Dynamic power save mode operation

Abstract

A first station (STA) transmits to a second STA a first frame requesting that the second STA transition from a first power state / mode to a second power state / mode of a first power save mode. The first STA transmits to the second STA a second frame after the first frame, where the first STA does not receive a response to the first frame from the second STA after transmitting the first frame and before transmitting the second frame.

Description

Dynamic Power Save Mode OperationCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 557,653, filed February 26, 2024, which is hereby incorporated by reference in its entirety.BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

[0005] FIG. 3 illustrates 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.

[0006] FIG. 4 illustrates a High Efficiency (HE) Single User (SU) PPDU, an HE Multi-User (MU) PPDU, and an HE Extended Range (ER) SU PPDU.

[0007] FIG. 5 illustrates an Extremely High Throughput (EHT) Multi-user (MU) PPDU.

[0008] FIG. 6 illustrates an example trigger frame.

[0009] FIG. 7 illustrates an example multi-user request to send (MU-RTS) trigger frame.

[0010] FIG. 8 illustrates an example common info field.

[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 illustrates an example that highlights a problem that may arise in association with the power save mode of FIG. 9.

[0014] FIG. 12 illustrates an example of a power save mode according to an embodiment.

[0015] FIG. 13 illustrates an example of an implementation of the power save mode illustrated in FIG. 12 according to an embodiment.

[0016] FIG. 14 illustrates an example of another power save mode according to an embodiment.

[0017] FIG. 15 illustrates an example process according to an embodiment.

[0018] FIG. 16 illustrates another example process according to an embodiment.DETAILED DESCRIPTION

[0019] 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 exemplaryembodiments. 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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 a hardware machine (such as C, C++, Fortran, Java, Basic, Matlab or the like) or a modeling / simulation program such as Simulink, Stateflow, GNU Octave, or LabVIEWMathScript. It may be possible to implement modules using physical hardware that incorporates discrete or programmable analog, digital and / or quantum hardware. Examples of programmable hardware comprise computers, microcontrollers, microprocessors, application-specific integrated circuits (ASICs); field programmable gate arrays (FPGAs); and complex programmable logic devices (CPLDs). Computers, microcontrollers, and microprocessors are programmed using languages such as assembly, C, C++ or the like. FPGAs, ASICs and CPLDs are often programmed using hardware description languages (HDL) such as VHSIC hardware description language (VHDL) or Verilog that configure connections between internal hardware modules with lesser functionality on a programmable device. The mentioned technologies are often used in combination to achieve the result of a functional module.

[0027] FIG. 1 illustrates example wireless communication networks in which embodiments of the present disclosure may be implemented.

[0028] 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.

[0029] 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.

[0030] 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 130and may have the same service set identification (SSID).

[0031] 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.

[0032] 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).

[0033] 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.

[0034] A STA as a predetermined functional medium may include a medium access control (MAC) layer that complies with an IEEE 802.11 standard. A physical layer interface for a radio medium may be used among the APs and the non- AP stations (STAs). The STA may also be referred to using various other terms, including mobile terminal, wireless device, wireless transmit / receive unit (WTRU), user equipment (UE), mobile station (MS), mobile subscriber unit, or user. For example, the term “user" 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.

[0035] 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 PLOP service data unit (PSDU). For example, the PSDU may include a PHY Convergence Protocol (PLCP) preamble and header and / or one or more MAC protocol data units (MPDUs). The information provided in the PHY preamble may be used by a receiving device to decode the subsequent data in the PSDU. In instances in which PPDUs are transmitted over a bonded channel (channel formed through channel bonding), the preamble fields may be duplicated and transmitted in each of the multiple component channels. The PHY preamble may include both alegacy 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.

[0036] 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 520 MHz by bonding together multiple 20 MHz channels.

[0037] FIG. 2 is a block diagram illustrating example implementations of a STA 210 and an AP 260. As shown in FIG. 2, STA 210 may include at least one processor 220, a memory 230, and at least one transceiver 240. AP 260 may include at least one processor 270, a memory 280, and at least one transceiver 290. Processor 220 / 270 may be operatively connected to memory 230 / 280 and / or to transceiver 240 / 290.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] FIG. 3 illustrates a non- High Throughput (non-HT) PPDU 310, a High Throughput (HT) mixed mode PPDU 320, and a Very High Throughput (VHT) PPDU 330.

[0042] Non-HT PPDU 310 may be used by STAs conforming to the IEEE 802.11a standard amendment. As shown in FIG. 3, non-HT PPDU 310 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 ps preamble of non-HT PPDU 310.

[0043] The L-STF may be used by a receiver of non-HT PPDU 310 to synchronize with the carrier frequency and frame timing of a transmitter of non-HT PPDU 310 and to adjust the receiver signal gain. The L-LTF may be used by the receiver of non-HT PPDU 310 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 310.

[0044] The L-SIG contains parameters needed to demodulate the Data field, which contains a payload of non-HT PPDU 310. The L-SIG may be equalized using the channel coefficients estimated using the L-LTF and demodulated to obtain the demodulation parameters of the Data field. The Data Field includes one or more symbols each having a duration of 4 ps, where 3.2 ps carry symbol information and 0.8 ps carry a Guard Interval (Gl).

[0045] For non-HT PPDUs, the only supported bandwidth is 20 MHz, which is divided into 64 subcarriers. As such, non- HT PPDU 310 may be encoded using a subcarrier spacing of 20MHz / 64 or 312.5kHz.

[0046] HT mixed mode PPDU 320 may be used by STAs conforming to the IEEE 802.11n standard amendment. HT mixed mode PPDU 320 can support MIMO to up to 4 spatial streams, which enhances spectral efficiency four folds. HT mixed mode PPDU 320 has a minimum preamble duration of 35.6 ps, which may increase depending on the number of spatial streams carried by the PPDU.

[0047] As shown in FIG. 3, HT mixed mode PPDU 320 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.

[0048] 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.

[0049] VHT PPDU 330 may be used by STAs conforming to the IEEE 802.11 ac standard amendment. VHT PPDU 330 can support MIMO transmission to up to 8 spatial streams, which enhances spectral efficiency eight folds. VHT PPDU 330 has a minimum preamble duration of 39.6 ps, which may increase depending on the number of spatial streams carried by VHT PPDU 330.

[0050] As shown in FIG. 3, VHT PPDU 330 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 330 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.

[0051] 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.

[0052] FIG. 4 illustrates a High Efficiency (HE) Single User (SU) PPDU 410, an HE Multi-User (MU) PPDU 420, and an HE Extended Range (ER) SU PPDU 430. HE SU PPDU 410, HE MU PPDU 420, and HE ER SU PPDU 430 maybe used by STAs conforming to the IEEE 802.11ax standard amendment.

[0053] HE SU PPDU 410 supports higher spectral efficiency compared to VHT PPDU 330 due to increased subcarrier spacing and higher order modulation support. HE SU PPDU 410 has a minimum preamble duration of 44 ps.

[0054] As shown in FIG. 4, HE SU PPDU 410 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.

[0055] Similar to HE SU PPDU 410, HE MU PPDU 420 supports higher spectral efficiency compared to VHT PPDU 330. HE MU PPDU 420 also supports OFDMA. Due to denser subcarrier spacing (as in HE SU PPDU 410), HE MU PPDU 420 allows for payloads of multiple users to be multiplexed in the frequency domain in the Data field. HE MU PPDU 420 supports multiplexing the payload of up to 9 users in a single 20 MHz band. HE MU PPDU 420 has a minimum preamble duration of 47.2 ps, which may increase depending on the number of spatial streams carried by HE MU PPDU 420.

[0056] As shown in FIG. 4, HE MU PPDU 420 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 410, HE MU PPDU 420 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 420.

[0057] For HE SU PPDU 410 and HE MU PPDU 420, 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.

[0058] For both HE SU PPDU 410 and HE MU PPDU 420, 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 410 and HE MU PPDU 420 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 410 or HE MU PPDU 420, 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.

[0059] As shown in FIG. 4, HE ER SU PPDU 430 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 410, HE ER SU PPDU 430 has an HE-SIG-A that is duplicated in the time domain (16 ps long instead of 8 ps long in HE SU PPDU 410). 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.

[0060] FIG. 5 illustrates an Extremely High Throughput (EHT) Multi-user (MU) PPDU 500. EHT MU PPDU 500 may be used by STAs conforming to the IEEE 802.11be standard amendment. EHT MU PPDU 500 supports OFDMA up to a bandwidth of 320MHz. EHT MU PPDU 530 can improve spectral efficiency due to support of a higher order modulation compared to other PPDUs (e.g., HE SU PPDU 410 and HE MU PPDU 420) while supporting the same number of spatial streams. EHT MU PPDU 500 has a minimum preamble duration of 47.2 ps, which may increase depending on the number of spatial streams carried by EHT MU PPDU 500.

[0061] As shown in FIG. 5, EHT MU PPDU 500 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 500 may be used by a transmitting STA for both SU and MU transmissions.

[0062] The U-SIG is intended to ensure forward compatibility of EHT MU PPDU 500. 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.

[0063] 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 530.

[0064] The Gl portion of the EHT-LTF and Data fields of EHT MU PPDU 500 may be one of: 0.8 s, 1 .6 ps, or 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.

[0065] 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 500 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 500, 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.

[0066] FIG. 6 illustrates an example trigger frame 600. Trigger frame 600 may correspond to a basic trigger frame as defined in the existing IEEE 802.11ax standard amendment. Trigger frame 600 may be used by an AP to allocate resources for and solicit one or more TB PPDU transmissions from one or more STAs. Trigger frame 600 may also carry other information required by a responding STA to transmit a TB PPDU to the AP.

[0067] As shown in FIG. 6, trigger frame 600 includes a Frame Control field, a Duration field, a receiver address (RA) field, a transmitter address (TA) field, a Common Info field, a User List Info field, a Padding field, and an FCS field.

[0068] The Frame Control field includes the following subfields: protocol version, type, subtype, To DS, From DS, more fragments, retry, power management, more data, protected frame, and +HTC.

[0069] The Duration field indicates various contents depending on frame type and subtype and the QoS capabilities of the sending STA. For example, in control frames of the power save poll (PS-Poll) subtype, the Duration field carries an association identifier (AID) of the STA that transmitted the frame in the 16 least significant bits (LSB), and the 2 most significant bits (MSB) are both set to 1. In other frames sent by STAs, the Duration field contains a duration value (in microseconds) which is used by a recipient to update a network allocation vector (NAV).

[0070] The RA field is the address of the STA that is intended to receive the incoming transmission from the transmitting station. The TA field is the address of the STA transmitting trigger frame 600 if trigger frame 600 is addressed to STAs that belong to a single BSS. The TA field is the transmitted BSSID if the trigger frame 600 is addressed to STAs from at least two different BSSs of the multiple BSSID set.

[0071] The common info field may have a format as illustrated by common info field 800 described further below. The common info field specifies a trigger frame type of trigger frame 600, a transmit power of trigger frame 600 in dBm, and several key parameters of a TB PPDU that is transmitted by a STA in response to trigger frame 600. The trigger frame type of a trigger frame used by an AP to receive QoS data using UL MU operation is referred to as a basic trigger frame.

[0072] The User List Info field contains a User Info field per STA addressed in trigger frame 600. The per STA User Info field includes, among others, an AID subfield, an RU Allocation subfield, a Spatial Stream (SS) Allocation subfield, an MCS subfield to be used by a STA in a TB PPDU transmitted in response to trigger frame 600, and a Trigger Dependent User Info subfield. The Trigger Dependent User Info subfield can be used by an AP to specify a preferred access category (AC) per STA. The preferred AC sets the minimum priority AC traffic that can be sent by a participating STA. The AP determines the list of participating STAs, along with the BW, MCS, RU allocation, SS allocation, Tx power, preferred AC, and maximum duration of the TB PPDU per participating STA.

[0073] The Padding field is optionally present in trigger frame 600 to extend the frame length to give recipient STAs enough time to prepare a response for transmission one SIFS (short interframe spacing) after the frame is received. The Padding field, if present, is at least two octets in length and is set to all 1s.

[0074] The FCS field is used by a STA to validate a received frame and to interpret certain fields from the MAC headers of a frame.

[0075] FIG. 7 illustrates an example multi-user request to send (MU-RTS) trigger frame 700. MU-RTS trigger frame 700 may be used by an AP to solicit simultaneous CTS frames from multiple STAs to transmit a downlink (DL) MU PPDU to the multiple STAs. As shown in FIG. 7, MU-RTS trigger frame 700 may comprise a frame control field, a duration field, an RA field, a TA field, a common info field, one or more user info fields, a padding field, and an FCS field. The frame control, TA, RA, padding, and FCS fields may be similar to the corresponding fields of trigger frame 600 described above. The common info field may have a format as illustrated by common info field 800 described further below. The durationfield may be set to the time, in microseconds, required to transmit the DL MU PPDU, plus the time required to transmit one CTS frame, one ACK frame (if required), and three SIPS periods.

[0076] The one or more user info fields correspond respectively to the one or more STAs solicited by MU-RTS trigger frame 700. As shown in FIG. 7, a user info field may comprise an AID12 subfield, an RU allocation subfield, reserved bits, and a PS 160 subfield. The AID12 subfield comprises an association identifier of the STA to which the user info field is addressed. The RU allocation subfield indicates a channel on which the solicited STA is to transmit the CTS frame. In an example, this may include a primary 20 MHz channel, a primary 40 MHz, a primary 80 MHz channel, a primary 160 MHz, an 80+80 Mhz channel, or a 320 MHz channel.

[0077] FIG. 8 illustrates an example Common Info field 800. Common Info field 800 may be an embodiment of the Common Info field of trigger frame 600 or MU-RTS trigger frame 700, for example. As shown in FIG. 8, Common Info field 800 may include a Trigger Type subfield, a UL Length subfield, a More TF subfield, a CS required subfield, a UL BW subfield, a Gl and HE / EHT-LTF Type / Triggered TXS Mode subfield, a first Reserved subfield, a Number of HE / EHT-LTF Symbols subfield, a second Reserved subfield, an LDPC Extra Symbol Segment subfield, an AP Tx Power subfield, a Pre-FEC Padding Factor subfield, a PE Disambiguity subfield, an UL Spatial Reuse subfield, a third Reserved subfield, an HE / EHT P180 subfield, a Special User Info Field Flag subfield, an EHT Reserved subfield, a fourth Reserved subfield, and a Trigger Dependent Common Info subfield. The Trigger Type subfield, UL Length subfield, More TF subfield, CS required subfield, UL BW subfield, Gl and HE-LTF Type / Triggered TXS Mode subfield, first Reserved subfield, Number of HE / EHT-LTF Symbols subfield, second Reserved subfield, LDPC Extra Symbol Segment subfield, AP Tx Power subfield, Pre-FEC Padding Factor subfield, PE Disambiguity subfield, UL Spatial Reuse subfield, third Reserved subfield, HE / EHT P180 subfield, Special User Info Field Flag subfield, EHT Reserved subfield, fourth Reserved subfield, and Trigger Dependent Common Info subfield may have the same content and interpretation as corresponding subfields of an EHT variant Common Info field defined in the IEEE 802.11 be draft amendment (“IEEE P802.11be / D3.1 , March 2023”).

[0078] 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.

[0079] 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.

[0080] 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 410, HE MU PPDU 420, or HE ER SU PPDU 430, an EHT PPDU such as EHT MU PPDU 500, 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.

[0081] 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.

[0082] 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 (ICF) 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.

[0083] 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 STA 904 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).

[0084] 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 powerstate / 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 before transmitting 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 (SIFS) after receiving ICF 906.

[0085] On receiving ICR 908, STA 902 initiates transmission of PPDU 910. In an implementation, STA 902 transmits PPDU 910 a SIFS 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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 anend 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.

[0090] 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.

[0091] 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 IGF 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.

[0092] 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.

[0093] 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 powerstate / 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.

[0094] FIG. 11 illustrates an example 1100 that highlights a problem that may arise in association with the power save mode illustrated in FIG. 9. As shown in FIG. 11, example 1100 also includes AP 1002 and STA 1004 described above with respect to FIG. 10. Particularly, example 1100 includes an aspect of example 1000 described above, namely STA 1004 transmitting IGF 1008 to AP 1002; AP 1002 responding to STA 1004 with ICR 1010 and transitioning from the first power state / mode to the second power; STA 1004 transmitting a PPDU 1012 of the second category to AP 1002; and AP 1002 responding to PPDU 1012 by transmitting to STA 1004 a BA frame 1014 before / after returning to the first power state / mode.

[0095] Subsequently, data requiring transmission to AP 1002 of a PPDU 1106 of the second category may arrive at STA 1004. To transmit PPDU 1106, STA 1004 transmits an IGF 1102 to AP 1002. ICF 1102 may be similar to IGF 1008 described above. AP 1002 responds to ICF 1102 by transmitting an ICR 1104 and transitions from the first power state / mode to the second power state / mode. ICR 1104 may be similar to ICR 1010. On receiving ICR 1104, STA 1004 transmits PPDU 1106 to AP 1002. AP 1002 responds to PPDU 1106 by transmitting to STA 1004 a BA frame 1108 before / after returning to the first power state / mode.

[0096] As shown in example 1100, in accordance with the PS mode of FIG. 9, AP 1002 transmits an ICR after each time that it receives an ICF from STA 1004. As mentioned above, the ICR allows AP 1002 to reserve the channel for the PPDU to be transmitted by STA 1004 to AP 1002. However, in some cases, channel reservation for the PPDU to be transmitted by STA 1004 to AP 1002 may not be necessary. For example, the PPDU may be of a short duration (e.g., less than 200 ps) and may not benefit from TXOP protection to avoid hidden node interference. Requiring AP 1002 to transmit an ICR each time that AP 1002 is to receive a PPDU of the second category may significantly reduce the power savings achieved by operating AP 1002 in the first power state / mode. For example, it has been shown in some test cases that the time normalized power for transmitting is about 5 times the time normalized power for receiving.

[0097] Embodiments of the present disclosure, as further described below, address the above-described problem. In an aspect, a first STA transmits to a second STA a first frame requesting that the second STA 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, for example. The first power state / mode may be a lower capability state / mode, a lower power receive state / mode, or a listen / listening state / mode, for example. The second power state / mode may be a higher capability state / mode, a higher power receive state / mode, or an awake state / mode, for example. While in the first power state / mode, the second STA may be capable of receiving PPDUs of a first category. While in the second power state / mode, the second STA may be capable of receiving PPDUs of the first category and PPDUs of a second category. After transmitting the first frame, and without waiting for a response to the first frame from the second STA, the first STA transmits to the second STA a second frame. The second frame may be carried in a PPDU of the second category. In an embodiment, the first STA does not receive a response to the first frame from the second STA after transmitting the first frame and before transmitting the second frame. As the second does not respond to the first frame, power savingsobtained from operating the second STA in the first power save mode may be increased. In another aspect, the first STA receives from the second STA during a first time period a third frame comprising a first indication that the second STA operates in the first power save mode during a second time period In an embodiment, the third frame further comprises a second indication enabling or disabling solicitation by the first STA, in the first frame, of a response to the first frame when the second STA operates in the first power save mode. This allows the second STA to control / reduce the amount of response transmissions while in the first power save mode. In another aspect, the first frame comprises a second indication of whether the first STA solicits a response to the first frame. In an embodiment, when the second indication indicates that the first STA does not solicit the response to the first frame, the first STA transmits the second frame a short interframe space (SIFS) after transmitting the first frame. The first STA may thus transmit the second frame without a risk of interference from another STA, despite the non-transmission by the second STA of a response to the first frame. In a further aspect, the first STA transmits the second frame a point coordination function interframe space (PIFS) after transmitting the first frame. This allows the second STA to transmit a response to the first frame, if desired, before the first STA transmits the second frame.

[0098] FIG. 12 illustrates an example 1200 of a power save mode according to an embodiment. As shown in FIG. 12, example 1200 includes STAs 1202 and 1204. STAs 1202 and 1204 may each be an AP STA or a non-AP STA. For example, STA 1202 may be an AP STA and STA 1204 may be a non-AP STA associated with STA 1202 or another AP STA. In another example, STA 1202 may be a non-AP STA and STA 1204 may be an AP STA with which STA 1202 is associated or another non-AP STA. It is assumed in example 1200 that STA 1202 implements the PS mode illustrated in FIG. 12.

[0099] In an implementation, a STA (AP STA or non-AP STA) implementing the PS mode illustrated in FIG. 12 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 / mode 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.

[0100] 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 410, HE MU PPDU 420, or HE ER SU PPDU 430, an EHT PPDU such as EHT MU PPDU 500, 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.

[0101] 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.

[0102] In an implementation, as illustrated in example 1200, 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. 12, STA 1202, 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 1204. Specifically, STA 1204 may transmit an ICF 1206 to STA 1202 requesting that STA 1202 transition from the first power state / mode to the second power state / mode of the PS mode. STA 1204 may request that STA 1202 transition from the first power state / mode to the second power state / mode in order to transmit to STA 1202 a PPDU 1208 of the second category that STA 1202 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).

[0103] ICF 1206 may be carried in a PPDU of the first category or the second category. In an embodiment, ICF 1206 may be a trigger frame as illustrated by trigger frame 600, an MU-RTS trigger frame as illustrated by MU-RTS trigger frame 700, an RTS frame, or a BAR frame.

[0104] In an embodiment, ICF 1206 comprises an indication of whether STA 1204 solicits a response to ICF 1206. In an implementation, where ICF 1206 is a trigger frame or an MU-RTS trigger frame, the indication may be provided in a common info field or in a user info field of the frame. For example, referring to FIG. 8, the indication may be provided in a reserved field (e.g., B22, B53, B56-B63) of the common info field of an MU-RTS trigger frame.

[0105] In example 1200, the indication comprised in ICF 1206 may indicate that STA 1204 does not solicit a response to ICF 1206 from STA 1202. As such, STA 1202 may not respond with an ICR to STA 1204 whether or not ICF 1206 is transmitted in a frame format that solicits a response without the indication (e.g. MU-RTS). In another example (not shown in FIG. 12), the indication of ICF 1206 may indicate that STA 1204 solicits a response to ICF 1206 from STA 1202 whether or not ICF 1206 is transmitted in a frame format that does not solicit a response without the indication. As such, STA 1202 may not respond with an ICR to STA 1204.

[0106] In an embodiment, where the indication of ICF 1206 indicates that STA 1204 does not solicit a response to ICF 1206 from STA 1202, STA 1204 may transmit PPDU 1208 without waiting for an ICR from STA 1202. In an embodiment, STA 1204 may transmit PPDU 1208 a SIFS after transmitting ICF 1206. The transmission by STA 1204 of PPDU 1208 only a SIFS after transmitting ICF 1206 ensures that STA 1204 remains the holder of the TXOP initiated by the transmission of ICF 1206. That is, with STA 1202 not transmitting an ICR in response to ICF 1206 and with STA 1204 transmitting PPDU 1208 a SIFS after ICF 1206, no other STA may gain access to the shared channel between ICF 1206 and PPDU 1208.

[0107] In another embodiment, STA 1204 may transmit ICF 1206 on a first frequency channel and may transmit PPDU 1208 on a second frequency channel. The first frequency channel and the second frequency channel may be different. For example, the first frequency channel may correspond to a primary 20 MHz channel, and the second frequency channel may correspond to a secondary 20 MHz, 40 MHz, 80 MHz or 160 MHz channel. In this example, the ICF 1206 may indicate an identifier of the secondary channel where PPDU 1208 is to be transmitted. In another example, the first frequency channel may correspond to a first link of STA 1204 while the second frequency channel may correspond to a second link of STA 1204. In this example, the ICF 1206 may indicate a link identifier of the second link where PPDU 1208 is to be transmitted.

[0108] On receiving ICF 1206, STA 1202 initiates a transition from the first power state / mode to the second power state / mode. For example, on receiving ICF 1206, STA 1202 may enable / poweron receiver capabilities needed to receive PPDU 1208 of the second category that STA 1204 wishes to transmit to STA 1202. 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 1202. In an embodiment, STA 1202 may transmit a frame indicating the state transition duration. For example, when STA 1202 is an AP STA, STA 1202 may indicate the state transition duration in a beacon frame, an association response frame, or a probe response frame, for example. In an embodiment, if the state transition duration is greater than a pre-determined duration, STA 1204 may be configured to insert padding bits into ICF 1206 to provide STA 1202 with additional time to transition from the first power state / mode to the second power state / mode before STA 1204 begins transmitting PPDU 1208. In an embodiment, the length of the padding bits may be determined based on the state transition duration associated with STA 1202. In an embodiment, STA 1204 may pad ICF 1206 based on the indication comprised in ICF 1206 indicating that STA 1204 does not solicit a response to ICF 1206 from STA 1202. In another embodiment, STA 1204 may pad ICF 1206 based on the indication comprised in ICF 1206 indicating that STA 1204 does not solicit a response to ICF 1206 from STA 1202 and further based on the state transition duration being greater than the duration of a SIFS.

[0109] After transitioning to the second power state / mode, STA 1202 may receive PPDU 1208 from STA 1204. In an embodiment, PPDU 1208 may comprise an indication of whether an acknowledgment of PPDU 1208 is requested from STA 1202. In example 1200, the indication comprised in PPDU 1208 may indicate that STA 1204 does not request an acknowledgment of PPDU 1208 from STA 1202. As such, STA 1202 may not transmit a BA frame in response to PPDU 1208 and may return to the first power state / mode after receiving PPDU 1208. As such, despite switching to the higher power second power state / mode, STA 1202 only receives during the second power state / mode, further decreasing power consumption at STA 1202. In another example (not shown in FIG. 12), the indication comprised in PPDU 1208 may indicate that STA 1204 requests an acknowledgment of PPDU 1208 from STA 1202. As such, STA 1202 may transmit a BA frame in response to PPDU 1208.

[0110] FIG. 13 illustrates an example 1300 of an implementation of the PS mode illustrated in FIG. 12 according to an embodiment. As shown in FIG. 13, example 1300 includes a STA 1302 and a STA 1304. STAs 1302 and 1304 may each be an AP STA or a non-AP STA. For example, STA 1302 may be an AP STA and STA 1304 may be a non-AP STAassociated with STA 1302 or another AP STA. In another example, STA 1302 may be a non-AP STA and STA 1304 may be an AP STA with which STA 1302 is associated or another non-AP STA. It is assumed in example 1300 that STA 1302 implements the PS mode illustrated in FIG. 12. Specifically, as described above, while in the first power state / mode of the PS mode, STA 1302 is capable of receiving PPDUs of a first category; and while in the second power state / mode of the PS mode, STA 1302 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. 12.

[0111] Additionally, STA 1302 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. 12. The other mode may have one or more power state / modes. STA 1302 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.

[0112] In an implementation, STA 1302 may be configured to announce a time period during which STA 1302 will operate in the PS mode. For example, as shown in FIG. 13, during a first time period, STA 1302 may transmit a frame 1306 indicating or announcing a second time period during which STA 1302 will operate in the PS mode. The second time period may or may not be adjacent to the first time period. In an implementation, STA 1302 may be operating in the other mode during the first time period. In another implementation, STA 1302 may be operating in the PS mode during the first time period. Frame 1306 may indicate a start time T 1 and an end time T2 of the second time period. Alternatively, frame 1306 may indicate a start time T1 and a duration of the second time period. In another implementation, frame 1306 may indicate a switch from the other mode to the PS mode during a second time period. For example, frame 1306 may indicate a time instant at which STA 1302 will switch from the other mode to the PS mode. In a further implementation, in addition to indicating a time period during which STA 1302 will operate in the PS mode or a time at which STA 1302 will switch to the PS mode, frame 1306 may further indicate a time period during which STA 1302 will operate in the first power state / mode or in the second power state / mode of the PS mode.

[0113] In an embodiment, STA 1302 may further transmit an indication of whether solicitation of a response to an ICF transmitted to STA 1302 while STA 1302 operates in the PS mode is enabled or disabled. The indication may be transmitted in frame 1306 or in another frame.

[0114] In an example, as shown in FIG. 13, STA 1302 may be in the other mode before switching to the PS mode at the beginning of the second time period. In an implementation, STA 1302 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. 13, STA 1302 be in the second power state / mode of the PS mode before the beginning of the second time period. STA 1302 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.

[0115] In an implementation, as illustrated in example 1300, STA 1302 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. 13, after switching to the PS mode at the beginning of the second time period, STA 1302 may operate in the first power state / mode.Subsequently, STA 1302 receives an ICF 1308 requesting that STA 1302 transition from the first power state / mode to the second power state / mode to receive from STA 1304 a PPDU 1310 of the second category.

[0116] In example 1300, STA 1302 may have disabled, e.g., in frame 1306, the solicitation of a response to an ICF transmitted to STA 1302 while STA 1302 operates in the PS mode during the second time period. In an implementation, based on an indication disabling ICF response solicitation, STA 1304 may not solicit in ICF 1308 a response to ICF 1308 from STA 1302. In another implementation, ICF 1308 may solicita response to ICF 1308 from STA 1302 notwithstanding an indication from STA 1302 disabling ICF response solicitation. In another implementation, STA 1302 may transmit ICF 1308 using a frame format by default (i.e. without the indication in frame 1306), may solicit a response from a target STA (e.g. MU-RTS). Based on the reception of frame 1306 disabling the solicitation of a response to an ICF transmitted to STA 1302, STA 1304 may be configured not to wait for a response after transmitting ICF 1308. In another example (not shown in FIG. 13), STA 1302 may have enabled, e.g., in frame 1306, ICF response solicitation during the second time period. In an implementation, based on an indication enabling ICF response solicitation, STA 1304 may or may not solicit in ICF 1308 a response to ICF 1308.

[0117] On receiving ICF 1308 from STA 1304, STA 1302 may initiate a transition from the first power state / mode to the second power state / mode. In an implementation, illustrated in example 1300, when STA 1302 disables ICF response solicitation during the second time period, STA 1302 does not transmit an ICR in response to ICF 1308. In an implementation, when STA 1302 disables ICF response solicitation during the second time period, STA 1302 does not transmit an ICR in response to ICF 1308 regardless of whether ICF 1308 solicits an ICR from STA 1302. In another implementation (not shown in FIG. 13), when STA 1302 enables ICF response solicitation during the second time period, STA 1302 transmits an ICR in response to ICF 1308 based on whether ICF 1308 solicits a response. In another implementation, when STA 1302 enables ICF response solicitation during the second time period, STA 1302 transmits an ICR in response to ICF 1308 regardless of whether ICF 1308 solicits a response.

[0118] In an implementation, STA 1302 may determine, from ICF 1308, a TXOP duration, a bandwidth, and / or a modulation and coding scheme (MCS) of PPDU 1310. STA 1302 may turn on / enable receiver capabilities based on the bandwidth and MCS indicated in ICF 1308.

[0119] After transmitting ICF 1308, STA 1304 initiates transmission of PPDU 1310. In an implementation, STA 1304 transmits PPDU 1310 a SIFS after transmitting ICF 1308. That is, STA 1304 does not wait for a response from STA 1302 before transmitting PPDU 1310. In an implementation, STA 1304 may use this approach when STA 1302 has disabled ICF response solicitation during the second time period or when STA 1302 has enabled ICF response solicitation during the second time period, STA 1302 does not solicit a response in ICF 1308, and STA 1302 is configured to transmit an ICR based on whether ICF 1308 solicits a response. In another implementation, STA 1304 transmits PPDU 1310 a SIFS from receiving a response to ICF 1308 from STA 1302. In an implementation, STA 1304 may use this approach when STA 1302 has enabled ICF response solicitation during the second time period and STA 1302 solicits a response in ICF 1308.

[0120] After receiving PPDU 1310, STA 1302 may transmit a BA frame 1312 to STA 1304. In an implementation, STA 1302 may return to the first power state / mode after receiving PPDU 1310. STA 1302 may transmit BA frame 1312 while in the second power state / mode or after returning to the first power state / mode. After the second time period, STA 1302 may transition to the other mode of operation or may remain in the first power state / mode of the PS mode.

[0121] FIG. 1 illustrates an example 1400 of another power save mode according to an embodiment. As shown in FIG. 14, example 1400 includes STAs 1402 and 1404. STAs 1402 and 1404 may each be anAP STAora non-AP STA. For example, STA 1402 may be an AP STA and STA 1404 may be a non-AP STA associated with STA 1402 or another AP STA. In another example, STA 1402 may be a non-AP STA and STA 1404 may be an AP STA with which STA 1402 is associated or another non-AP STA. It is assumed in example 1400 that STA 1402 implements the PS mode illustrated in FIG. 14.

[0122] In an implementation, a STA (AP STA or non-AP STA) implementing the PS mode illustrated in FIG. 14 maybe 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. The second power state / mode 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.

[0123] 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 410, HE MU PPDU 420, or HE ER SU PPDU 430, an EHT PPDU such as EHT MU PPDU 500, 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.

[0124] 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.

[0125] In an implementation, as illustrated in example 1400, 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. 14, STA 1402, which implements the PS mode, may operate in the first power state / mode and may transition to the second powerstate / mode in response to a solicitation from STA 1404. Specifically, STA 1404 may transmit an ICF 1406 to STA 1402 requesting that STA 1402 transition from the first power state / mode to the second power state / mode of the PS mode. STA 1404 may request that STA 1402 transition from the first power state / mode to the second power state / mode in order to transmit to STA 1402 a PPDU 1410 of the second category that STA 1402 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).

[0126] ICF 1406 maybe carried in a PPDU of the first category or the second category. In an embodiment, ICF 1406 may be a trigger frame as illustrated by trigger frame 600, an MU-RTS trigger frame as illustrated by MU-RTS trigger frame 700, an RTS frame, or a BAR frame.

[0127] In an embodiment, ICF 1406 comprises an indication of whether STA 1404 solicits a response to ICF 1406. In an implementation, where ICF 1406 is a trigger frame or an MU-RTS trigger frame, the indication may be provided in a common info field or in a user info field of the frame. For example, referring to FIG. 8, the indication may be provided in a reserved field (e.g., B22, B53, B56-B63) of the common info field of an MU-RTS trigger frame.

[0128] On receiving ICF 1406, STA 1402 initiates a transition from the first power state / mode to the second power state / mode. For example, on receiving ICF 1406, STA 1402 may enable / poweron receiver capabilities needed to receive PPDU 1410 of the second category that STA 1404 wishes to transmit to STA 1402.

[0129] In an embodiment, STA 1402 may have the option of whether or not to transmit a response to an ICF. That is, STA 1402 may determine whether or not to transmit a response to an ICF independent of whether the ICF includes an indication regarding ICF response solicitation or whether the ICF solicits a response. For instance, in example 1400, ICF 1406 may include an indication that STA 1404 solicits a response to ICF 1406. STA 1402 may consider the indication in ICF 1406 as a request or recommendation to transmit a response to ICF 1406. STA 1402, however, may or may not accept the request or recommendation and thus may or may not transmit a response to ICF 1406.

[0130] In an embodiment, as STA 1404 may not know whether STA 1402 will transmit a response to ICF 1406, STA 1404 may be configured to wait for a pre-determined duration after transmitting ICF 1406 before initiating transmission of PPDU 1410. In an implementation, when STA 1402 determines to transmit a response to an ICF such as ICF 1406, STA 1402 may be configured to transmit the response a SIFS after receiving the ICF. Accordingly, in an embodiment, STA 1404 may be configured to wait for at least a SIFS after transmitting ICF 1406 to determine whether STA 1402 has initiated transmission of a response to ICF 1406. In an implementation, when STA 1404 determines, a SIFS after transmitting ICF 1406, that STA 1402 has not initiated transmission of a response to ICF 1406, STA 1404 may initiate transmission of PPDU 1410 after a pre-determined number of slots. In an implementation, STA 1404 may initiate transmission of PPDU 1410 one slot time after determining that STA 1402 has not initiated transmission of a response to ICF 1406. That is, STA 1404 may initiate transmission of PPDU 1410 a PIFS after transmitting ICF 1406 based on determining, a SIFS after transmitting ICF 1406, that STA 1402 has not initiated transmission of a response to ICF 1406. In an implementation, STA 1404 may perform a clear channel assessment (CCA) a SIFS after transmitting ICF 1406. STA 1404 may transmit PPDU 1410 on condition that the CCA indicates that the channel is idle.

[0131] In an implementation, when STA 1404 determines, a SIFS after transmitting ICF 1406, that STA 1402 has initiated transmission of a response to ICF 1406, STA 1404 may initiate transmission of PPDU 1410 a SIFS after receiving the response to ICF 1406.

[0132] After transitioning to the second power state / mode, STA 1402 may receive PPDU 1410 from STA 1404. In an embodiment, PPDU 1410 may comprise an indication of whether an acknowledgment of PPDU 1410 is requested from STA 1402. In example 1400, the indication comprised in PPDU 1410 may indicate that STA 1404 requests an acknowledgment of PPDU 1410 from STA 1402. As such, STA 1402 may transmit a BA frame 1412 in response to PPDU 1410. In another example (not shown in FIG. 14), the indication comprised in PPDU 1410 may indicate that STA 1404 does not request an acknowledgment of PPDU 1410 from STA 1402. As such, STA 1402 may not transmit a BA frame in response to PPDU 1410 and may return to the first power state / mode after receiving PPDU 1410. As such, despite switching to the higher power second power state / mode, STA 1402 may only receive during the second power state / mode, further decreasing power consumption at STA 1402.

[0133] FIG. 15 illustrates an example process 1500 according to an embodiment. Example process 1500 is provided for the purpose of illustration only and is not limiting of embodiments. Example process 1500 may be performed by a first STA such as STA 1204, STA 1304, or STA 1404, for example. As shown in FIG. 15, process 1500 may include steps 1502 and 1504.

[0134] Step 1502 includes transmitting, by the first to a second STA, a first frame requesting that the second STA transition from a first power state / mode to a second power state / mode of a first power save mode. The second STA may be an AP STA or a non-AP STA. For example, the second STA may be a STA such as STA 1202, STA 1302, or STA 1402. In an embodiment, the first frame comprises a trigger frame, an MU-RTS trigger frame, an RTS frame, or a BAR frame.

[0135] In an embodiment, while in the first power state / mode, the second STA is capable of receiving PPDUs of a first category. While in the second power state / mode, the second STA is capable of receiving PPDUs of the first category and PPDUs of a second category. In an implementation, the second STA is not capable of receiving PPDUs of the second category during the first power state / mode. In an implementation, the second STA is capable of receiving PPDUs of only the first category during the first power state / mode.

[0136] 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 410, HE MU PPDU 420, or HE ER SU PPDU 430, an EHT PPDU such as EHT MU PPDU 500, 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.

[0137] The second 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 second STA, the first power state / mode may correspond to a default state / mode of the PS mode. As such, the second STA may operate in the first power state / mode and may transition to the second power state / mode as needed.

[0138] In an embodiment, the first frame is carried in a PPDU of the first category. In an embodiment, the first frame comprises a padding field. In an embodiment, process 1500 may further comprise receiving, by the first STA from the second STA, a frame indicating a duration associated with the second STA transitioning from the first power state / mode to the second power state / mode of the first power save mode. In an embodiment, the padding field may be based on the duration associated with the second STA transitioning from the first power state / mode to the second power state / mode of the first power save mode.

[0139] Step 1504 includes transmitting, by the first STA to the second STA, a second frame after the first frame. In an embodiment, the first STA does not wait for a response to the first frame from the second STA before transmitting the second frame. In an embodiment, the first STA does not receive a response to the first frame from the second STA after transmitting the first frame and before transmitting the second frame.

[0140] In an embodiment, process 1500 may further comprise receiving, by the first STA from the second STA and during a first time period, a third frame comprising a first indication that the second STA operates in the first power save mode during a second time period. In another embodiment, the third frame comprises a first indication of a switch of the second STA, during a second time period, from another mode of operation to the first power save mode. In an implementation, during the other mode of operation, the second STA is capable of receiving a physical layer protocol data unit (PPDU) of the second category in any power state / mode. In an embodiment, the third frame may be beacon frame, an association response frame, or a probe response frame.

[0141] In an embodiment, transmitting the second frame comprises transmitting the second frame during the second time period.

[0142] In an embodiment, the first frame comprises a second indication of whether the first STA solicits a response to the first frame. In an embodiment, where the second indication indicates that the first STA does not solicit the response to the first frame, step 1504 comprises transmitting the second frame a SIPS after transmitting the first frame. In an embodiment, where the first frame is a trigger frame, the second indication may be provided in a common info field or a user info field of the trigger frame.

[0143] In an embodiment, the third frame further comprises a second indication enabling or disabling solicitation by the first STA, in the first frame, of a response to the first frame when the second STA operates in the first power save mode. In an embodiment, where the second indication disables the solicitation by the first STA, in the first frame, of a response to the first frame when the second STA operates in the first power save mode, step 1504 comprises transmitting the second frame a SIPS after transmitting the first frame.

[0144] In another embodiment, step 1504 comprises transmitting the second frame a point coordination function interframe space (PIPS) after transmitting the first frame. In an embodiment, process 1500 may further compriseperforming, by the first STA, a CCA a SIFS after transmitting the first frame. Transmitting the second frame in step 1504 may be conditioned on the CCA indicating that a channel is idle.

[0145] In an embodiment, the second frame is carried in a PPDU of the second category.

[0146] In an embodiment, the first frame is transmitted via a first frequency channel and the second frame is transmitted via a second frequency channel.

[0147] FIG. 16 illustrates an example process 1600 according to an embodiment. Example process 1600 is provided for the purpose of illustration only and is not limiting of embodiments. Example process 1600 may be performed by a first STA such as STA 1202, STA 1302, or STA 1402, for example. As shown in FIG. 16, process 1600 may include steps 1602 and 1604.

[0148] Step 1602 includes receiving, by the first from a second STA, a first frame requesting that the first STA transition from a first power state / mode to a second power state / mode of a first power save mode. The second STA may be an AP STA or a non-AP STA. For example, the second STA may be a STA such as 1204, STA 1304, or STA 1404. In an embodiment, the first frame comprises a trigger frame, an MU-RTS trigger frame, an RTS frame, or a BAR frame.

[0149] In an embodiment, while in the first power state / mode, the first STA is capable of receiving PPDUs of a first category. While in the second power state / mode, the first STA is capable of receiving PPDUs of the first category and PPDUs of a second category. In an implementation, the first STA is not capable of receiving PPDUs of the second category during the first power state / mode. In an implementation, the first STA is capable of receiving PPDUs of only the first category during the first power state / mode.

[0150] 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 410, HE MU PPDU 420, or HE ER SU PPDU 430, an EHT PPDU such as EHT MU PPDU 500, 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.

[0151] The first 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 first STA, the first power state / mode may correspond to a default state / mode of the PS mode. As such, the first STA may operate in the first power state / mode and may transition to the second power state / mode as needed.

[0152] In an embodiment, the first frame comprises a padding field. In an embodiment, process 1600 may further comprise transmitting, by the first STA to the second STA, a frame indicating a duration associated with the first STA transitioning from the first power state / mode to the second power state / mode of the first power save mode. In anembodiment, the padding field may be based on the duration associated with the first STA transitioning from the first power state / mode to the second power state / mode of the first power save mode.

[0153] In an embodiment, the first frame is carried in a PPDU of the first category.

[0154] Step 1604 includes receiving, by the first STA from the second STA, a second frame after the first frame. In an embodiment, the first STA does not transmit a response to the first frame before receiving the second frame

[0155] In an embodiment, process 1600 may further comprise transmitting, by the first STA to the second STA and during a first time period, a third frame comprising a first indication that the first STA operates in the first power save mode during a second time period. In another embodiment, the third frame comprises a first indication of a switch of the first STA, during a second time period, from another mode of operation to the first power save mode. In an implementation, during the other mode of operation, the first STA is capable of receiving a physical layer protocol data unit (PPDU) of the second category in any power state / mode. In an embodiment, the third frame may be beacon frame, an association response frame, or a probe response frame.

[0156] In an embodiment, receiving the second frame comprises receiving the second frame during the second time period.

[0157] In an embodiment, the first frame comprises a second indication of whether the second STA solicits a response to the first frame. In an embodiment, where the second indication indicates that the second STA does not solicit the response to the first frame, step 1604 comprises receiving the second frame a SIPS after receiving the first frame. In an embodiment, where the first frame is a trigger frame, the second indication may be provided in a common info field or a user info field of the trigger frame.

[0158] In an embodiment, the third frame further comprises a second indication enabling or disabling solicitation by the second STA, in the first frame, of a response to the first frame when the first STA operates in the first power save mode. In an embodiment, where the second indication disables the solicitation by the second STA, in the first frame, of a response to the first frame when the first STA operates in the first power save mode, step 1604 comprises receiving the second frame a SIPS after receiving the first frame.

[0159] In another embodiment, step 1604 comprises receiving the second frame a PIFS after receiving the first frame.

[0160] In an embodiment, the second frame is carried in a PPDU of the second category.

[0161] In an embodiment, the first frame is transmitted via a first frequency channel and the second frame is transmitted via a second frequency channel.

Claims

CLAIMSWhat is claimed is:

1. A method comprising: receiving, by a first station (STA) from a second STA and during a first time period, a first frame comprising an indication that the second STA operates in a first power save mode during a second time period; based on the indication and during the second time period: transmitting, by the first STA to the second STA, a second frame requesting that the second STA transition from a first mode to a second mode of the first power save mode; and transmitting, by the first STA to the second STA, a third frame after the second frame, wherein the first STA does not receive a response to the second frame from the second STA after transmitting the second frame and before transmitting the third frame.

2. A method comprising: transmitting, by a first station (STA) to a second STA, a first frame requesting that the second STA transition from a first mode to a second mode of a first power save mode; and transmitting, by the first STA to the second STA, a second frame after the first frame, wherein the first STA does not receive a response to the first frame from the second STA after transmitting the first frame and before transmitting the second frame.

3. The method of claim 2, further comprising receiving, by the first STA from the second STA and during a first time period, a third frame comprising a first indication that the second STA operates in the first power save mode during a second time period.

4. The method of claim 2, further comprising receiving, by the first STA from the second STA and during a first time period, a third frame comprising a first indication of a switch of the second STA, during a second time period, from another mode of operation to the first power save mode.

5. The method of any of claims 3-4, wherein transmitting the second frame comprises transmitting the second frame during the second time period.

6. The method of any of claims 2-5, wherein the first frame comprises a second indication of whether the first STA solicits a response to the first frame.

7. The method of claim 6, wherein the second indication indicates that the first STA does not solicit the response to the first frame, and wherein transmitting the second frame comprises transmitting the second frame a short interframe space (SIFS) after transmitting the first frame.

8. The method of any of claims 2-7, wherein the first frame comprises a trigger frame.

9. The method of claim 8, wherein the trigger frame comprises a multi-user request to send (MU-RTS) frame.

10. The method of any of claims 8-9, wherein the trigger frame comprises a common info field or a user info field, and wherein the second indication is provided in the common info field or the user info field of the trigger frame.

11. The method of any of claims 3-5, wherein the third frame further comprises a second indication enabling or disabling solicitation by the first STA, in the first frame, of a response to the first frame when the second STA operates in the first power save mode.

12. The method of claim 11, wherein the second indication disables the solicitation by the first STA, in the first frame, of a response to the first frame when the second STA operates in the first power save mode, and wherein transmitting the second frame comprises transmitting the second frame a short interframe space (SIFS) after transmitting the first frame.

13. The method of any of claims 3-5, wherein transmitting the second frame comprises transmitting the second frame a point coordination function interframe space (PIFS) after transmitting the first frame.

14. The method of claim 13, further comprising performing, by the first STA, a clear channel assessment (CCA) a short interframe space (SIFS) after transmitting the first frame.

15. The method of claim 14, wherein transmitting the second frame is conditioned on the CCA indicating thata channel is idle.

16. The method of claim 2, wherein the first frame comprises a padding field.

17. The method of claim 2, further comprising receiving, by the first STA from the second STA, a third frame indicating a duration associated with the second STA transitioning from the first mode to the second mode of the first power save mode.

18. The method of any of claims 2-17, wherein, during the first mode, the second STA is capable of receiving physical layer protocol data units (PPDUs) of a first category.

19. The method of claim 18, wherein, during the second mode, the second STA is capable of receiving PPDUs of the first category and of a second category.

20. The method of claim 19, wherein, during the first mode, the second STA is not capable of receiving PPDUs of the second category.

21. The method of any of claims 18-20, wherein the first category comprises a PPDU having a non-high throughput (non-HT) format.

22. The method of any of claims 18-21, wherein the first category comprises a PPDU having a data rate that is less than or equal to 24 Mbps.

23. The method of any of claims 18-22, wherein the first category comprises a PPDU having a bandwidth of 20 MHz.

24. The method of any of claims 18-23, wherein the first category comprises a PPDU having a single spatial stream.

25. The method of any of claims 18-24, wherein the first frame is carried in a PPDU of the first category.

26. The method of any of claims 19-20, wherein the second category comprises a PPDU having: a high throughput (HT) format; a very high throughput (VHT) format; a high efficiency (HE) format; an extremely high throughput (EHT) format;an ultra-high reliability (UHR) format; or a physical layer version identifier field.

27. The method of any of claims 19-20 and 26, wherein the second category comprises a PPDU having a data rate that is greater than 24 Mbps.

28. The method of any of claims 19-20, 26, and 27, wherein the second category comprises a PPDU having a bandwidth greater than 20 MHz.

29. The method of any of claims 19-20 and 26-28, wherein the second category comprises a PPDU having a plurality of spatial streams.

30. The method of any of claims 19-20 and 26-29, wherein the second frame is carried in a PPDU of the second category.

31. The method of any of claims 19, 20, and 26-30, wherein, during the other mode of operation, the second STA is capable of receiving a physical layer protocol data unit (PPDU) of the second category in any mode.

32. The method of any of claims 2-31 , wherein the first frame is transmitted via a first frequency channel and the second frame is transmitted via a second frequency channel.

33. A method comprising: transmitting, by a first station (STA) to a second STA and during a first time period, a first frame comprising an indication that the first STA operates in a first power save mode during a second time period; based on the indication and during the second time period: receiving, by the first STA from the second STA, a second frame requesting that the first STA transition from a first mode to a second mode of the first power save mode; and receiving, by the first STA from the second STA, a third frame after the second frame, wherein the first STA does not transmit a response to the second frame to the second STA after receiving the second frame and before receiving the third frame.

34. A method comprising: receiving, by a first station (STA) from a second STA, a first frame requesting that the first STA transition from a first mode to a second mode of a first power save mode; and receiving, by the first STA from the second STA, a second frame after the first frame, wherein the first STA does not transmit a response to the first frame to the second STA after receiving the first frame and before receiving the second frame.

35. The method of claim 34, further comprising transmitting, by the first STA to the second STA and during a first time period, a third frame comprising a first indication that the first STA operates in the first power save mode during a second time period.

36. The method of claim 34, further comprising transmitting, by the first STA to the second STA and during a first time period, a third frame comprising a first indication of a switch of the first STA, during a second time period, from another mode of the operation to the first power save mode.

37. The method of any of claims 35-36, wherein receiving the second frame comprises receiving the second frame during the second time period.

38. The method of any of claims 34-37, wherein the first frame comprises a second indication of whether the second STA solicits a response to the first frame.

39. The method of claim 38, wherein the second indication indicates that the second STA does not solicit the response to the first frame, and wherein receiving the second frame comprises receiving the second frame a short interframe space (SIFS) after receiving the first frame.

40. The method of any of claims 34-39, wherein the first frame comprises a trigger frame.

41. The method of claim 40, wherein the trigger frame comprises a multi-user request to send (MU-RTS) frame.

42. The method of any of claims 40-41, wherein the trigger frame comprises a common info field or a user info field, and wherein the second indication is provided in the common info field or the user info field of the trigger frame.

43. The method of any of claims 35-37, wherein the third frame further comprises a second indication enabling or disabling solicitation by the second STA, in the first frame, of a response to the first frame when the first STA operates in the first power save mode.

44. The method of claim 43, wherein the second indication disables the solicitation by the second STA, in the first frame, of a response to the first frame when the first STA operates in the first power save mode, and wherein receiving the second frame comprises receiving the second frame a short interframe space (SIFS) after receiving the first frame.

45. The method of any of claims 35-37, wherein receiving the second frame comprises receiving the second frame a point coordination function interframe space (PIFS) after receiving the first frame.

46. The method of claim 34, wherein the first frame comprises a padding field.

47. The method of claim 34, further comprising transmitting, by the first STA to the second STA, a third frame indicating a duration associated with the first STA transitioning from the first mode to the second mode of the first power save mode.

48. The method of any of claims 34-47, wherein, during the first mode, the first STA is capable of receiving physical layer protocol data units (PPDUs) of a first category.

49. The method of claim 48, wherein, during the second mode, the first STA is capable of receiving PPDUs of the first category and of a second category.

50. The method of claim 49, wherein, during the first mode, the first STA is not capable of receiving PPDUs of the second category.

51. The method of any of claims 48-50, wherein the first category comprises a PPDU having a non-high throughput (non-HT) format.

52. The method of any of claims 48-51 , wherein the first category comprises a PPDU having a data rate that is less than or equal to 24 Mbps.

53. The method of any of claims 48-52, wherein the first category comprises a PPDU having a bandwidth of 20 MHz.

54. The method of any of claims 48-53, wherein the first category comprises a PPDU having a single spatial stream.

55. The method of any of claims 48-54, wherein the second frame is carried in a PPDU of the first category.

56. The method of any of claims 49-50, wherein the second category comprises a PPDU having: a high throughput (HT) format; a very high throughput (VHT) format; a high efficiency (HE) format; an extremely high throughput (EHT) format; an ultra-high reliability (UHR) format; or a physical layer version identifier field.

57. The method of any of claims 49-50 and 56, wherein the second category comprises a PPDU having a data rate that is greater than 24 Mbps.

58. The method of any of claims 49-50, 56, and 57, wherein the second category comprises a PPDU having a bandwidth greater than 20 MHz.

59. The method of any of claims 49-50 and 56-58, wherein the second category comprises a PPDU having a plurality of spatial streams.

60. The method of any of claims 49-50 and 56-59, wherein the first frame is carried in a PPDU of the second category.

61. The method of any of claims 49, 50, and 56-60, wherein, during the other mode of operation, the first STA is capable of receiving a physical layer protocol data unit (PPDU) of the second category in any mode.

62. The method of any of claims 34-57, wherein the first frame is received via a first frequency channel and the second frame is transmitted via a second frequency channel.

63. 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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