodiment (not shown in FIG. 14), AP 1402 may receive from STA 1404 a first frame indicating whether STA 1404 supports the PS mode illustrated in FIG. 9 and / or FIG. 10. The first frame may be an association request frame, a probe request frame, or a control frame. In an implementation, STA 1404 supporting the PS mode comprises STA 1404 being able to transmit, to AP 1402, PPDU 1420 before transmitting, to AP 1402, a further frame (e.g., non-TB PPDUs 1424 and 1428) within the portion of the TXOP allocated to STA 1404.

[0141] In an embodiment (not shown in FIG. 14), AP 1402 may transmit to STA 1404 a second frame indicating whether AP 1402 supports the PS mode illustrated in FIG. 9 and / or FIG. 10 and the AP power saving operation described herein. The second frame may be a beacon frame, an association response frame, a probe response frame, or a control frame. AP 1402 may transmit the second frame in response to the first frame from STA 1404. In an implementation, AP 1402 supporting the PS mode comprises AP 1402 being able to transition to the first power state / mode within the portion of the TXOP allocated to STA 1404.

[0142] FIG. 15 illustrates an example 1500 of an AP power saving operation that may be used in a TXS procedure according to an embodiment. As shown in FIG. 15, example 1500 includes an AP 1502 and STAs 1504 and 1506. STA 1504 may be associated with AP 1502. AP 1502 may support the PS mode as described above in FIG. 9 and / or FIG. 10. Specifically, while operating in the PS mode, AP 1502 may be in a first power state / mode or in a second power state / mode. The first power state / mode may be referred to as a lower power receive state / mode or a listen / listening state / mode (as illustrated in FIG. 15). The second power state / mode may be referred to as a high power receive state / mode or an awake state / mode (as illustrated in FIG. 15). Additionally, AP 1502 may support the AP power saving operation described herein. The AP power saving operation may control the operation of AP 1502 in the PS mode (e.g., control when AP 1502 may transition between the first power state / mode and the second power state / mode of the PS mode).

[0143] As shown in FIG. 15, example 1500 may begin with AP 1502 transmitting a frame 1508 that allocates to STA 1504 a portion of a TXOP obtained by AP 1502. Frame 1508 may be an MRTT frame, a trigger frame, or a control frame, for example. STA 1504 may transmit a frame 1510 to AP 1502 in response to frame 1508. Frame 1510 may indicate acceptance by STA 1504 of the allocation of the portion of the TXOP to STA 1504. Frame 1510 may be a CTS frame, a modified CTS frame, ora control frame, for example.

[0144] In an embodiment, frame 1508 may comprise an indication of whether AP 1502 enables (or intends to operate according to) the PS mode for the allocated portion of the TXOP. In another embodiment, the indication (or another indication in frame 1508) further indicates whether AP 1502 enables the AP power saving operation described herein for the allocated portion of the TXOP. In an implementation, when the indication indicates that AP 1502 disables the PS mode for the allocated portion of the TXOP, STA 1504 may interpret the indication as indicating that AP 1502 intends to operate according to another mode (another power save mode or an active mode) during the allocated portion of the TXOP. In such a case, the AP power saving operation is considered disabled by STA 1504.

[0145] Frame 1508 may comprise / indicate a TXS mode for the allocated portion of the TXOP. As described in FIGs. 4 and 5 above, the TXS mode may be set to 1 or 2. Frame 1508 may further comprise a first time period that indicates the portion of the TXOP allocated to STA 1504. In an example, the first time period may be set to a value of X us. In an implementation where frame 1508 is an MRTT frame, frame 1508 may include a TXOP Sharing mode subfield, an AID12 subfield, and an Allocation Duration subfield as illustrated in FIG. 3. The TXOP Sharing mode subfield indicates the TXS mode for the allocated portion of the TXOP. The AID12 subfield may be set to an AID of STA 1504 to indicate that the allocation is for STA 1504. The Allocation Duration subfield may indicate the first time period.

[0146] In an embodiment, AP 1502 may enable the PS mode (and the AP power saving operation described herein) for an allocated portion of a TXOP when the TXS mode for the allocated portion of the TXOP is set to 2. For example, in example 1500, AP 1502 may set the TXS mode to 2 in frame 1508 and may enable the PS mode (and the AP power saving operation) during the first time period corresponding to the portion of the TXOP allocated to STA 1504. AP 1502 may indicate that the PS mode (and the AP power saving operation) is enabled in frame 1508 (or in another frame). The TXS mode set to 2 in frame 1508 indicates that STA 1504 may transmit one or more non-TB PPDUs to AP 1502 or to a peer STA during the first time period. In an example, the peer STA may be a STA having a connection for P2P communication or direct communication with STA 1504. In example 1500, it is assumed that STA 1506 is a peer STA of STA 1504. The one or more non-TB PPDUs may comprise a data frame, a control frame, a management frame, or an action frame.

[0147] In an embodiment, in accordance with the AP power saving operation described herein, when AP 1502 enables the PS mode for a TXS mode 2 allocated portion of a TXOP, AP 1502 may be configured to transition to the first power state / mode (e.g„ listening state / mode) before a start of, or within, the allocated portion of the TXOP. AP 1502 may be configured to operate in the first power state / mode and to transition from the first power state / mode to the second power state / mode (e.g., awake state / mode) in response to receiving, from the allocated STA, a frame that requests (or triggers, causes, or indicates) that AP 1502 transition from the first power state / mode to the second power state / mode.

[0148] In an embodiment, AP 1502 may be configured to transition to the first power state / mode after transmitting frame 1508. In an implementation, AP 1502 may be configured to operate in the second power state / mode while transmitting frame 1508 and to transition to the first power state / mode after transmitting frame 1508. In a first implementation (illustrated as Option 1 in FIG. 15), AP 1502 may transition from the second power state / mode to the first power state / mode after transmitting frame 1508 and before the start of the allocated portion of the TXOP. In a second implementation (illustrated as Option 2 in FIG. 15), AP 1502 may transition from the second power state / mode to the first power state / mode after transmitting frame 1508 and after the start of the allocated portion of the TXOP. For example, AP 1502 may transition from the second power state / mode to the first power state / mode after receiving frame 1510 from STA 1504. In a third implementation (illustrated as Option 3 in FIG. 15), AP 1502 may transition from the second power state / mode to the first power state / mode after exchanging frames 1508 and 1510 with STA 1504 and after detecting a first PPDU from STA 1504. For example, AP 1502 may transition from the second power state / mode to the first power state / mode when AP 1502 detects a first PPDU, received from STA 1504 a SIFS after receiving frame 1510 from STA1504, addressed to a peer STA of STA 1504. In an example, AP 1502 may detect that the first PPDU is addressed to the peer STA when an uplink (UL)Zdownlink (DL) subfield of a universal SIG (U-SIG) of the first PPDU is set to 0. In another example, AP 1502 may detect that the first PPDU is addressed to the peer STA when a receiver address (RA) of a MAC header of the first PPDU does not match a MAC address of AP 1502 ora BSSID of AP 1502.

[0149] In example 1500, STA 1504 may use the first time period to transmit one or more non-TB PPDUs to STA 1506 before transmitting one or more non-TB PPDUs to AP 1502. For example, STA 1504 may transmit non-TB PPDUs 1512 and 1516 to STA 1506. STA 1506 may respond to non-TB PPDUs 1512 and 1516 by transmitting respectively BA frames 1514 and 1518 to STA 1504.

[0150] Subsequently, to transmit the one or more non-TB PPDUs to AP 1502, STA 1504 may be configured to transmit a PPDU 1520 to AP 1502. PPDU 1520 may be a PPDU of the first category that carries a data frame. PPDU 1520 may be configured to trigger AP 1502 to transition from the first power state / mode to the second power state / mode.

[0151] AP 1502 may be configured, on receiving while in the first power state / mode a PPDU of the first category that carries a data frame, to transition from the first power state / mode to the second power state / mode. As such, on receiving PPDU 1520 from STA 1504, AP 1502 may transition from the first power state / mode to the second power state / mode. In an embodiment, AP 1502 may transmit a BA frame 1522 to STA 1504 in response to PPDU 1520. In an embodiment, AP 1502 may transition from the first power state / mode to the second power state / mode after transmitting BA frame 1522.

[0152] STA 1504 may then transmit non-TB PPDU 1524 to AP 1502. AP 1502 may respond to non-TB PPDU 1524 by transmitting a BA frame 1526 to STA 1504. Non-TB PPDU 1524 may be a PPDU of the first category or the second category as described above.

[0153] In another embodiment (not shown in FIG. 15), PPDU 1520 may indicate whether AP 1502 is requested to transition to the second power state / mode after receiving PPDU 1520. For example, where STA 1504 has no buffered frames for AP 1502 to transmit to AP 1502 after transmitting PPDU 1520, PPDU 1520 may indicate that AP 1502 may maintain the first power state / mode after receiving PPDU 1520. Based on PPDU 1520 indicating that AP 1502 may maintain the first power state / mode, AP may maintain the first power state / mode after receiving PPDU 1520. In another example, where STA 1504 has buffered frames for AP 1502 to transmit to AP 1502 after transmitting PPDU 1520, PPDU 1520 may indicate that AP 1502 is to transition to the second power state / mode after receiving PPDU 1520. Based on PPDU 1520 indicating that AP 1502 is to transition to the second power state / mode, AP may transition from the first power state / mode to the second power state / mode after receiving PPDU 1520.

[0154] In an embodiment (not shown in FIG. 15), AP 1502 may receive from STA 1504 a first frame indicating whether STA 1504 supports the PS mode illustrated in FIG.9 and / or FIG. 10. The first frame may be an association request frame, a probe request frame, or a control frame. In an implementation, STA 1504 supporting the PS mode comprises STA 1504 being able to transmit, to AP 1502, PPDU 1520 before transmitting, to AP 1502, a further frame (e.g., non-TB PPDUs 1524 and 1528) within the portion of the TXOP allocated to STA 1504.

[0155] In an embodiment (not shown in FIG. 15), AP 1502 may transmit to STA 1504 a second frame indicating whether AP 1502 supports the PS mode illustrated in FIG. 9 and / or FIG. 10 and the AP power saving operation described herein.The second frame may be a beacon frame, an association response frame, a probe response frame, or a control frame. AP 1502 may transmit the second frame in response to the first frame from STA 1504. In an implementation, AP 1502 supporting the PS mode comprises AP 1502 being able to transition to the first power state / mode within the portion of the TXOP allocated to STA 1504.

[0156] In an embodiment (not shown in FIG. 15), AP 1502 may receive from STA 1504 a first frame indicating whether STA 1504 supports the PS mode illustrated in FIG. 9 and / or FIG. 10. The first frame may be an association request frame, a probe request frame, or a control frame. In an implementation, STA 1504 supporting the PS mode comprises STA 1504 being able to transmit, to AP 1502, PPDU 1520 before transmitting, to AP 1502, a further frame (e.g., non-TB PPDUs 1524 and 1528) within the portion of the TXOP allocated to STA 1504.

[0157] In an embodiment (not shown in FIG. 15), AP 1502 may transmit to STA 1504 a second frame indicating whether AP 1502 supports the PS mode illustrated in FIG. 9 and / or FIG. 10 and the AP power saving operation described herein. The second frame may be a beacon frame, an association response frame, a probe response frame, or a control frame. AP 1502 may transmit the second frame in response to the first frame from STA 1504. In an implementation, AP 1502 supporting the PS mode comprises AP 1502 being able to transition to the first power state / mode within the portion of the TXOP allocated to STA 1504.

[0158] FIG. 16 illustrates an example 1600 of an AP power saving operation that may be used in a TXS procedure according to an embodiment. As shown in FIG. 16, example 1600 includes an AP 1602 and STAs 1604 and 1606. STA 1604 may be associated with AP 1602. AP 1602 may support the PS mode as described above in FIG. 9 and / or FIG. 10. Specifically, while operating in the PS mode, AP 1602 may be in a first power state / mode or in a second power state / mode. The first power state / mode may be referred to as a lower power receive state / mode or a listen / listening state / mode (as illustrated in FIG. 16). The second power state / mode may be referred to as a high power receive state / mode or an awake state / mode (as illustrated in FIG. 16). Additionally, AP 1602 may support the AP power saving operation described herein. The AP power saving operation may control the operation of AP 1602 in the PS mode (e.g., control when AP 1602 may transition between the first power state / mode and the second power state / mode of the PS mode).

[0159] As shown in FIG. 16, example 1600 may begin with AP 1602 transmitting a frame 1608 that allocates to STA 1604 a portion of a TXOP obtained by AP 1602. Frame 1608 may be an MRTT frame, a trigger frame, ora control frame, for example. STA 1604 may transmit a frame 1610 to AP 1602 in response to frame 1608. Frame 1610 may indicate acceptance by STA 1604 of the allocation of the portion of the TXOP to STA 1604. Frame 1610 may be a CTS frame, a modified CTS frame, ora control frame, for example.

[0160] In an embodiment, frame 1608 may comprise an indication of whether AP 1602 enables (or intends to operate according to) the PS mode for the allocated portion of the TXOP. In another embodiment, the indication (or another indication in frame 1608) further indicates whether AP 1602 enables the AP power saving operation described herein for the allocated portion of the TXOP. In an implementation, when the indication indicates that AP 1602 disables the PS mode for the allocated portion of the TXOP, STA 1604 may interpret the indication as indicating that AP 1602 intends tooperate according to another mode (another power save mode or an active mode) during the allocated portion of the TXOP. In such a case, the AP power saving operation is considered disabled by STA 1604.

[0161] Frame 1608 may comprise / indicate a TXS mode for the allocated portion of the TXOP. As described in FIGs. 4 and 5 above, the TXS mode may be set to 1 or 2. Frame 1608 may further comprise a first time period that indicates the portion of the TXOP allocated to STA 1604. In an example, the first time period may be set to a value of X us. In an implementation where frame 1608 is an MRTT frame, frame 1608 may include a TXOP Sharing mode subfield, an AID12 subfield, and an Allocation Duration subfield as illustrated in FIG. 3. The TXOP Sharing mode subfield indicates the TXS mode for the allocated portion of the TXOP. The AID12 subfield may be set to an AID of STA 1604 to indicate that the allocation is for STA 1604. The Allocation Duration subfield may indicate the first time period.

[0162] In an embodiment, AP 1602 may enable the PS mode (and the AP power saving operation described herein) for an allocated portion of a TXOP when the TXS mode for the allocated portion of the TXOP is set to 2. For example, in example 1600, AP 1602 may set the TXS mode to 2 in frame 1608 and may enable the PS mode (and the AP power saving operation) during the first time period corresponding to the portion of the TXOP allocated to STA 1604. AP 1602 may indicate that the PS mode (and the AP power saving operation) is enabled in frame 1608 (or in another frame). The TXS mode set to 2 in frame 1608 indicates that STA 1604 may transmit one or more non-TB PPDUs to AP 1602 or to a peer STA during the first time period. In an example, the peer STA may be a STA having a connection for P2P communication or direct communication with STA 1604. In example 1600, it is assumed that STA 1606 is a peer STA of STA 1604. The one or more non-TB PPDUs may comprise a data frame, a control frame, a management frame, or an action frame.

[0163] In an embodiment, STA 1604 may indicate, e.g., in frame 1610, whether STA 1604 operates or intends to operate in a first transmission mode during the portion of the TXOP allocated to STA 1604. In an implementation, the first transmission mode may correspond to a transmission mode in which STA 1604 prioritizes transmission to AP 1602 over transmission to a peer STA, e.g., STA 1606, during the portion of the TXOP allocated to STA 1604. In another implementation, the first transmission mode may correspond to a transmission mode in which STA 1604 transmits, during the portion of the TXOP allocated to STA 1604, first buffered frames for AP 1602, before transmitting second buffered frames for a peer STA, e.g., STA 1606. That is, STA 1604 may first exhaust transmission of the first buffered frames for AP 1602 before beginning to transmit the second buffered frames for the peer STA. In an embodiment, the first transmission mode may be included in a frame separate from frame 1610. For example, STA 1604 may transmit, to AP 1602, a frame comprising the first transmission mode between frame 1610 and non-TB PPDU 1612 (e.g., a SIFS after frame 1610 and a SIFS before non-TB PPDU 1612).

[0164] In an embodiment, AP 1602 may be configured to transition to the first power state / mode after transmitting frame 1608. In an implementation, AP 1602 may be configured to operate in the second power state / mode while transmitting frame 1608 and to transition to the first power state / mode after transmitting frame 1608. In an implementation (illustrated as Option 1 in FIG. 16), AP 1602 may transition from the second power state / mode to the first power state / mode after transmitting frame 1608 and before the start of the allocated portion of the TXOP. In an implementation, in response toframe 1610 indicating that STA 1604 operates in the first transmission mode during the allocated portion of the TXOP, AP 1602 transitions from the first power state / mode to the second power state / mode. AP 1602 may maintain operation in the first power state / mode or may transition from the first power state / mode to the second power state / mode, in response to frame 1610 indicating that STA 1604 does not operate according to the first transmission mode during the allocated portion of the TXOP.

[0165] In another embodiment, AP 1602 may be configured to maintain operation in the second power state / mode after transmitting frame 1608 and after the start of the allocated portion of the TXOP. In an implementation (illustrated as Option 2 in FIG. 16), AP 1602 may transition from the second power state / mode to the first power state / mode after transmitting frame 1608 and after the start of the allocated portion of the TXOP. In an implementation, based on frame 1610 indicating that STA 1604 operates according to the first transmission mode, AP 1602 maintains its operation in the second power state / mode. AP 1602 may transition from the second power state / mode to the first power state / mode in response to receiving from STA 1604 a frame that causes or triggers AP 1602 to transition from the second power state / mode to the first power state / mode. In an embodiment, the frame is a frame that indicates absence of buffered frames for AP 1602 at STA 1604. In an implementation, the frame comprises a data frame with a “more data” field set to zero, which indicates to AP 1602 that STA 1604 exhausted, with the data frame, transmission of its buffered frames for AP 1602. In another implementation, based on frame 1610 indicating that STA 1604 does not operate according to the first transmission mode, AP 1602 may maintain operation in the second power state / mode or may transition to the first power state / mode.

[0166] In example 1600, STA 1604 may indicate in frame 1610 that STA 1604 operates according to the first transmission mode. As such, AP 1602 may transition from the first power state / mode to the second power state / mode in response to frame 1610 (Option 1) or may maintain operating in the second power state / mode (Option 2). STA 1604 may use the first time period to transmit one or more non-TB PPDUs to AP 1602 before transmitting one or more non-TB PPDUs to STA 1604. For example, STA 1604 may transmit non-TB PPDUs 1612 and 1616 to AP 1602. Non-TB PPDUs 1612 and 1616 may be PPDUs of the first category or the second category as described above. AP 1602 may respond to non-TB PPDUs 1612 and 1616 by transmitting BA frames 1614 and 1618 respectively to STA 1604. In an embodiment, STA 1604 may be configured to set to zero a “more data” field of a last PPDU that STA 1604 intends to transmit to AP 1602. For example, STA 1604 may set to zero the “more data” field of non-TB PPDU 1616. This indicates to AP 1602 that STA 1604 exhausted with non-TB PPDU 1616 transmission of its buffered frames for AP 1602. As such, AP 1602 may transition to the first power state / mode after receiving non-TB PPDU 1616. In an implementation, AP 1602 may transition to the first power state / mode after transmitting BA frame 1618 in response to non-TB PPDU 1616.

[0167] STA 1604 may then transmit non-TB PPDUs 1620 and 1624 to STA 1606. STA 1606 may respond to non-TB PPDUs 1620 and 1624 by transmitting respectively BA frames 1622 and 1626 to STA 1604.

[0168] In an embodiment (not shown in FIG. 16), AP 1602 may receive from STA 1604 a first frame indicating whether STA 1604 supports the PS mode illustrated in FIG. 9 and / or FIG. 10. The first frame may be an association request frame, a probe request frame, or a control frame. In an implementation, STA 1604 supporting the PS mode comprises STA 1604being able to transmit, to AP 1602, PPDU 1620 before transmitting, to AP 1602, a further frame (e.g., non-TB PPDUs 1624 and 1628) within the portion of the TXOP allocated to STA 1604.

[0169] In an embodiment (not shown in FIG. 16), AP 1602 may transmit to STA 1604 a second frame indicating whether AP 1602 supports the PS mode illustrated in FIG. 9 and / or FIG. 10 and the AP power saving operation described herein. The second frame may be a beacon frame, an association response frame, a probe response frame, or a control frame. AP 1602 may transmit the second frame in response to the first frame from STA 1604. In an implementation, AP 1602 supporting the PS mode comprises AP 1602 being able to transition to the first power state / mode within the portion of the TXOP allocated to STA 1604.

[0170] FIG. 17 illustrates an example process 1700 according to an embodiment. Example process 1700 is provided for the purpose of illustration only and is not limiting of embodiments. Example process 1700 may be performed by an AP such as AP 1202, AP 1302, AP 1402, AP 1502, and AP 1602, for example. As shown in FIG. 17, example process 1700 includes steps 1702 and 1704. In an embodiment, the AP may allocate to a first STA a portion of a TXOP obtained by the AP. The AP may perform example process 700 during the portion of the TXOP allocated to the first STA.

[0171] Step 1702 includes transitioning, by the AP, from a first power state / mode to a second power state / mode of a first power save mode. The first power save mode may be a dynamic PS mode or an LPL mode. In an embodiment, the first power state / mode comprises an awake state / mode and the second power state / mode comprises a listening state / mode of the first power save mode. In an embodiment, step 1702 comprises transitioning from the first power state / mode to the second power state / mode before a start of the portion of the TXOP allocated by the AP to the first STA or within the portion of the TXOP.

[0172] Step 1704 includes transitioning, by the AP and within the portion of the TXOP, from the second power state / mode to the first power state / mode, in response to receiving, from the first STA and within the portion of the TXOP, a first frame causing / requesting / indicating / triggering that the AP transition from the second power state / mode to the first power state / mode.

[0173] In an embodiment, process 1700 may further comprise transmitting, by the AP to the first STA, a second frame in response to the first frame. The second frame may comprise an initial control response frame, a CTS frame, a modified CTS frame, an Ack frame, or a BA frame.

[0174] In an embodiment, process 1700 may further comprise transmitting, by the AP, a third frame allocating to the first STA the portion of the TXOP. In an embodiment, the third frame may indicate that the AP enables the first power save mode. The third frame may comprise an MRTT frame, a trigger frame, or a control frame. In an embodiment, the third frame may indicate that the first STA is allowed to transmit a PPDU to a peer STA during the portion of the TXOP. In an embodiment, the third frame may comprise an instruction / command / indication for the first STA to operate in a first transmission during the portion of the TXOP. In an implementation, according to the first transmission mode, the first STA may prioritize transmission to the AP over transmission to a second STA. In another implementation, according to the first transmission mode, the first STA may transmit, during the portion of the TXOP, first buffered frames for the AP before transmitting second buffered frames for a second STA.

[0175] In an embodiment, process 1700 may further comprise receiving, by the AP from the first STA, a fourth frame indicating acceptance of allocation of the portion of the TXOP to the first STA. The fourth frame may comprise a CTS frame, a modified CTS frame, or a control frame. In an embodiment, the fourth frame may comprise an indication that the first STA operates in a first transmission mode during the portion of the TXOP. In an implementation, according to the first transmission mode, the first STA may prioritize transmission to a second STA over transmission to the AP. In another implementation, according to the first transmission mode, the first STA may transmit, during the portion of the TXOP, first buffered frames for the second STA before transmitting second buffered frames for the AP.

[0176] In an embodiment, the first frame may comprise a data frame comprised in a PPDU of the first category (e.g., non-HT PPDU). The PPDU of the first category may be transmitted by the first STA using a modulation and coding scheme from a basic MCS set (e.g., MCS 0, MCS 1 , MCS 2, MOS 3). In an implementation, the PPDU of the first category may comprise a single spatial stream and / or has a bandwidth of 20 MHz.

[0177] In an embodiment, the first frame may comprise a “more data field” set to zero.

[0178] In an embodiment, the first frame may comprise an RTS frame, an MRTT frame, a BAR frame, ora BSRP trigger frame.

[0179] In an embodiment, process 1700 may further comprise receiving, by the AP from the first STA, a fifth frame indicating whether the first STA supports the first power save mode. The fifth frame may comprise a probe request frame or an association request frame. In an embodiment, the first STA supporting the first power save mode may comprise the first STA being able to transmit, to the AP, the first frame before transmitting, to the AP, a further frame within the portion of the TXOP.

[0180] In response to the fifth frame, the AP may transmit a sixth frame indicating whether the AP supports the first power save mode. The sixth frame may comprise a beacon frame, a probe response frame, or an association response frame. In an embodiment, the AP supporting the first power save mode may comprise the AP being able to transition to the second power state / mode within the portion of the TXOP.

[0181] In an embodiment, step 1702 comprises transitioning from the first power state / mode to the second power state / mode after transmitting the third frame. In an embodiment, step 1702 comprises transitioning from the first power state / mode to the second power state / mode right after receiving the fourth frame.

[0182] In an embodiment, the first frame may indicate whether the AP is to maintain the second power state / mode or transition to the first power state / mode. Step 1704 may accordingly comprise transitioning from the second power state / mode to the first power state / mode based on the first frame indicating that the AP is to transition to the first power state / mode. If the first frame indicates that the AP is to maintain the second power state / mode, process 1700 may comprise, instead of step 1704, maintaining, by the AP, the second power state / mode.

[0183] In another embodiment, the first power state / mode may comprise a listening state / mode and the second power state / mode may comprise an awake state / mode of the first power save mode.

[0184] FIG. 18 illustrates an example process 1800 according to an embodiment. Example process 1800 is provided for the purpose of illustration only and is not limiting of embodiments. Example process 1800 may be performed by a firstSTA such as STA 1204, STA 1304, STA 1404, STA 1504, and STA 1604, for example. As shown in FIG. 18, example process 1800 includes steps 1802 and 1804.

[0185] Step 1802 includes receiving, from an AP, a first frame allocating to the first STA a portion of a TXOP obtained by the AP.

[0186] In an embodiment, the first frame may indicate that the AP enables the first power save mode. The first frame may comprise an MRTT frame, a trigger frame, or a control frame. In an embodiment, the first frame may indicate that the first STA is allowed to transmit a PPDU to a peer STA during the portion of the TXOP. In an embodiment, the first frame may comprise an instruction / command / indication for the first STA to operate in a first transmission during the portion of the TXOP. In an implementation, according to the first transmission mode, the first STA may prioritize transmission to the AP over transmission to a second STA. In another implementation, according to the first transmission mode, the first STA may transmit, during the portion of the TXOP, first buffered frames for the AP before transmitting second buffered frames for a second STA.

[0187] Step 1804 includes transmitting, to the AP and within the portion of the TXOP, a second frame requesting / triggering / indicating that the AP transition from a first power state / mode to a second power state / mode of a first power save mode. The first power save mode may be a dynamic PS mode or an LPL mode. In an embodiment, the first power state / mode may comprise an awake state / mode and the second power state / mode comprises a listening state / mode of the first power save mode.

[0188] In an embodiment, process 1800 may further comprise receiving a third frame in response to the second frame. The third frame may comprise an initial control response frame, a CTS frame, a modified CTS frame, an Ack frame, or a BA frame.

[0189] In an embodiment, process 1800 may further comprise transmitting, to the AP, a fourth frame indicating acceptance of allocation of the portion of the TXOP to the first STA. The fourth frame may comprise a CTS frame, a modified CTS frame, or a control frame. In an embodiment, the fourth frame may comprise an indication that the first STA operates in a first transmission mode during the portion of the TXOP. In an implementation, according to the first transmission mode, the first STA may prioritize transmission to a second STA over transmission to the AP. In another implementation, according to the first transmission mode, the first STA may transmit, during the portion of the TXOP, first buffered frames for the second STA before transmitting second buffered frames for the AP.

[0190] In an embodiment, the second frame may comprise a data frame comprised in a PPDU of the first category (e.g., non-HT PPDU). The PPDU of the first category may be transmitted by the first STA using a modulation and coding scheme from a basic MCS set (e.g., MCS 0, MCS 1 , MCS 2, MCS 3). In an implementation, the PPDU of the first category comprises a single spatial stream and / or has a bandwidth of 20 MHz.

[0191] In an embodiment, the second frame may comprise a “more data field” set to zero.

[0192] In an embodiment, the second frame may comprise an RTS frame, an MRTT frame, a BAR frame, or a BSRP trigger frame.

[0193] In an embodiment, process 1800 may further comprise transmitting, to the AP, a fifth frame indicating whether the first STA supports the first power save mode. The fifth frame may comprise a probe request frame or an association request frame In an embodiment, the first STA supporting the first power save mode may comprise the first STA being able to transmit, to the AP, the first frame before transmitting, to the AP, a further frame within the portion of the TXOP.

[0194] In response to the fifth frame, the first STA may receive from the AP a sixth frame indicating whether the AP supports the first power save mode. The sixth frame may comprise a beacon frame, a probe response frame, or an association response frame. In an embodiment, the AP supporting the first power save mode may comprise the AP being able to transition to the second power state / mode within the portion of the TXOP.

[0195] In an embodiment, the second frame may indicate whether the AP is to maintain the second power state / mode or transition to the first power state / mode. The AP may transition from the second power state / mode to the first power state / mode based on the second frame indicating that the AP is to transition to the first power state / mode. If the first frame indicates that the AP is to maintain the second power state / mode, the AP may maintain the second power state / mode.

[0196] In another embodiment, the first power state / mode may comprise a listening state / mode and the second power state / mode may comprise an awake state / mode of the first power save mode.

[0197] FIG. 19 illustrates an example process 1900 according to an embodiment. Example process 1900 is provided for the purpose of illustration only and is not limiting of embodiments. Example process 1900 may be performed by an AP such asAP 1602, for example. As shown in FIG. 19, example process 1900 includes steps 1902, 1904, 1906, 1908, and 1910. Step 1908 maybe optional.

[0198] Step 1902 includes transmitting a first frame allocating to a first STA a portion of a TXOP obtained by the AP. The first frame may comprise an MRTT frame, a trigger frame, or a control frame.

[0199] Step 1904 includes, in response to the first frame, receiving, from the first STA, a second frame indicating that the first STA operates in a first transmission mode during the portion of the TXOP. In an implementation, according to the first transmission mode, the first STA may prioritize transmission to the AP over transmission to a second STA. In another implementation, according to the first transmission mode, the first STA may transmit, during the portion of the TXOP, first buffered frames for the AP before transmitting second buffered frames for a second STA. The second frame may comprise a CTS frame, a modified CTS frame, or a control frame.

[0200] Step 1906 includes receiving, from the first STA, a third frame indicating absence of buffered frames for the AP at the first STA. The third frame may comprise a data frame, a management frame, or a control frame. In an embodiment, the third frame may comprise a data frame having a "more data” field set to zero.

[0201] Step 1908 includes transmitting, by the AP to the first STA, a fourth frame in response to the third frame. The fourth frame may comprise an Ack frame or a BA frame.

[0202] Step 1910 includes transitioning, by the AP, from a first power state / mode to a second power state / mode of a power save mode. The power save mode may be a dynamic PS mode or an LPL mode. In an embodiment, the first powerstate / mode may comprise an awake state / mode and the second power state / mode comprises a listening state / mode of the power save mode. In an embodiment, step 1910 may be performed after transmitting the fourth frame in step 1908.

[0203] FIG. 20 illustrates an example process 2000 according to an embodiment. Example process 2000 is provided for the purpose of illustration only and is not limiting of embodiments. Example process 2000 may be performed by a first STA such as STA 1604, for example. As shown in FIG. 20, example process 2000 includes steps 2002, 2004, 2006, and 2008. Step 2008 may be optional.

[0204] Step 2002 includes receiving, from an AP, a first frame allocating to the first STA a portion of a TXOP obtained by the AP. The first frame may comprise an MRTT frame, a trigger frame, or a control frame.

[0205] Step 2004 includes, in response to the first frame, transmitting, to the AP, a second frame indicating that the first STA operates in a first transmission mode during the portion of the TXOP. In an implementation, according to the first transmission mode, the first STA may prioritize transmission to the AP over transmission to a second STA. In another implementation, according to the first transmission mode, the first STA may transmit, during the portion of the TXOP, first buffered frames for the AP before transmitting second buffered frames for a second STA. The second frame may comprise a CTS frame, a modified CTS frame, or a control frame.

[0206] Step 2006 transmitting, to the AP, a third frame indicating absence of buffered frames for the AP at the first STA. The third frame may comprise a data frame, a management frame, or a control frame. In an embodiment, the third frame may comprise a data frame having a “more data” field set to zero.

[0207] Step 2008 includes receiving, by the first STA from the AP, a fourth frame in response to the third frame. The fourth frame may comprise an Ack frame or a BA frame.

Claims

CLAIMSWhat is claimed is:

1. A method comprising: transmitting, by an access point (AP), a first frame allocating to a first station (STA) a portion of a transmission opportunity (TXOP) obtained by the AP; after transmitting the first frame and before or within the portion of the TXOP, transitioning, by the AP, from a first mode to a second mode of a power save mode; after transitioning from the first mode to the second mode, receiving, by the AP from the first STA, a second frame causing the AP to transition from the second mode to the first mode; and transitioning, by the AP, from the second mode to the first mode, in response to the second frame.

2. A method comprising: transitioning, by an access point (AP), from a first mode to a second mode of a first power save mode, wherein the AP transitions from the first mode to the second mode before a start of a portion, of a transmission opportunity (TXOP), allocated by the AP to a first station (STA) or within the portion of the TXOP; and transitioning, by the AP and within the portion of the TXOP, from the second mode to the first mode, in response to receiving, from the first STA and within the portion of the TXOP, a first frame causing the AP to transition from the second mode to the first mode.

3. The method of claim 2, further comprising transmitting, by the AP to the first STA, a second frame in response to the first frame.

4. The method of claim 3, wherein the second frame comprises an initial control response frame, a clear-to-send (CT S) frame, a modified CTS frame, an acknowledgement (Ack) frame, ora Blockack (BA) frame.

5. The method of any of claims 2-3, further comprising transmitting, by the AP, a third frame allocating to the first STA the portion of the TXOP.

6. The method of claim 5, wherein the third frame comprises an indication that the AP enables the first power save mode.

7. The method of any of claims 5-6, wherein the third frame comprises a multi-user (MU) request-to-send (RTS) trigger frame, a trigger frame, ora control frame.

8. The method of any of claims 5-7, wherein the third frame indicates that the first STA is allowed to transmit a physical protocol data unit (PPDU) to a peer STA during the portion of the TXOP.

9. The method of any of claims 5-8, further comprising receiving, by the AP from the first STA, a fourth frame indicating acceptance of allocation of the portion of the TXOP to the first STA.

10. The method of claim 9, wherein the fourth frame comprises a clear to send (CTS) frame, a modified CTS frame, or a control frame.

11. The method of any of claims 9-10, wherein the fourth frame comprises an indication that the first STA operates in a first transmission mode during the portion of the TXOP.

12. The method of claim 11 , wherein according to the first transmission mode, the first STA prioritizes transmission to a second STA over transmission to the AP.

13. The method of claim 12, wherein according to the first transmission mode, the first STA transmits, during the portion of the TXOP, first buffered frames for the second STA before transmitting second buffered frames for the AP.

14. The method of any of claims 5-10, wherein the third frame comprises an indication for the first STA to operate in a first transmission during the portion of the TXOP.

15. The method of claim 14, wherein according to the first transmission mode, the first STA prioritizes transmission to the AP over transmission to a second STA.

16. The method of claim 14, wherein according to the first transmission mode, the first STA transmits, during the portion of the TXOP, first buffered frames for the AP before transmitting second buffered frames for a second STA.

17. The method of claim 2, wherein the first frame comprises a data frame comprised in a non- H ig ht-Throug hput (HT) physical layer protocol data unit (PPDU).

18. The method of claim 17, wherein the non-HT PPDU is transmitted using a modulation and coding scheme from a basic MOS set. (e.g„ MCS 0, MOS 1, MOS 2, MOS 3).

19. The method of any of claims 17-18, wherein the non-HT PPDU comprises a single spatial stream.

20. The method of any of claims 17-19, wherein the non-HT PPDU has a bandwidth of 20 MHz.

21. The method of any of claims 2-20, wherein the first mode comprises a lower capability mode and the second mode comprises a higher capability mode.

22. The method of claim 2, wherein the first mode comprises a lower capability mode and the second mode comprises a higher capability mode.

23. The method of claim 2 or 22, wherein the first frame comprises a “more data field” set to zero.

24. The method of claim 2, wherein the first frame comprises a request to send (RTS) frame, a multi-user (MU)-RTS trigger frame, a blockack request (BAR) frame, or a buffer status request poll (BSRP) trigger frame.

25. The method of claim 2, further comprising: receiving, by the AP from the first STA, a fifth frame indicating whether the first STA supports the first power save mode; and in response to the fifth frame, transmitting, by the AP to the first STA, a sixth frame indicating whether the AP supports the first power save mode26. The method of claim 25, wherein the first STA supporting the first power save mode comprises the first STA being able to transmit, to the AP, the first frame before transmitting, to the AP, a further frame within the portion of the TXOP.

27. The method of claim 25, wherein the AP supporting the first power save mode comprises the AP being able to transition to the second mode within the portion of the TXOP.

28. The method of claim 25, wherein the fifth frame comprises a probe request frame or an association request frame.

29. The method of claim 25, wherein the sixth frame comprises a beacon frame, a probe response frame, or an association response frame.

30. The method of claim 5, further comprising transitioning from the first mode to the second mode after transmitting the third frame.

31. The method of any of claims 9-13, further comprising transitioning from the first mode to the second mode right after receiving the fourth frame.

32. The method of claim 2, further comprising: receiving, by the AP, the first frame indicating whether the AP maintains the second mode or transitions to the first mode; and based on the first frame indicating that the AP transitions to the first mode, transitioning, by the AP, from the second mode to the first mode33. The method of claim 32, further comprising maintaining, by the AP, the second mode based on the first frame indicating that the AP maintains the second mode.

34. A method comprising: receiving, by a first station (STA) from an access point (AP), a first frame allocating to the first STA a portion of a transmission opportunity (TXOP) obtained by the AP; transmitting, by the first STA to the AP, a second frame in response to the first frame, the second frame indicating a transmission mode used by the STA during the portion of the TXOP; and transmitting, by the first STA to the AP and within the portion of the TXOP, a third frame causing the AP to transition from a first mode to a second mode of a first power save mode, wherein the first mode and the second mode are based on the transmission mode.

35. A method comprising: receiving, by a first station (STA) from an access point (AP), a first frame allocating to the first STA a portion of a transmission opportunity (TXOP) obtained by the AP; and transmitting, by the first STA to the AP and within the portion of the TXOP, a second frame causing the AP to transition from a first mode to a second mode of a first power save mode.

36. The method of claim 35, wherein the first frame comprises an indication that the AP enables the first power save mode.

37. The method of any of claims 35-36, further comprising receiving, by the STA, a third frame in response to the second frame.

38. The method of claim 37, wherein the third frame comprises an initial control response frame, a clear-to-send (CTS) frame, a modified CTS frame, an acknowledgement (Ack) frame, blockack (BA) frame, ora control frame.

39. The method of any of claims 35-38, wherein the first frame comprises a multi-user (MU) request-to-send (RTS) trigger frame, a trigger frame, or a control frame.

40. The method of claim 35, wherein the first frame indicates that the first STA is allowed to transmit a physical protocol data unit (PPDU) to a peer STA during the TXOP.

41. The method of any of claims 35-40, further comprising transmitting, by the first STA to the AP in response to the first frame, a fourth frame indicating acceptance of allocation of the portion of the TXOP to the first STA.

42. The method of claim 41, wherein the fourth frame comprises a clear to send (CTS) frame, a modified CTS frame, or a control frame.

43. The method of any of claims 41-42, wherein the fourth frame comprises an indication that the first STA operates in a first transmission mode during the portion of the TXOP.

44. The method of claim 43, wherein according to the first transmission mode, the first STA prioritizes transmission to a second STA over transmission to the AP.

45. The method of claim 44, wherein according to the first transmission mode, the first STA transmits, during the portion of the TXOP, first buffered frames for the second STA before transmitting second buffered frames for the AP.

46. The method of any of claims 35-42, wherein the first frame comprises an indication for the first STA to operate in a first transmission during the portion of the TXOP.

47. The method of claim 46, wherein according to the first transmission mode, the first STA prioritizes transmission to the AP over transmission to a second STA.

48. The method of claim 46, wherein according to the first transmission mode, the first STA transmits, during the portion of the TXOP, first buffered frames for the AP before transmitting second buffered frames for a second STA.

49. The method of claim 35, wherein the second frame comprises a data frame comprised in a non-Hight-Throughput (HT) physical layer protocol data unit (PPDU).

50. The method of claim 49, wherein the non-HT PPDU is transmitted using a modulation and coding scheme from a basic MCS set.

51. The method of any of claims 49-50, wherein the non-HT PPDU comprises a single spatial stream.

52. The method of any of claims 49-51, wherein the non-HT PPDU has a bandwidth of 20 MHz.

53. The method of any of claims 35-49, wherein the first mode comprises a higher capability mode and the second mode comprises a lower capability mode.

54. The method of claim 35, wherein the first mode comprises a lower capability mode and the second mode comprises a higher capability mode.

55. The method of claim 35 or 54, wherein the second frame comprises a “more data field” set to zero.

56. The method of claim 35, wherein the second frame comprises a request to send (RTS) frame, a multi-user (MU)- RTS trigger frame, a blockack request (BAR) frame, a buffer status request poll (BSRP) trigger frame.

57. The method of claim 35, further comprising: transmitting, by the first STA to the AP, a fifth frame indicating whether the first STA supports the first power save mode; andin response to the fifth frame, receiving, by the first STA from the AP, a sixth frame indicating whether the AP supports the first power save mode.

58. The method of claim 57, wherein the first STA supporting the first power save mode comprises the first STA being able to transmit, to the AP, the first frame before transmitting, to the AP, a further frame within the portion of the TXOP.

59. The method of claim 57, wherein the AP supporting the first power save mode comprises the AP being able to transition to the second mode within the portion of the TXOP.

60. The method of claim 57, wherein the fifth frame comprises a probe request frame or an association request frame.

61. The method of claim 57, wherein the sixth frame comprises a beacon frame, a probe response frame, or an association response frame.

62. The method of claim 35, wherein the second frame indicates whether the AP maintains the second mode or transitions to the first mode63. A device comprising: one or more processors; and memory storing instructions that, when executed by the one or more processors of the device, cause the device to perform a method according to any of claims 1-62.

64. A non-transitory computer-readable medium comprising instructions that, when executed by one or more processors of a device, cause the device to perform a method according to any of claims 1-62.

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