Enhanced power management technique for multi-link operation

Abstract

To provide a method, a system, and an apparatus that provide improvements through a power management technique for a non-AP multilink device (MLD) that is not operating as an access point (AP) capable of multilink operation (MLO).SOLUTION: A method includes establishing wireless links with an AP MLD including a first AP and a second AP, receiving signaling from the AP MLD including first timing information, determining second timing information on the basis of the first timing information, transmitting a frame including a link identifier (ID) associated with at least one of the wireless links, a power management (PM) mode indicator, and the second timing information, and receiving an acknowledgement (ACK) frame. After receiving the ACK frame, one or more non-AP stations in the non-AP MLD transition to a power save mode at a time associated with the second timing information on the basis of the link ID and the PM mode indicator.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] This application relates to wireless communications, including enhanced techniques for power management in multi-link operation between wireless stations and / or access points in a wireless networking system. [Background technology]

[0002] The use of wireless communication systems is rapidly increasing. Furthermore, wireless communication technology has evolved from voice-only communications to also include the transmission of data, such as Internet and multimedia content. A common short-range / medium-range wireless communication standard is the wireless local area network (WLAN). Modern WLANs are based on the IEEE 802.11 standard (and / or 802.11 for short) and are marketed under the brand name Wi-Fi®. A WLAN network links one or more devices to wireless access points, which in turn provide wider area Internet connectivity.

[0003] In an 802.11 system, devices that connect wirelessly to each other are referred to as "stations," "mobile stations," "user devices," "user equipment," or STAs or UEs for short. A wireless station can be either a wireless access point or a wireless client (and / or mobile station). An access point (AP), also called a wireless router, functions as a base station in a wireless network. An AP transmits and receives radio frequency signals to communicate with wireless client devices. An AP can also couple to the Internet in a wired and / or wireless manner. A wireless client operating on an 802.11 network can be any of a variety of devices, such as a laptop, tablet device, smartphone, smartwatch, or fixed device such as a desktop computer. A wireless client device is referred to herein as user equipment (and / or UE for short). Some wireless client devices are also referred to herein collectively as mobile devices or mobile stations (although, as noted above, wireless client devices may also be fixed devices as a whole).

[0004] Mobile electronic devices may take the form of smartphones or tablets that are typically carried by a user. Wearable devices (also called accessory devices) are a newer form of mobile electronic device, one example being the smartwatch. In addition, low-cost, low-complexity wireless devices intended for stationary or mobile deployment are also proliferating as part of the deployment of the "Internet of Things." In other words, there is an increasingly wide range of desired device complexities, capabilities, traffic patterns, and other characteristics.

[0005] Some WLANs may utilize multi-link operation (MLO), e.g., by simultaneously using multiple channels (e.g., links). MLO-enabled APs and / or STAs may be referred to as multi-link devices (MLDs). For example, an MLO-enabled AP may be referred to as an AP-MLD, and an MLO-enabled STA that is not operating as an AP may be referred to as a non-AP MLD. Thus, improvements in this area are desirable. Summary of the Invention

[0006] SUMMARY OF THE INVENTION The embodiments described herein relate to methods, systems, and apparatus for enhanced power management techniques in multi-link operation between wireless stations and / or access points in a wireless networking system.

[0007] In some embodiments, a method may include establishing at least two wireless links with an access point (AP) multilink device (MLD) comprising at least a first AP and a second AP, and receiving signaling from the AP MLD, the signaling including first timing information. The method may include determining second timing information based on the first timing information, and transmitting a frame including a link identifier (ID) associated with at least one of the at least two wireless links, a power management (PM) mode indicator, and the second timing information. Further, the method may include receiving an acknowledgement (ACK) frame, where after receiving the ACK frame, based on the link ID and the PM mode indicator, one or more non-AP stations (STAs) in the non-AP MLD transition to a power save (PS) mode at a time associated with the second timing information.

[0008] According to some embodiments, the second timing information may include a timing synchronization function (TSF). Further, according to some embodiments, the first timing information may include crosslink information exchange timing between any two APs in an AP MLD. According to some embodiments, the crosslink information exchange timing may be received during one of an association procedure, a beacon procedure, or an enhanced multilink (EML) operational mode notification (OMN) request and response mechanism. In some embodiments, the signaling may include information indicating which of the at least two radio links supports crosslink signaling. Also, the second timing information may include an absolute timing synchronization function (TSF) or a timing offset between the time the frame is transmitted and the time one or more non-AP STAs transition to PS mode. According to further embodiments, the frame may further include duration information associated with the duration of time one or more non-AP STAs are in PS mode. Furthermore, the frame may be a power management indication (PMI) frame.

[0009] In some embodiments, an apparatus may include a processor configured, when executing instructions stored in a memory, to cause a non-access point (non-AP) multilink device (MLD) comprising one or more non-access point (non-AP) stations (STAs) to perform operations including establishing at least two wireless links with an access point (AP) MLD comprising at least a first AP and a second AP. The operations may further include receiving signaling from the AP MLD including first timing information and determining second timing information based at least in part on the first timing information. The operations may further include transmitting a frame to the AP MLD including at least one link identifier (ID) associated with at least one of the at least two wireless links, a power management (PM) mode indicator, at least a portion of the second timing information, and duration information. The operations may further include, according to some embodiments, receiving an acknowledgement (ACK) frame from the first AP MLD, and after receiving the ACK frame, based at least in part on the at least one link ID and the PM mode indicator, one or more non-AP STAs of the non-AP MLD transition from a power save (PS) mode to an active mode at a time associated with the second timing information.

[0010] According to some embodiments, the PM mode indicator may be a bit value equal to 0 to indicate a transition of one or more non-AP STAs to an active mode. Additionally or alternatively, the frame may be transmitted using A-control field signaling. In some embodiments, the A-control field signaling may include at least one of an 8-bit Link ID subfield, a 1-bit PM Mode subfield, an 8-bit Timing Offset subfield, an 8-bit Duration subfield, or a 1-bit Reserved subfield. According to some embodiments, the A-control field signaling may be included in a Medium Access Control Protocol Data Unit (MPDU), a Control Response (CR) frame, or a Quality of Service Null (QN) frame.

[0011] According to another embodiment, a method may include establishing at least two wireless links with a non-AP multilink device (MLD) comprising at least two non-access point (non-AP) stations (STAs). The method may further include transmitting signaling comprising first timing information to the non-AP MLD and receiving a frame from the non-AP MLD including at least one link identifier (ID) associated with at least one of the at least two wireless links, a power management (PM) mode indicator, and second timing information. Further, the method may include transmitting an acknowledgement (ACK) frame to the non-AP MLD and determining, based at least in part on the at least one link ID and the PM mode indicator, that one or more non-AP STAs of the non-AP MLD transition to a power save (PS) mode at a time associated with the second timing information.

[0012] In some embodiments, the method may include providing at least one link ID and a PM mode indicator to one or more of the at least two wireless links via crosslink signaling. Further, the method may include refraining from communicating with one or more non-AP STAs while the one or more non-AP STAs are in the PS mode. According to some embodiments, the at least two wireless links may be simultaneous transmit / receive (STR) links. In other embodiments, one or more of the at least two wireless links may be enhanced multi-link single-radio (EMLSR) links or single-link enhanced multi-link single-radio (SL-EMLSR) links. Furthermore, the first timing information may include crosslink information exchange timing between at least any two APs of the AP. Furthermore, according to some embodiments, the crosslink information exchange timing may be received during one of an association procedure, a beacon procedure, or an enhanced multi-link (EML) operational mode notification (OMN) request and response mechanism.

[0013] This Summary is intended to provide a brief overview of some of the subject matter described in this document. Accordingly, it should be understood that the above features are merely examples and should not be construed as narrowing the scope or spirit of the subject matter described herein. Other features, aspects, and advantages of the subject matter described herein will become apparent from the following Detailed Description, the drawings, and the claims.

[0014] The present subject matter can be better understood when the following detailed description of the embodiments is considered in conjunction with the following drawings. [Brief explanation of the drawings]

[0015] [Figure 1] 1 illustrates an exemplary wireless communication system according to some embodiments.

[0016] [Figure 2] 1 illustrates an exemplary simplified block diagram of a wireless device according to some embodiments.

[0017] [Figure 3] 1 illustrates an exemplary WLAN communication system according to some embodiments.

[0018] [Figure 4] 1 shows an exemplary simplified block diagram of a WLAN access point (AP), according to some embodiments.

[0019] [Figure 5] 1 illustrates an exemplary simplified block diagram of a wireless station (STA), according to some embodiments.

[0020] [Figure 6] FIG. 1 illustrates an exemplary simplified block diagram of a wireless node according to some embodiments.

[0021] [Figure 7] 1 illustrates an example of an MLD, according to some embodiments. [Figure 8] 1 illustrates an example of an MLD, according to some embodiments.

[0022] [Figure 9A] 1 illustrates an exemplary aspect of a legacy method for power management (PM) of an MLD, according to some embodiments. [Figure 9B] 1 illustrates an exemplary aspect of a legacy method for power management (PM) of an MLD, according to some embodiments. [Figure 9C] 1 illustrates an exemplary aspect of a legacy method for power management (PM) of an MLD, according to some embodiments.

[0023] [Figure 10] FIG. 1 is a communication flow diagram illustrating an example enhanced method of power management techniques for non-AP MLD, according to some embodiments.

[0024] [Figure 11] FIG. 1 is a communication flow diagram illustrating an example enhanced method of power management techniques for AP MLD, according to some embodiments.

[0025] [Figure 12] 1 illustrates an example format for enhanced scheduled multilink PM mode indication signaling according to some embodiments.

[0026] [Figure 13A] FIG. 1 illustrates an enhanced method for MLD PM mode changes for simultaneous transmit / receive (STR) and enhanced multi-link single radio (EMLSR) link scenarios, according to some embodiments. [Figure 13B] FIG. 1 illustrates an enhanced method for MLD PM mode changes for simultaneous transmit / receive (STR) and enhanced multi-link single radio (EMLSR) link scenarios, according to some embodiments. [Figure 13C]FIG. 1 illustrates an enhanced method for MLD PM mode changes for simultaneous transmit / receive (STR) and enhanced multi-link single radio (EMLSR) link scenarios, according to some embodiments.

[0027] [Figure 14A] 1 illustrates signaling options and aspects for an enhanced method of PM for MLD, according to some embodiments. [Figure 14B] 1 illustrates signaling options and aspects for an enhanced method of PM for MLD, according to some embodiments. [Figure 14C] 1 illustrates signaling options and aspects for an enhanced method of PM for MLD, according to some embodiments. [Figure 14D] 1 illustrates signaling options and aspects for an enhanced method of PM for MLD, according to some embodiments.

[0028] [Figure 15] 1 illustrates an example scenario involving PM between an AP MLD and a non-AP MLD, where the AP MLD has a "leaky" AP problem, according to some embodiments.

[0029] While the features described herein are susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the drawings and detailed description are not intended to limit the invention to the particular forms disclosed, but rather to cover all modifications, equivalents, and alternatives within the spirit and scope of the present subject matter as defined by the appended claims. DETAILED DESCRIPTION OF THE INVENTION

[0030] acronym

[0031] Various abbreviations are used throughout this application. Provided below are definitions of the most prominently used acronyms that may appear throughout this application. UE: User Equipment AP: Access Point STA: Radio station TX: Send / Transmit RX: Receive / Receive DL: Downlink UL: Uplink ML: Multi-link MLD: Multi-Link Device LAN: Local Area Network WLAN:Wireless LAN RAT: Radio Access Technology ACK: Acknowledgement OTA: over-the-air SU: Single User MU: Multi-User MAC: Medium Access Control CPE: Extended Client Privacy BSS: Basic Service Set OBSS: Overlapping Basic Service Set SN: Sequence number PN: Packet number TID: Transaction Identifier AID: Association Identifier SSID: Service Set Identifier SAP: Service Access Point EDCA: Enhanced Distributed Channel Access TXOP: Transmission Opportunity P2P: Peer-to-Peer PM: Power management PMI: Power Management Indication PS: Power saving QoS: Quality of Service QN: QoS Null ID: Identifier EML: Extended Multi-Link OMN: Operation Mode Notification STR: Simultaneous transmission and reception EMLSR: Enhanced Multi-Link Single Radio TSF: Timing Synchronization Function L1: Link 1 L2: Link 2 L3: Link 3 MAC: Medium Access Control MPDU: MAC Protocol Data Unit CR: Control Response Terminology

[0032] The following is a description of terms used in this disclosure:

[0033] Memory medium—any of various types of non-transitory memory or storage devices. The term “storage medium” is intended to include, for example, installation media such as CD-ROMs, floppy disks, or tape drives; computer system memory or random access memory such as DRAM, DDR RAM, SRAM, EDO RAM, Rambus RAM; non-volatile memory such as magnetic media like flash, hard drives, or optical storage; registers, or other similar types of memory elements. A storage medium may also include other types of non-transitory memory, or combinations thereof. Additionally, a storage medium may be located in a first computer system on which a program is executed, or in a second, different computer system connected to the first computer system via a network such as the Internet. In the latter case, the second computer system can provide program instructions to the first computer for execution. The term “storage medium” may include two or more storage media that can reside in different locations, for example, in different computer systems connected via a network. A storage medium may store program instructions (e.g., embodied as a computer program) that can be executed by one or more processors.

[0034] Carrier Medium - memory media as described above, as well as physical transmission media such as buses, networks, and / or other physical transmission media that carry signals, such as electrical, electromagnetic, or digital signals.

[0035] Computer System—Any of various types of computing or processing systems, including a personal computer system (PC), mainframe computer system, workstation, network appliance, Internet appliance, personal digital assistant (PDA), television system, grid computing system, or other device or combination of devices. In general, the term “computer system” can be broadly defined to encompass any device (and / or combination of devices) having at least one processor that executes instructions from a storage medium.

[0036] Mobile device (and / or mobile station)—any of various types of computer system devices that are mobile or portable and perform wireless communication using WLAN communications. Examples of mobile devices include mobile phones or smartphones (e.g., iPhone™, Android™-based phones), and tablet computers such as iPad™ and Samsung Galaxy™. Various other types of devices fall into this category if they include Wi-Fi or both cellular and Wi-Fi communication capabilities, such as laptop computers (e.g., MacBook™), portable gaming devices (e.g., Nintendo DS™, PlayStation Portable™, Gameboy Advance™, iPhone™), portable Internet devices, and other handheld devices, as well as wearable devices such as smart watches, smart glasses, headphones, pendants, earphones, and the like. In general, the term “mobile device” can be broadly defined to encompass any electronic, computing, and / or telecommunications device (and / or combination of devices) that is easily carried by a user and capable of wireless communication using WLAN or Wi-Fi.

[0037] Wireless Device (and / or Wireless Station)—Any of various types of computer system devices that perform wireless communications using WLAN communications. As used herein, the term “wireless device” may refer to a mobile device as defined above, or a stationary device such as a stationary wireless client or wireless base station. For example, a wireless device may be any type of wireless station in an 802.11 system, such as an access point (AP) or a client station (STA or UE). Further examples include televisions, media players (e.g., AppleTV™, Roku™, Amazon FireTV™, Google Chromecast™, etc.), refrigerators, washing machines, thermostats, etc.

[0038] WLAN - The term "WLAN" has the full scope of its ordinary meaning and includes at least a wireless communication network or RAT served by WLAN access points and providing connectivity to the Internet through these access points. Modern WLANs are based on the IEEE 802.11 standard and are marketed under the name "Wi-Fi." WLAN networks are distinct from cellular networks.

[0039] Processing Element—refers to various implementations of digital circuitry that performs a function within a computer system. In addition, processing element may refer to various implementations of analog or mixed-signal (combination of analog and digital) circuitry that performs a function(s) within a computer or computer system. Processing elements include, for example, circuitry such as an integrated circuit (IC), an application specific integrated circuit (ASIC), a portion or circuitry of an individual processor core, an entire processor core, an individual processor, a programmable hardware device such as a field programmable gate array (FPGA), and / or a larger portion of a system that includes multiple processors.

[0040] Automatically—refers to an action or operation being performed by a computer system (e.g., software executed by a computer system) or device (e.g., circuitry, programmable hardware element, ASIC, etc.) without user input directly specifying or executing the action or operation. Thus, the term “automatically” is in contrast to an operation that is manually performed or specified by a user, in which the user provides input to directly perform the operation. An automatic procedure may be initiated by user-provided input, but subsequent actions performed “automatically” are not specified by the user, e.g., not performed “manually,” in which the user specifies each action to be performed. For example, a user filling out an electronic form by selecting each field and providing input specifying information (e.g., by typing information, selecting checkboxes, selecting radio selections, etc.) is considered manually filling out the form, even though the computer system must update the form in response to the user actions. A form may also be automatically filled out by a computer system, in which the computer system (e.g., software executed by the computer system) analyzes the form's fields and fills out the form without user input specifying answers to the fields. As noted above, a user can invoke automatic form filling but is not involved in the actual filling of the form (e.g., the user does not manually specify answers in fields, but rather the answers are completed automatically). This specification provides various examples of actions that are automatically performed in response to actions taken by a user.

[0041] Concurrent—refers to parallel execution or implementation, in which tasks, processes, signaling, messaging, or programs are executed in an at least partially overlapping manner. For example, concurrent execution may be performed using “strong” or strict parallelism, in which tasks are executed (at least partially) in parallel on respective computational elements, or “weak parallelism,” in which tasks are executed in an interleaved manner, e.g., by time-division multiplexing of execution threads.

[0042] Configured to—Various components may be described as being “configured to” perform a task. In this context, “configured to” is a broad description that generally means “having a structure” to perform a task or tasks during operation. Thus, a component may be configured to perform a task even when the component is not currently performing the task (e.g., a set of conductors may be configured to electrically connect a module to another module even when the two modules are not connected). In some contexts, “configured to” may be a broad description of a structure that generally means “having circuitry” to perform a task or tasks during operation. Thus, a component may be configured to perform a task even when the component is not currently on. Generally, the circuitry forming the structure corresponding to “configured to” may include hardware circuitry.

[0043] In the description herein, for convenience, various components may be described as performing a task or tasks. Such descriptions should be construed to include the phrase "configured to." It is expressly intended that a description of a component being configured to perform one or more tasks does not invoke 35 U.S.C. 112(f) interpretation with respect to that component. Figures 1 and 2 - Wireless communication system

[0044] Figure 1 illustrates an exemplary (and simplified) wireless communication system in which aspects of the present disclosure may be implemented. It should be noted that the system of Figure 1 is merely one example of a possible system, and that embodiments of the disclosure may be implemented in any of a variety of systems as desired.

[0045] As shown, the exemplary wireless communication system includes a (“first”) wireless device 102 in communication with another (“second”) wireless device 104. The first wireless device 102 and the second wireless device 104 may communicate wirelessly using any of a variety of wireless communication technologies, possibly including ranging wireless communication technologies.

[0046] As one possibility, the first wireless device 102 and the second wireless device 104 may perform ranging using wireless local area network (WLAN) communication technology (e.g., IEEE 802.11 / Wi-Fi based communication) and / or technology based on WLAN wireless communication. One or both of the wireless devices 102 and 104 may also be capable of communicating via one or more additional wireless communication protocols, such as any of Bluetooth (BT), Bluetooth Low Energy (BLE), Near Field Communication (NFC), LTE, LTE-ADVANCED (LTE-A), NR, Ultra Wideband (UWB), etc.

[0047] Wireless devices 102 and 104 may be any of a variety of types of wireless devices. As one possibility, one or more of wireless devices 102 and / or 104 may be a substantially portable wireless user equipment (UE) device, such as a smartphone, a handheld device, a wearable device such as a smart watch, a tablet, an automobile, or virtually any type of wireless device. As another possibility, one or more of wireless devices 102 and / or 104 may be a substantially stationary device, such as a set-top box, a media player (e.g., an audio or audiovisual device), a game console, a desktop computer, an appliance, a door, an access point, a base station, or any of a variety of other types of devices.

[0048] Each of the wireless devices 102 and 104 may include wireless communication circuitry configured to facilitate wireless communication, which may include various digital and / or analog radio frequency (RF) components, programmable hardware elements such as memory, field programmable gate arrays (FPGAs), and / or processors configured to execute program instructions stored in any of various other components. The wireless devices 102 and / or 104 may use some or all of such components to perform any of the method embodiments described herein, or any portion of any of the method embodiments described herein.

[0049] Each of the wireless devices 102 and 104 may include one or more antennas for communicating using one or more wireless communication protocols. In some cases, one or more portions of the receive and / or transmit chains may be shared among multiple wireless communication standards. For example, a device may be configured to communicate using either Bluetooth® or Wi-Fi® using partially or fully shared wireless communication circuitry (e.g., using a shared radio or at least shared radio components). The shared communication circuitry may include a single antenna or multiple antennas (e.g., for MIMO) to perform wireless communication. Alternatively, a device may include separate transmit and / or receive chains (e.g., including separate antennas and other radio components) for each wireless communication protocol configured to communicate with the device. As a further possibility, a device may include one or more radios or radio components shared among multiple wireless communication protocols and one or more radios or radio components used exclusively by a single wireless communication protocol. For example, a device may include a shared radio for communicating using one or more of LTE and / or 5G NR and separate radios for communicating using each of Wi-Fi, UWB, and Bluetooth. Other configurations are possible.

[0050] As mentioned above, aspects of the present disclosure may be implemented in conjunction with the wireless communication system of Figure 1. For example, a wireless device (e.g., either wireless device 102 or 104) may be configured to perform methods for robust discovery of new access points (APs) in an AP MLD, robust link addition to an AP MLD association, AP beacon mode when an AP is added to or removed from an AP MLD, and robust BSS transition management (BTM) signaling to steer non-AP MLDs to the best AP MLD and most suitable AP, as well as privacy improvements for associated non-AP MLDs.

[0051] 6 illustrates an exemplary wireless device 100 (e.g., corresponding to wireless devices 102 and / or 104) that may be configured for use with various aspects of the present disclosure. Device 100 may be any of a variety of types of device and may be configured to perform any of a variety of types of functionality. Device 100 may be a substantially portable device or a substantially stationary device, which may include any of a variety of types of device. Device 100 may be configured to perform one or more ranging wireless communication techniques or features, such as any of the techniques or features shown and / or described later herein with respect to some or all of the figures.

[0052] As shown, device 100 may include a processing element 101. The processing element may include or be coupled to one or more memory devices. For example, device 100 may include one or more memory media (e.g., memory 105), which may include any of a variety of types of memory and perform any of a variety of functions. For example, memory 105 may be RAM that serves as system memory for processing element 101. Other types and functions are also possible.

[0053] Additionally, device 100 may include wireless communication circuitry 130. The wireless communication circuitry may include any of a variety of communication elements (e.g., wireless communication antenna(s), analog and / or digital communication circuitry / controllers, etc.) and may enable the device to communicate wirelessly using one or more wireless communication protocols.

[0054] It should be noted that in some cases, wireless communication circuitry 130 may include its own processing element (e.g., a baseband processor), for example, in addition to processing element 101. For example, processing element 101 may be an "application processor" whose primary function may support application layer operations within device 100, while wireless communication circuitry 130 may be a "baseband processor" whose primary function may support baseband layer operations within device 100 (e.g., to facilitate wireless communication between device 100 and other devices). In other words, in some cases, device 100 may include multiple processing elements (e.g., may be a multiprocessor device). Other configurations utilizing a multiprocessor architecture are also possible (e.g., instead of or in addition to an application processor / baseband processor configuration).

[0055] Depending on the intended functionality of device 100, device 100 may additionally include any of a variety of other components (not shown) for achieving device functionality, which may include further processing and / or memory elements (e.g., audio processing circuitry), one or more power elements (which may rely on battery power and / or an external power source), user interface elements (e.g., a display, speaker, microphone, camera, keyboard, mouse, touch screen, etc.), and / or any of a variety of other components.

[0056] Components of device 100, such as processing element 101, memory 105, and wireless communication circuitry 130, may be operably coupled via one or more interconnection interfaces, which may include any of a variety of types of interfaces, and in some cases may include a combination of multiple types of interfaces. As one example, a USB high-speed inter-chip (HSIC) interface may be provided for inter-chip communication between processing elements. Alternatively (and / or additionally), a universal asynchronous receiver-transmitter (UART) interface, a serial peripheral interface (SPI), an inter-integrated circuit (I2C), a system management bus (SMBus), and / or any of a variety of other communication interfaces may be used for communication between the various device components. Other types of interfaces (e.g., intra-chip interfaces for communication within processing element 101, peripheral interfaces for communication with peripheral components internal or external to device 100, etc.) may also be provided as part of device 100. Figure 3 - WLAN system

[0057] 3 illustrates an exemplary WLAN system according to some embodiments. As shown, the exemplary WLAN system includes multiple wireless client stations or devices (e.g., STAs or user equipment (UE)) 106 configured to communicate with an access point (AP) 112 over a wireless communication channel 142. The AP 112 may be a Wi-Fi access point. The AP 112 may communicate with one or more other electronic devices (not shown) and / or another network 152, such as the Internet, over a wired and / or wireless communication channel 150. Additional electronic devices, such as a remote device 154, may communicate with components of the WLAN system over the network 152. For example, the remote device 154 may be another wireless client station, a server associated with an application running on one of the STAs 106, or the like. The WLAN system may be configured to operate according to any of a variety of communication standards, such as various IEEE 802.11 standards. In some embodiments, at least one wireless device 106 is configured to communicate directly with one or more neighboring mobile devices without using the access point 112.

[0058] Furthermore, in some embodiments, wireless device 106 (which may be an example implementation of device 100) may be configured to perform methods for robust discovery of new access points (APs) in AP MLDs, robust link addition to AP MLD associations, AP beacon mode when APs are added to or removed from AP MLDs, and robust BSS transition management (BTM) signaling to steer non-AP MLDs to the best AP MLD and most suitable AP, as well as privacy improvements for associated non-AP MLDs. Figure 4 - Access Point Block Diagram

[0059] 4 shows an example block diagram of an access point (AP) 112, which may be one possible example implementation of the device 100 shown in FIG. 4. It should be noted that the AP block diagram in FIG. 4 is merely one example of a possible system. As shown, the AP 112 may include a processor(s) 204 that can execute program instructions for the AP 112. The processor(s) 204 may also be coupled (directly or indirectly) to a memory management unit (MMU) 240, which may be configured to receive addresses from the processor(s) 204 and translate those addresses to locations in memory (e.g., memory 260 and read-only memory (ROM) 250) or to locations in other circuits or devices.

[0060] The AP 112 may include at least one network port 270. The network port 270 may be configured to couple to a wired network and provide access to the Internet for multiple devices, such as the mobile device 106. For example, the network port 270 (or additional network ports) may be configured to couple to a local network, such as a home network or an enterprise network. For example, the port 270 may be an Ethernet port. The local network may provide connectivity to additional networks, such as the Internet.

[0061] The AP 112 may be configured to operate as a wireless transceiver and may include at least one antenna 234, which may be configured to communicate with the mobile device 106 via wireless communication circuitry 230. The antenna 234 communicates with the wireless communication circuitry 230 via a communication chain 232. The communication chain 232 may include one or more receive chains, one or more transmit chains, or both. The wireless communication circuitry 230 may be configured to communicate via 802.11 Wi-Fi or WLAN, for example. The wireless communication circuitry 230 may also, or instead, be configured to communicate via various other wireless communication technologies, including, but not limited to, Long Term Evolution (LTE), LTE Advanced (LTE-A), 5G NR, etc., for example, when the AP is co-located with a base station in the case of a small cell, or in other cases where it may be desirable for the AP 112 to communicate via various different wireless communication technologies.

[0062] Additionally, in some embodiments, as described further below, AP 112 may be configured to perform methods for robust discovery of new access points (APs) in AP MLDs, robust link addition to AP MLD associations, AP beacon mode when APs are added to or removed from AP MLDs, and robust BSS transition management (BTM) signaling to steer non-AP MLDs to the best AP MLD and most suitable AP, as well as privacy improvements for associated non-AP MLDs. Figure 5 - Client station block diagram

[0063] 5 shows an exemplary simplified block diagram of a client station 106, which may be one possible exemplary implementation of the device 100 shown in FIG. 4. According to an embodiment, the client station 106 may be a user equipment (UE) device, a mobile device or station, and / or a wireless device or station. As shown, the client station 106 may include a system-on-chip (SOC) 300, which may include portions for various purposes. The SOC 300 may be coupled to various other circuits of the client station 106. For example, the client station 106 may include various types of memory (e.g., including NAND flash memory 310), a connector interface (I / F) (and / or dock) 320 (e.g., for coupling to a computer system, dock, charging station, etc.), a display 360, cellular communication circuitry (e.g., a cellular radio) 330 for 5G NR, LTE, etc., and near-medium range wireless communication circuitry (e.g., a Bluetooth® / WLAN radio) 329 (e.g., Bluetooth™ and WLAN circuitry). The client station 106 may further include one or more smart cards 315 incorporating SIM (Subscriber Identity Module) functionality, such as one or more UICCs (Universal Integrated Circuit(s)). The cellular communication circuitry 330 may be coupled to one or more antennas, such as antennas 335 and 336, as shown. The near-medium range wireless communication circuitry 329 may also be coupled to one or more antennas, such as antennas 337 and 338, as shown. Alternatively, the near-medium range wireless communication circuitry 329 may be coupled to antennas 337 and 338 in addition to or instead of being coupled to antennas 335 and 336. The near-medium range wireless communication circuitry 329 may include multiple receive chains and / or multiple transmit chains for receiving and / or transmitting multiple spatial streams, such as in a Multiple-Input Multiple Output (MIMO) configuration. Some or all components of the near-medium range wireless communication circuitry 329 and / or cellular communication circuitry 330 may be used for ranging communications, for example, using WLAN, Bluetooth, and / or cellular communications.

[0064] As shown, SOC 300 may include processor(s) 302 capable of executing program instructions for client station 106, and display circuitry 304 capable of performing graphics processing and providing display signals to display 360. SOC 300 may also include motion sensing circuitry 370 capable of detecting movement of client station 106 using, for example, a gyroscope, an accelerometer, and / or any of a variety of other motion sensing components. The processor(s) 302 may be coupled to a memory management unit (MMU) 340, which may be configured to receive addresses from the processor(s) 302 and translate these addresses to locations in memory (e.g., memory 306, read only memory (ROM) 350, NAND flash memory 310) and / or to other circuits or devices, such as display circuitry 304, cellular communication circuitry 330, near field communication circuitry 329, connector interface (I / F) 320, and / or display 360. The MMU 340 may be configured to perform memory protection and page table translation or setup. In some embodiments, the MMU 340 may be included as part of the processor(s) 302.

[0065] As mentioned above, the client station 106 may be configured to communicate directly over the air with one or more neighboring client stations. The client station 106 may be configured to communicate according to a WLAN RAT for communication in a WLAN network such as that shown in FIG. 3 or for ranging such as that shown in FIG.

[0066] As described herein, the client station 106 may include hardware and software components for implementing the functionality described herein. For example, the processor 302 of the client station 106 may be configured to implement some or all of the functionality described herein, for example, by executing program instructions stored on a storage medium (e.g., a non-transitory computer-readable storage medium). Alternatively (and / or in addition), the processor 302 may be configured as a programmable hardware element, such as a field programmable gate array (FPGA), or as an application specific integrated circuit (ASIC). Alternatively (and / or in addition), the processor 302 of the UE 106 may be configured to implement some or all of the functionality described herein in cooperation with one or more of the other components 300, 304, 306, 310, 315, 320, 329, 330, 335, 336, 337, 338, 340, 350, 360, and 370.

[0067] Additionally, as described herein, processor 302 may include one or more processing elements. Accordingly, processor 302 may include one or more integrated circuits (ICs) configured to perform the functions of processor 302. Additionally, each integrated circuit may include circuitry (e.g., a first circuit, a second circuit, etc.) configured to perform the functions of processor(s) 204.

[0068] Further, as described herein, the cellular communication circuit 330 and the near field communication circuit 329 may each include one or more processing elements. In other words, one or more processing elements may be included in the cellular communication circuit 330 and also in the near field communication circuit 329. Thus, the cellular communication circuit 330 and the near field communication circuit 329 may each include one or more integrated circuits (ICs) configured to perform the functions of the cellular communication circuit 330 and the near field communication circuit 329, respectively. In addition, each integrated circuit may include circuits (e.g., a first circuit, a second circuit, etc.) configured to perform the functions of the cellular communication circuit 330 and the near field communication circuit 329. Figure 6 - Wireless node block diagram

[0069] FIG. 6 illustrates one possible block diagram of a wireless node 107, which may be one possible exemplary implementation of the device 100 shown in FIG. 6. As shown, the wireless node 107 may include a system-on-chip (SOC) 400, which may include portions for various purposes. For example, as shown, the SOC 400 may include a processor(s) 402 that may execute program instructions for the wireless node 107 and a display circuit 404 that may perform graphics processing and provide display signals to a display 460. The SOC 400 may also include a motion sensing circuit 470 that may detect movement of the wireless node 107, for example, using a gyroscope, an accelerometer, and / or any of a variety of other motion sensing components. The processor(s) 402 may also be coupled to a memory management unit (MMU) 440, which may be configured to receive addresses from the processor(s) 402 and translate those addresses into locations in memory (e.g., memory 406, read only memory (ROM) 450, flash memory 410). The MMU 440 may be configured to perform memory protection and page table translation or setup. In some embodiments, the MMU 440 may be included as part of the processor(s) 402.

[0070] As shown, the SOC 400 may be coupled to various other circuits of the wireless node 107. For example, the wireless node 107 may include various types of memory (including, e.g., NAND flash 310), a connector interface 420 (e.g., for coupling to a computer system, a dock, a charging station, etc.), a display 460, and wireless communication circuitry 430 (e.g., for 5G NR, LTE, LTE-A, Bluetooth, Wi-Fi, NFC, etc.).

[0071] The wireless node 107 may include at least one antenna, and in some embodiments multiple antennas 435 and 436, to perform wireless communications with base stations and / or other devices. For example, the wireless node 107 may perform wireless communications using the antennas 435 and 436. As mentioned above, the wireless node 107 may in some embodiments be configured to communicate wirelessly using multiple wireless communication standards or radio access technologies (RATs).

[0072] The wireless communication circuitry 430 may include Wi-Fi logic 432, a cellular modem 434, and Bluetooth logic 439. The Wi-Fi logic 432 enables the wireless node 107 to perform Wi-Fi communications, for example, over an 802.11 network. The Bluetooth logic 439 enables the wireless node 107 to perform Bluetooth communications. The cellular modem 434 may enable cellular communications according to one or more cellular communication technologies. Some or all of the components of the wireless communication circuitry 430 may be used for ranging communications, for example, using WLAN, Bluetooth, and / or cellular communications.

[0073] As described herein, a wireless node 107 may include hardware and software components for implementing embodiments of the present disclosure. For example, one or more components of the wireless communication circuitry 430 (e.g., Wi-Fi logic 432) of a wireless node 107 may be configured to perform some or all of the methods described herein, for example, by a processor executing program instructions stored on a storage medium (e.g., a non-transitory computer-readable storage medium), a processor configured as an FPGA (Field Programmable Gate Array), and / or using dedicated hardware components, which may include an ASIC (Application Specific Integrated Circuit). Figures 7 and 8 - Multi-Link Device (MLD) Operation

[0074] One or more IEEE 802.11 releases, such as IEEE 802.11bi, may include multi-link device (MLD) capabilities. In current implementations, an access point (AP) multi-link device (MLD) node can manage its associated APs. Thus, an AP MLD node can modify, add, and / or subtract associated APs to increase capacity and manage basic service set (BSS) interference and coverage, including switching APs to operate on channels with less interference, and / or steer associated non-AP MLD nodes to operate on better performing APs and / or AP MLD nodes.

[0075] 7 illustrates AP MLD 112, according to some embodiments. An AP MLD can operate with any number of affiliated APs, e.g., APs 712a, 712b, 712c, and 712d in the illustrated example. The affiliated APs can operate in any of a variety of frequency bands. The affiliated APs can operate in different frequency ranges (e.g., channels) of the same band or in different frequency bands.

[0076] AP MLD can serve affiliated APs from a single physical device, e.g., a single shared housing, potentially using the same antenna(s). In some embodiments, AP MLD can serve APs from multiple separate devices (e.g., a first device can serve one or more APs, a second device can serve a different one or more APs, etc.). In some embodiments, the various affiliated APs can be spatially separated (e.g., using beams in different directions, using different antennas with shared housing (e.g., antennas of the same physical device) and / or antennas of different devices, etc.).

[0077] In some embodiments, spatially separated affiliated APs may operate on the same (or overlapping) channel(s).

[0078] FIG. 8 illustrates an AP MLD 112 in communication with a non-AP MLD 106, according to some embodiments.

[0079] As shown, the AP MLD 112 can operate three affiliated APs. In the illustrated example, AP 812a can operate in the 2.4 GHz band, AP 812b can operate in the 5 GHz band, and AP 812c can operate in the 6 GHz band. It will be understood that any number of affiliated APs can be used in any combination of bands. For example, an AP MLD can operate multiple affiliated APs in a band and / or in some cases, no affiliated APs can operate in a band. The affiliated APs can include various layers, e.g., a medium access control (MAC) layer and / or a physical (PHY) layer, among other possibilities. The affiliated APs can use different basic service sets (BSSs) and / or different BSS identifiers (BSSIDs), e.g., BSSIDs 1-3.

[0080] As shown, the non-AP MLD 106 may operate three associated STAs corresponding to, for example, three associated APs. In the illustrated example, STA 806a may operate in the 2.4 GHz band, STA 806b may operate in the 5 GHz band, and STA 806c may operate in the 6 GHz band. The STAs may communicate with their corresponding APs. It will be understood that any number of associated STAs may be used in any combination of bands. For example, a non-AP MLD may operate multiple associated STAs in a band and / or in some cases, may not operate any associated STAs in a band. A non-AP MLD may operate STAs corresponding to some or all of the APs of the AP MLD. The associated STAs may include various layers, e.g., the PHY layer and / or the MAC layer, among other possibilities. The associated STAs may use different addresses, e.g., Addr 1-3.

[0081] Non-AP MLD can serve associated STAs from a single physical device, e.g., a single shared housing, potentially using the same antenna(s). In some embodiments, non-AP MLD can serve STAs from multiple separate devices (e.g., a first device can serve one or more STAs, a second device can serve a different one or more STAs, etc.). In some embodiments, various associated STAs can be spatially separated (e.g., using beams in different directions, using different antennas with shared housing (e.g., antennas of the same physical device) and / or antennas of different devices, etc.).

[0082] Various affiliated STAs and APs may communicate in parallel / concurrently. For example, STA 806a may exchange uplink and / or downlink data with AP 812a over a first link, STA 806b may exchange uplink and / or downlink data with AP 812b over a second link, etc. It will be appreciated that such concurrent communications may include (e.g., different) data exchanged simultaneously, at overlapping times, and / or at different times over different links. For example, data between an AP MLD and a non-AP MLD may be routed via a first available link and / or a link selected based on other criteria (e.g., lowest energy usage, etc.). For example, a first packet or portion of data may be transmitted over a first link, and simultaneously a second packet or portion of data may be transmitted over a second link.

[0083] In some embodiments, the AP MLD and non-AP MLD may include respective ML entities. The ML entities may provide higher level MAC functions that control separate APs and / or STAs, e.g., control traffic distribution over available links between various APs and STAs. Each MLD (e.g., AP and non-AP) may have only one respective MAC SAP interface. The ML entities may manage this interface. The ML entities may manage transmit buffering (e.g., bookkeeping and link selection at the transmitter) and data reordering buffering at the receiver (e.g., combining data transmitted on different links).

[0084] The AP MLD 112 and the non-AP MLD 106 may exchange information about their respective operations, operating parameters, and / or capabilities.

[0085] Non-AP MLD may have various capabilities for operating STAs in a particular band. The capabilities may be different for different bands. For example, the capabilities in a band may describe the maximum (e.g., fastest, most flexible, most powerful, highest throughput, etc.) parameter values ​​that a non-AP MLD STA can use. The operations or operation parameters may describe parameter values ​​that are currently being used or will be used in the future.

[0086] For example, the parameters may include applicable PHY versions and their parameters. The parameters may describe supported services and available transmission formats. The parameters may also describe available resources, bandwidth, and the number of spatial streams. The parameters may describe power saving support parameters that may enable low-power transmissions. For example, an AP may support target wake time (TWT) power saving.

[0087] In some embodiments, links may be located so closely together (e.g., spatially and / or in frequency) that non-AP STAs may not operate them independently (e.g., due to device limitations and / or to manage resources or performance). An AP may support STAs that cannot simultaneously transmit and receive on a link pair (e.g., non-AP MLD).

[0088] In some embodiments, a non-AP MLD can operate a STA that communicates with multiple AP MLDs. For example, a first STA can communicate with a first AP MLD, and a second STA can communicate with a second AP MLD. Similarly, an AP MLD can communicate with multiple STAs. For example, one affiliated AP can communicate with multiple STAs.

[0089] In the illustrated example, non-AP MLD serves a number of STAs equal to the number of APs served by AP MLD. However, different numbers are possible. For example, AP MLD may serve more APs than the number of STAs served by non-AP MLD, or vice versa. The number of APs and / or the number of STAs may change over time.

[0090] According to some embodiments, it may be beneficial for a client privacy-enhanced (CPE) station (STA) or client to change or adjust certain parameters used to communicate with an AP. For example, an eavesdropper may attempt to intercept, extract, or listen in on communications between a particular CPE STA and an AP. Therefore, a client may seek to more secure communications between the CPE STA and the AP using various techniques, including address changes or related parameter adjustments.

[0091] For example, when a CPE client reassociates from one CPE AP to another, it may be beneficial for it to change its own over-the-air (OTA) medium access control (MAC) address used to communicate with the AP. Additionally or alternatively, it may be beneficial for the CPE client to initiate a change of its own OTA MAC address used with a CPE AP in an associated state (e.g., STA State 4) without losing connectivity. In some embodiments, it may be beneficial for the CPE client to simultaneously initiate an OTA MAC address change for all associated CPE clients in a base station system (BSS) (e.g., CPE clients in associated STA State 4) without losing connectivity. Furthermore, according to some embodiments, it may be beneficial for the CPE client and CPE AP to change transmitted sequence numbers (SNs), packet numbers (PNs), and transaction identifiers (TIDs) to uncorrelated new values ​​on the downlink and to new values ​​on the uplink for the associated STA State 4 without losing connectivity. Additionally, it may be further beneficial for the CPE client and CPE AP to change the CPE client's Association Identifier (AID) to a new, uncorrelated value in Associated STA State 4 without losing connectivity. Power Management for Multilink Operation

[0092] In recent Wi-Fi releases, power management (PM) mode changes are performed on a per-link basis due to unsupported cross-link PM mode changes. For example, if a non-AP MLD wanted to enter power save (PS) mode on all links, the non-AP MLD and AP MLD had to perform separate frame exchanges (to change PM mode) over each enabled link. However, this per-link frame exchange (e.g., separate frame exchanges) to change PM mode is inefficient and can potentially cause long delays to enter PS mode, which allows non-AP MLD STAs to enter a sleep (e.g., doze) state. 9A-9C—Legacy Method for MLD PM Mode Change for STR and EMLSR Link Scenarios

[0093] 9A-9C illustrate a legacy method for PM mode changes for MLD, according to some embodiments. For example, the method of FIG. 9A may be applicable, according to some embodiments, to a first exemplary scenario involving three simultaneous transmit / receive (STR) links and switching delays experienced when changing PM modes. Additionally, FIGS. 9B-9C illustrate different scenarios involving EMLSR and potential latency issues experienced when changing PM modes, according to some embodiments.

[0094] 9A shows a separate frame exchange on each link to change the PM mode of all links (links L1, L2, and L3) between the non-AP MLD (including STA-1, STA-2, and STA-3) and the AP MLD (including AP-1, AP-2, and AP-3). For example, for the non-AP MLD to transition to or from a sleep state at time T0, the non-AP MLD would need to send a PM indication (e.g., PM=1 corresponding to PS mode or PM=0 corresponding to a change from PS mode to active mode) over each link at an earlier time (according to legacy methods). However, in some cases, this would cause AP-1 and AP-2 to stop sending DL traffic earlier than necessary (e.g., between Δt-1 and Δt-2), thus preventing L1 and L2 from being used by the non-AP MLD and the AP MLD during these periods. For example, STA-2 may transmit a QoS Null message (QN), which may include a PM change indication, and then receive an acknowledgement (ACK) from AP-2. Thus, according to some embodiments, the time from receiving the ACK to transitioning to (or from) a sleep state may be characterized by Δt.

[0095] Furthermore, when link-1 is no longer busy, STA-1 may also transmit a QN and receive an ACK from AP-1, and after time Δt−1 (e.g., at t=T0) has elapsed, STA-1 may also transition to or from a sleep state (e.g., in PS mode). Similarly, at t=T0, after STA-3 is no longer busy and transmits a QN and receives an ACK from AP-3, STA-3 may also transition to or from PS mode (e.g., to active mode). Thus, at time t=T0, it can be assumed that all of the STAs are in a power save and sleep state (or in an active state if PM=0, corresponding to a change from PS mode to active mode, is received). Furthermore, according to some embodiments, L1, L2, and L3 may all be STR links, operating in the 2.4 GHz, 5 GHz, and 6 GHz frequency bands, respectively. In other words, FIG. 9A shows the legacy way how multiple STAs in a non-AP MLD can be transitioned to or from PS mode (e.g., to active mode) via separate PM signaling on each link with the AP MLD.

[0096] 9B illustrates a second exemplary scenario involving a PM mode change, where L1 is an STR link and L2 and L3 are EMLSR links, according to some embodiments. Similar to the first scenario, due to EMLSR limitations, there may be extra latency (e.g., EMLSR switching delay) for frame exchange in the UL over the EMLSR link for PM indications. For example, for a non-AP MLD to transition to or from PS mode (e.g., to active mode) on its EMLSR link and remain awake on the STR link (L1, 2.4 GHz link), it may be necessary for STA-2 and STA-3 to send PM indications separately for each link (according to legacy methods), which may further require a contention procedure for each link and switching between EMLSR links to change PM, according to some embodiments.

[0097] Thus, FIG. 9B illustrates separate frame exchanges on L2 and L3 between the non-AP MLD (including STA-1, STA-2, and STA-3) and the AP MLD (including AP-1, AP-2, and AP-3) to change the PM mode (L2 and L3) of these links. For example, for STA-2 and STA-3 to transition to a sleep state (e.g., PS mode), the non-AP MLD (according to legacy methods) needs to send a PM indication (e.g., PM=1 corresponding to PS mode, or PM=0 corresponding to a change from PS mode to active mode) over L2 and L3. For example, when STA-2 is no longer busy, STA-2 can send a QN that can include a PM change indication and then receive an ACK from AP-2. Furthermore, according to some embodiments, there can be a switching delay between the time the ACK is received and the time STA-2 transitions from active mode to PS mode.

[0098] Similarly, when STA-3 is no longer busy, STA-3 can also transmit a QN, receive an ACK from AP-3, and then transition to or from PS mode (e.g., to active mode). Thus, according to some embodiments, there may be a latency (e.g., a time delay) from the time non-AP MLD determines to transition STA-2 and STA-3 from their respective active mode to or from PS mode (e.g., to active mode). In other words, as shown in FIG. 9B, for STA-2 and STA-3 to transition to sleep mode at t=T0, the PS mode indication should be transmitted earlier so that no DL traffic is received from that time until t=T0.

[0099] 9C illustrates a third exemplary scenario involving a PM mode change in which L1 is an STR link and L2 and L3 are EMLSR links, according to some embodiments. However, if L3 is very busy, it may be beneficial to operate L2 as a single-link EMLSR (SL EMLSR), according to some embodiments. For example, transitioning the SL EMLSR to a power-save mode instead of explicitly enabling / disabling the EMLSR link (e.g., L3) through an Enhanced Multilink (EML) Operational Mode Notification (OMN) frame exchange may result in a more efficient use of non-AP MLD resources and / or power. Therefore, to transition STA-3 to or from PS mode (e.g., to active mode), the non-AP MLD may need to switch to the busy link (L3) and send a QN to change the PM mode (after receiving an ACK). 9B, according to some embodiments, there may be a latency or time delay from the time that non-AP MLD decides to transition STA-3 from active mode to PS mode or from PS mode (e.g., to active mode). In summary, Figures 9A-9C illustrate various aspects of the latency and inefficiency problems experienced with per-link (e.g., separate) PM signaling used in legacy methods.

[0100] Therefore, several proposals are being considered for the latest Wi-Fi releases (e.g., Wi-Fi 7). For example, according to some embodiments, cross-link PM mode changes for non-AP MLD may be possible through the use of the A-Control field to avoid having to perform a separate frame exchange. Furthermore, one bit of the A-Control field may be used to indicate the PM mode, and an 8-bit bitmap of the A-Control field may be used to indicate the link identifier (ID) to which the PM change applies.

[0101] These proposals allow for immediate crosslink information delivery, although there is a non-negligible crosslink information exchange delay between APs in AP MLD. For example, according to some embodiments, a scheduled multilink (ML) PM mode indication with timing information can be introduced to address the crosslink information exchange delay between APs in AP MLD. Furthermore, according to some embodiments, it may be beneficial for the non-AP MLD to include duration information for STAs that remain in PS mode (or vice versa for switching to active mode) when the non-AP MLD switches to PS mode.

[0102] Therefore, the methods described below detail multi-link PM mode change scenarios and enhanced techniques that can enable faster and more efficient PM mode changes between links. For example, the enhanced techniques include an AP MLD informing associated non-AP MLDs of its expected cross-link information exchange delay, so that the non-AP MLDs can provide appropriately scheduled PM mode indications to assist the AP MLDs in meeting the cross-link information exchange delay. Figure 10-11 - Extended method for power management of MLD

[0103] 10 and 11 are communication flow diagrams illustrating enhanced methods of power management techniques for MLDs, according to some embodiments. Such techniques can help provide a more efficient method (compared to legacy methods) for reducing power consumption between AP MLDs and non-AP MLDs.

[0104] For example, Figure 10 illustrates an exemplary enhanced method for a power management technique performed by a non-AP MLD, according to some embodiments. Aspects of the method of Figure 10 can be implemented by a non-AP MLD in communication with an AP MLD. The AP MLD and / or the non-AP MLD may be as shown and described with respect to various of the figures herein, or more generally, may be in conjunction with any of the computer circuits, systems, devices, elements, or components shown in the above figures, among others, as desired. For example, the processor (and / or other hardware) of such a device may be configured to cause the device to perform any combination of the method elements shown in the figures and / or other method elements. For example, one or more processors (or processing elements) (e.g., processor(s) associated with communication circuitry such as processor(s) 101, 204, 302, 402, 432, 434, 439, baseband processor(s), 130, 230, 232, 329, 330, 430, among other possibilities) may cause a wireless device, STA, UE, non-AP, and / or AP, or other device, to perform such method elements.

[0105] It should be noted that, although at least some elements of the method of Figure 10 are described as relating to the use of communication techniques and / or features associated with IEEE and / or 802.11 (e.g., 802.11be) standards, such description is not intended to limit the disclosure, and aspects of the method of Figure 10 may be used in any suitable wireless communication system, as desired. Similarly, while elements of the method of Figure 10 are described in a manner related to a non-AP that may be an MLD, such description is not intended to limit the disclosure, and aspects of the method of Figure 10 may be used by a non-AP that is not an MLD, as desired.

[0106] The illustrated method may be used in conjunction with any of the systems, methods, or devices shown in the figures, among other devices. In various embodiments, some of the illustrated method elements may be performed simultaneously, in a different order than that shown, or may be omitted. Additional method elements may be performed as desired. As shown in the figures, the method may operate as follows.

[0107] At 1002, according to some embodiments, the non-AP MLD can establish a wireless link with the AP MLD. For example, the non-AP MLD can establish at least two wireless links with the AP MLD, including a group of at least two APs, over an access channel. According to some embodiments, establishing the wireless link can include an association procedure. For example, according to some embodiments, the non-AP MLD can scan for target APs (which may be included in the AP MLD) using active scanning or passive scanning. Thus, the non-AP MLD can send a probe request to one or more target AP(s) as a way to scan for available AP(s). In some embodiments, the target AP(s) can send a probe response to the non-AP MLD. Using this additional information, the non-AP MLD can send an association request to the target AP. Furthermore, the non-AP MLD can receive an association response from the target AP as part of the association and / or roaming procedure. According to some embodiments, the AP MLD can send expected crosslink information exchange delay information to the non-AP MLD during the association procedure.

[0108] At 1004, according to some embodiments, the non-AP MLD may receive first timing information from the AP MLD. For example, the non-AP MLD may receive crosslink information exchange timing information from the AP MLD. This crosslink information exchange timing information may correspond to the time required for the AP MLD to exchange signaling or provide instructions across its multiple APs. In some embodiments, the AP MLD's expected crosslink information exchange delay may be transmitted to the non-AP MLD through an EML OMN request and response procedure.

[0109] At 1006, according to some embodiments, the non-AP MLD may determine second timing information. For example, the non-AP MLD may determine second timing information for the at least two wireless links based at least in part on the first timing information. In some embodiments, the second timing information may include a timing synchronization function (TSF). Additionally or alternatively, the second timing information may include or indicate a timing offset associated with a time at which one or more non-AP STAs transition to the PS mode or the active mode.

[0110] At 1008, according to some embodiments, the non-AP MLD may transmit a power management indication (PMI) frame to the AP MLD. For example, the non-AP MLD may transmit a frame to a first AP of the at least two APs, the frame including at least one link identifier (ID), at least one indication of a power management (PM) mode, and the timing offset information determined at 1006. In some embodiments, the second timing information may be characterized as a timing offset between transmitting the frame and a time when one or more non-AP STAs transition to or from a PS mode (e.g., to an active mode). Furthermore, according to some embodiments, the frame may further include duration information corresponding to a duration for which the one or more non-AP STAs are in the PS mode. Furthermore, the frame may be a PMI frame, and the indication of the PM mode may be a bit value equal to 1 indicating a transition of one or more non-AP stations to the PS mode or the active mode.

[0111] According to some embodiments, the frame may be transmitted using A-control field signaling. In some embodiments, the A-control field signaling may include at least one of an 8-bit Link ID subfield, a 1-bit PM Mode subfield, an 8-bit Timing Offset subfield, an 8-bit Duration subfield, or a 1-bit Reserved subfield. According to some embodiments, the A-control field signaling may be included in a Medium Access Control Protocol Data Unit (MPDU), a Control Response (CR) frame, or a Quality of Service Null (QN) frame.

[0112] At 1010, according to some embodiments, the non-AP MLD may receive an ACK frame from the AP MLD. For example, the non-AP MLD may receive the ACK frame from a first AP of the AP MLD. Further, following receipt of the ACK frame, one or more non-AP stations (STAs) of the non-AP MLD transition to or from a power save (PS) mode (e.g., to an active mode) at a time associated with the second timing information based on at least one link ID (e.g., a link ID associated with at least one of the wireless links) and an indication of a PM mode (e.g., a PM mode indicator).

[0113] Additionally, Figure 11 illustrates an exemplary method for an enhanced power management technique performed by an AP MLD, according to some embodiments. Aspects of the method of Figure 11 may be implemented by an AP MLD in communication with a non-AP MLD. The AP MLD and / or the non-AP MLD may be as shown and described with respect to various of the figures herein, or more generally, may be in conjunction with any of the computer circuits, systems, devices, elements, or components shown in the above figures, among others, as desired. For example, the processor (and / or other hardware) of such a device may be configured to cause the device to perform any combination of the method elements illustrated in the figures and / or other method elements. For example, one or more processors (or processing elements) (e.g., processor(s) associated with communication circuitry such as processor(s) 101, 204, 302, 402, 432, 434, 439, baseband processor(s), 130, 230, 232, 329, 330, 430, among other possibilities) may cause a wireless device, STA, UE, non-AP, and / or AP, or other device, to perform such method elements.

[0114] It should be noted that, although at least some elements of the method of Figure 11 are described as relating to the use of communication techniques and / or features associated with IEEE and / or 802.11 (e.g., 802.11be) standards, such description is not intended to limit the disclosure, and aspects of the method of Figure 11 may be used in any suitable wireless communication system, if desired. Similarly, while elements of the method of Figure 11 are described in a manner related to an AP that may be an MLD, such description is not intended to limit the disclosure, and aspects of the method of Figure 11 may be used by an AP that is not an MLD, if desired.

[0115] The illustrated method may be used in conjunction with any of the systems, methods, or devices shown in the figures, among other devices. In various embodiments, some of the illustrated method elements may be performed simultaneously, in a different order than that shown, or may be omitted. Additional method elements may be performed as desired. As shown in the figures, the method may operate as follows.

[0116] At 1102, according to some embodiments, the AP MLD can establish a wireless link with a non-AP MLD. In some instances, the AP MLD can establish at least two wireless links with a non-access point (non-AP) multilink device (MLD) comprising a group of at least two non-AP stations (STAs) over an access channel. According to some embodiments, establishing the wireless link can include an association procedure. For example, according to some embodiments, the non-AP MLD can scan for a target AP (which may be included in the AP MLD) using active scanning or passive scanning. Thus, the non-AP MLD can send a probe request to one or more target AP(s) as a way to scan for available AP(s). In some embodiments, the target AP(s) of the AP MLD can send a probe response to the non-AP MLD. Using this additional information, the non-AP MLD can send an association request to the target AP(s) of the AP MLD. Furthermore, the non-AP MLD can receive an association response from the AP MLD as part of the association and / or roaming procedure. According to some embodiments, the AP MLD may transmit expected crosslink information exchange delay information to the non-AP MLD during the association procedure.

[0117] At 1104, according to some embodiments, the AP MLD may transmit first timing information to the non-AP MLD. According to some embodiments, the AP MLD may transmit crosslink information exchange timing information to the non-AP MLD as part of the first timing information. This crosslink information exchange timing information may correspond to the time required for the AP MLD to exchange signaling or provide instructions across its multiple APs. In some embodiments, the AP MLD's expected crosslink information exchange delay may be transmitted to the non-AP MLD through an EML OMN request and response procedure.

[0118] According to some embodiments, at 1106, the AP MLD may receive a frame from the non-AP MLD. In some instances, the AP MLD may receive a frame from the non-AP MLD including at least one link identifier (ID) of at least two wireless links (e.g., a link ID associated with at least one of the wireless links), an indication of a power management (PM) mode, and second timing information. Further, the frame may be a power management indication (PMI) frame, and the indication of the PM mode may be a bit value equal to 1 indicating a transition of one or more non-AP stations into or out of a PS mode (e.g., to an active mode). In some embodiments, the second timing information may include a timing synchronization function (TSF). According to some embodiments, the second timing information may be characterized as a timing offset between the AP MLD receiving the frame and a time at which one or more non-AP STAs transition into or out of a PS mode (e.g., to an active mode). Furthermore, according to some embodiments, the frame may further include duration information corresponding to a duration for which one or more non-AP STAs are in a PS mode. Additionally or alternatively, the second timing information may include or indicate a timing offset associated with the time at which one or more non-AP STAs transition into or out of PS mode (e.g., to active mode).

[0119] According to some embodiments, the frame can be received via A-control field signaling. In some embodiments, the A-control field signaling can include at least one of an 8-bit Link ID subfield, a 1-bit PM Mode subfield, an 8-bit Timing Offset subfield, an 8-bit Duration subfield, or a 1-bit Reserved subfield. According to some embodiments, the A-control field signaling can be included in a Medium Access Control Protocol Data Unit (MPDU), a Control Response (CR) frame, or a Quality of Service Null (QN) frame.

[0120] At 1108, according to some embodiments, the AP MLD may send an ACK frame to the non-AP MLD. According to some embodiments, the ACK frame may be sent from the AP MLD to the non-AP MLD to acknowledge receipt of the frame received at 1106.

[0121] At 1110, according to some embodiments, the AP MLD may determine that one or more STAs of the non-AP MLD are in a PS mode. In some instances, the AP MLD may determine that one or more of the at least two non-AP STAs transitioned to or from a power save (PS) mode (e.g., to an active mode) at a time associated with the second timing information based on the at least one link ID and the indication of the PM mode.

[0122] In some embodiments, the AP MLD may provide at least one link ID and an indication of the PM mode to one or more of the at least two wireless links via crosslink signaling. Additionally, the AP MLD may refrain from communicating with one or more non-AP STAs while the one or more non-AP STAs are in the PS mode. According to some embodiments, the at least two wireless links may be simultaneous transmit / receive (STR) links. In other embodiments, one or more of the at least two wireless links may be enhanced multi-link single-radio (EMLSR) links or single-link enhanced multi-link single-radio (SL-EMLSR) links. Figure 12 – Scheduled Multilink PM Signaling

[0123] Figure 12 shows an example format for enhanced scheduled multilink PM mode indication signaling according to some embodiments. For example, in conjunction with the methods shown by Figures 10 and 11, scheduled multilink PM mode indication signaling can enable multilink PM mode indication through a single frame exchange, which can reduce PM mode change overhead and latency, according to some embodiments.

[0124] Thus, multiple fields within the scheduled multilink PM mode indication signaling can be used to indicate parameters related to the scheduled PM mode change. For example, as shown in FIG. 12, according to some embodiments, fields within the scheduled multilink PM mode indication signaling can include bits allocated to indicate link ID, per-link PM bits, presence control, schedule timing, and duration (which may be optional fields). In some instances, fields in the scheduled multilink PM mode indication signaling can include per-link PM indications (and associated link ID(s) (e.g., associated with at least one of the wireless links)) in addition to presence control, schedule timing, and duration fields. In some embodiments, the schedule timing field can correspond to or indicate a future time at which the PM mode change should be applied. For example, a non-AP MLD can use the "schedule timing" field to provide a scheduled PM mode change indication to an AP MLD in the future. According to some embodiments, this schedule timing indication can be absolute timing (e.g., timing synchronization function (TSF)) or a time offset. Furthermore, according to some embodiments, multilink PM signaling information can be carried in a version of the signaling within the control frame or A-control field.

[0125] In some embodiments, the non-AP MLD may have previously received the AP MLD's expected crosslink information exchange delay. For example, this crosslink information exchange delay / timing information may have been sent to the non-AP MLD during association, during beacons, or via an EML OMN request and response mechanism or exchange. Thus, according to some embodiments, the non-AP MLD can use the crosslink information exchange delay / timing information to set the "schedule timing" field to meet the AP MLD's crosslink information exchange delay. Additionally or alternatively, the non-AP MLD may use the duration field to indicate the duration for which the STA (associated with the link ID) should remain in PS mode (or reciprocally active mode). In other words, to reduce extra signaling overhead, the non-AP MLD can use the duration field of the scheduled multilink PM mode indication signaling to indicate the duration for which the STA will remain in PS mode before returning to active mode. By including this optional field, this can reduce signaling overhead by not having to send an additional frame with an indication of PM=0 to instruct the STA to return to active mode, according to some embodiments.

[0126] According to some embodiments, the scheduled multilink PM mode indication signaling can be a power management indicator (PMI) frame. Further, according to some embodiments, the PMI frame can be a new control frame transmitted as a standalone frame with a sufficient total number of bits available to allow the STA to access and transmit on the channel. 13A-13C—Extended method for ML PM mode change for STR and EMLSR link scenarios

[0127] 13A-13C illustrate an enhanced method for ML PM mode changes for STR and EMLSR link scenarios, according to some embodiments. For example, FIG. 13A may correspond to a first exemplary scenario involving three STR links and reduced switching delays when changing PM modes in accordance with enhanced power management techniques, according to some embodiments. Additionally, FIG. 13B-13C illustrate a different scenario involving EMLSR and the potential latency reductions possible when changing PM modes using enhanced power management techniques, according to some embodiments.

[0128] 13A shows a single frame exchange on one link to change the PM mode for STAs associated with all links (links L1, L2, and L3) between a non-AP MLD (including STA-1, STA-2, and STA-3) and an AP MLD (including AP-1, AP-2, and AP-3). In other words, rather than having to send a separate QN message (and receive an ACK) for each link to transition them to or from PS mode (e.g., to active mode), FIG. 13A shows an enhanced technique involving three STR links and reduced switching delay when changing PM modes. For example, for STA-1, STA-2, and STA-3 to go to a sleep state (e.g., PS mode) at time T0 (e.g., t=T0), the non-AP MLD can send a PM indication (PMI) frame over one link (e.g., L2), which can then use cross-link PM signaling to provide the appropriate information from the PMI frame to the other link (L1, L3). As described above with respect to FIG. 12, according to some embodiments, the PMI frame may include fields for indicating a link ID, a PM bit for each link, presence control, schedule timing, and duration. For example, the PMI frame may include fields indicating PM=1 for L1, L2, and L3, such that all of the STAs associated with these links should transition from active mode to PS mode. Alternatively, according to some embodiments, fields indicating PM=0 for L1, L2, and L3 indicate that all of the STAs associated with these links should transition from PS mode to active mode. The PMI frame may also include timing information regarding the change of PM modes for STA-1, STA-2, and STA-3.

[0129] For example, FIG. 13A shows AP-2 receiving a PMI including PM=1 for L1, L2, and L3, along with timing information related to a change in PM mode. This allows AP-2 to send an ACK to STA-2 to acknowledge receipt of the PMI frame. Furthermore, the timing information may correspond to a timing offset associated with the time between the PMI being received and the time t=T0 at which all of the STAs should be considered to be in PS mode and a sleep state (e.g., characterized by being in PS mode and a sleep state). In other words, the timing offset may correspond to a period for STA-1, STA-2, and STA-3 to transition into or out of PS mode (e.g., to active mode) after the AP MLD receives the PMI frame. Furthermore, according to some embodiments, AP-2 can utilize this time window (e.g., timing offset) to provide the PM mode change information (contained in the PMI) to other links (e.g., L1 and L3) via crosslink signaling. Therefore, once AP-1 and AP-3 receive the appropriate PMI information via crosslink signaling, all three STAs can be characterized as being in PS mode at time t=T0.

[0130] Additionally, it may be beneficial to address AP MLD architectures that do not consider MLD between 2.4 GHz and 5 GHz or 6 GHz. For example, some AP MLDs do not consider 2.4 GHz links as part of their MLD architecture, and therefore cross-link information exchange latency between 2.4 GHz links and 5 GHz or 6 GHz AP links may be much longer. To accommodate such architectures, the AP MLD may indicate only links that support cross-link signaling (e.g., not all enabled links in some cases).

[0131] Furthermore, according to some embodiments, the maximum crosslink information exchange delay requirement can be utilized by non-AP MLD. For example, if the crosslink information exchange delay is very long, non-AP MLD may not be able to benefit from scheduled multilink PM indications and instead may have to contend for each link separately to indicate a PM mode change. Thus, according to some embodiments, if the crosslink information exchange delay requirement is defined to be less than the maximum physical protocol data unit (PPDU) duration (e.g., 5.4 ms), this may be useful for non-AP MLD to have a sufficient amount of time to perform a PM mode change across the appropriate links.

[0132] Furthermore, according to some embodiments, a non-AP MLD STA can use the PM bit in the frame control field for the same link with multilink PM. For example, similar to the legacy method described in Figures 9A-9C, a non-AP MLD STA can perform a PM mode change based on the PM bit in the frame control field immediately after receiving an ACK.

[0133] Furthermore, according to some embodiments, to prevent race conditions, if a STA operating on one link in non-AP MLD sends a crosslink PM mode change on behalf of another STA, the other STA may send PM bits over its own link as long as the PM value is the same PM value as the PM value sent in the crosslink PM signaling.

[0134] FIG. 13B illustrates a second example scenario involving a PM mode change, where L1 is an STR link and L2 and L3 are EMLSR links, according to some embodiments. For example, FIG. 13B shows AP-1 receiving a PMI including PM=1 for L2 and L3, along with timing information related to a change in PM mode. This allows AP-1 to send an ACK to STA-1 to acknowledge receipt of the PMI frame. Furthermore, the timing information may correspond to a timing offset associated with the time between the PMI being received and the time t=T0 at which STA-2 and STA-3 should be in PS mode. In other words, the timing offset may correspond to a period of time for STA-2 and STA-3 to transition into or out of PS mode (e.g., to active mode) after the AP MLD receives the PMI frame. Furthermore, according to some embodiments, AP-1 can utilize this timing offset window to provide PM mode change information (contained in the PMI) to other links (e.g., L2 and L3) via crosslink signaling. Thus, once AP-2 and AP-3 receive the appropriate PMI information via crosslink signaling, STA-2 and STA-3 can be characterized as being in PS mode at time t=T0.

[0135] FIG. 13C illustrates a third exemplary scenario involving a PM mode change, in which L1 is an STR link and L2 and L3 are EMLSR links, according to some embodiments. However, if L3 is very busy, it may be beneficial to have L2 operate as an SL EMLSR, according to some embodiments. For example, transitioning the SL EMLSR to or from PS mode (e.g., to active mode) instead of explicitly enabling / disabling the EMLSR link (e.g., L3) via an EML OMN frame exchange may be a more efficient use of non-AP MLD resources and / or power. Thus, to transition STA-3 to or from PS mode (e.g., to active mode), FIG. 13B shows AP-2 receiving a PMI including PM=1 for L3 (or PM=0, corresponding to a change from PS mode to active mode) in addition to timing information regarding the PM mode change. This allows AP-2 to send an ACK to STA-2 to acknowledge receipt of the PMI frame. Furthermore, the timing information included in the PMI frame may correspond to a timing offset associated with the time between the PMI being received by AP-2 and the time t=T0 at which STA-3 should be in PS mode. In other words, the timing offset may correspond to a period of time for L3 to transition to or from PS mode (e.g., to active mode) after AP-2 receives the PMI frame. Furthermore, according to some embodiments, AP-2 can utilize this timing offset window to provide PM mode change information (included in the PMI) to AP-3 via crosslink signaling. Thus, once AP-3 receives the appropriate PMI information via crosslink signaling, according to some embodiments, STA-3 can be considered to be in PS mode at time t=T0, and STA-2 can perform as a SL-EM LSR on L2 after t=T0. 14A-14D—SIGNALING OPTIONS FOR EXTENDED POWER MANAGEMENT OF MLD

[0136] 14A-14D illustrate signaling options and aspects for an enhanced method of PM for MLD, according to some embodiments. For example, FIG. 14A illustrates an example format of an A-control field that may be used in PM mode change indication signaling, according to some embodiments. Furthermore, FIG. 14A illustrates a more compact and / or lighter-weight (e.g., smaller memory size) version or format of the signaling (compared to that of FIG. 12) that may be used in A-control field signaling. Accordingly, this smaller format may be beneficial, according to some embodiments, by allowing it to be included in a media access control (MAC) protocol data unit (MPDU) used by a STA as a transmit opportunity (TXOP) initiator, or alternatively, in a control response (CR) frame used by a STA as a TXOP responder. For example, FIG. 14A illustrates an A-control field signaling format that includes 8 bits for a link ID and 1 bit for a PM mode indication. According to some embodiments, up to eight links can be supported in an MLD device, and thus one bit for PM mode and eight bits for link indication can enable independent per-link PM mode changes (up to eight links). Further, according to some embodiments, the A control field signaling format can include an advance timing indication within the timing offset subfield. For example, a timing offset subfield with eight bits and 64 μs resolution can provide maximum timing information up to 16.3 ms, and a duration field with eight bits and 512 μs resolution can provide a maximum duration up to 131 ms.

[0137] According to some embodiments, the A-control field signaling format can be considered a lighter version of signaling compared to the extended scheduled multilink PM mode indication signaling shown in FIG. 12. For example, as shown in FIG. 14A, according to some embodiments, the A-control subfield can use only 26 bits. Therefore, the A-control field signaling format cannot fit all fields that may be present in the multilink PM mode indication signaling shown in FIG. 12, such as a PMI frame. Therefore, duration and presence control are not present in the A-control field signaling format, and the number of bits for link ID, PM mode, and timing offset in the A-control field signaling format is fewer than the number of bits in a PMI frame. However, according to some embodiments, the A-control field signaling can be implicitly added to the MPDU (as part of the MPDU MAC header) and transmitted to the AP in the UL. Alternatively, according to some embodiments, the A-control field signaling can be added in a control response (CR) frame (e.g., a block acknowledgement (BA) frame).

[0138] For example, Figure 14B illustrates a first exemplary scenario in which a STA is the TXOP initiator, according to some embodiments. Furthermore, Figure 14B illustrates how A-control field signaling can be included in an MPDU when the STA is the initiator of the TXOP. For example, according to some embodiments, the STA can include an ML PM indication (via the A-control field) in a data transmission from the STA to the AP. Accordingly, the AP can transmit a Block Acknowledgement (BA) to the STA to acknowledge receipt of the data transmission (and thus the ML PM indication).

[0139] 14C illustrates a second exemplary scenario in which a STA is a TXOP responder, according to some embodiments. Furthermore, FIG. 14C illustrates how A-control field signaling can be included in a CR frame when the STA is a TXOP responder. For example, according to some embodiments, an AP can transmit data to a STA, and the STA can respond via a CR frame. Furthermore, the STA can include an ML PM indication (via the A-control field) in the CR frame to provide an ML PM indication to the AP.

[0140] 14D illustrates a third exemplary scenario in which A-control field signaling may be included in a QN frame transmitted by a STA, according to some embodiments. For example, the STA may transmit a QN frame and include an ML PM indication in the QN frame using the lighter A-control field format described in FIG. 14A. Thus, the AP may send an ACK to the STA to acknowledge receipt of the QN (and thus the ML PM indication). Figure 15 - Leaky AP issue

[0141] 15 illustrates an example scenario involving PM between AP MLD and non-AP MLD, where AP MLD has a "leaky" AP problem, according to some embodiments. For example, when a STA provides PMI to an AP and the STA transitions to or from PS mode (e.g., PM=1) or from PS mode (e.g., PM=0 corresponding to active mode), it may take time for the AP to take the STA's PM=1 indication into account, so the AP can continue to send DL traffic. However, because the indicated STA is considered to be in PS mode and in a sleep state, the DL traffic cannot be properly received by the STA. Therefore, it may be beneficial to prevent unnecessary or unhelpful DL transmissions to STAs in PS mode.

[0142] For example, when a non-AP MLD provides PMI (including scheduled timing information) to an AP MLD, the AP MLD can know the time (e.g., t=T0) at which the indicated STA will enter PS mode. Thus, according to some embodiments, the AP MLD should not transmit packets to STAs indicated to be in PS mode after the scheduled time (e.g., after T0). For example, with respect to FIG. 15, after T0, STA-2 and STA-3 can be considered to be in PS mode and in a sleep state. Therefore, it may be beneficial for the AP MLD to ensure that packets are not transmitted to STA-2 and STA-3 in the DL while they are in PS mode.

[0143] Furthermore, efficiently exiting PS mode or transitioning back to active mode is also an important aspect to consider. For example, it may be undesirable for the AP MLD to take a significant amount of time before it can deliver packets on all links. In other words, it may be more beneficial for the AP MLD to know how long the STAs are in PS mode so that it can be ready to transmit data as soon as the STAs exit PS mode. In some embodiments, the optional duration field in the scheduled ML PM signaling shown in FIG. 12 can assist in such a scenario, such that the AP MLD can transmit packets to the STAs on all links after this duration (e.g., after the STA(s) enter active mode). Furthermore, according to some embodiments, the STA indicates the duration for which it will remain in PS mode, but can still transmit a frame including an active mode indication if it decides to exit PS mode sooner. In other words, when the STA transitions from a sleep state to an awake state, the STA can inform the AP that it is in active mode (e.g., an awake state).

[0144] Furthermore, while the above examples and figures describe embodiments directed primarily to transitioning from active mode to PS mode (e.g., via a PM=1 indication), additional embodiments are contemplated. For example, the techniques described herein may also be applied to embodiments directed to transitioning from PS mode to active mode (e.g., via a PM=0 indication). Illustrative Embodiments

[0145] In some embodiments, a method may include establishing at least two wireless links with an access point (AP) multilink device (MLD) comprising at least a first AP and a second AP, and receiving signaling from the AP MLD, the signaling including first timing information. The method may include determining second timing information based on the first timing information, and transmitting a frame including a link identifier (ID) associated with at least one of the at least two wireless links, a power management (PM) mode indicator, and the second timing information. Further, the method may include receiving an acknowledgement (ACK) frame, where after receiving the ACK frame, based on the link ID and the PM mode indicator, one or more non-AP stations (STAs) in the non-AP MLD transition to a power save (PS) mode at a time associated with the second timing information.

[0146] According to some embodiments, the second timing information may include a timing synchronization function (TSF). Further, according to some embodiments, the first timing information may include crosslink information exchange timing between any two APs in an AP MLD. According to some embodiments, the crosslink information exchange timing may be received during one of an association procedure, a beacon procedure, or an enhanced multilink (EML) operational mode notification (OMN) request and response mechanism. In some embodiments, the signaling may include information indicating which of the at least two radio links supports crosslink signaling. Also, the second timing information may include an absolute timing synchronization function (TSF) or a timing offset between the time the frame is transmitted and the time one or more non-AP STAs transition to PS mode. According to further embodiments, the frame may further include duration information associated with the duration of time one or more non-AP STAs are in PS mode. Furthermore, the frame may be a power management indication (PMI) frame.

[0147] In some embodiments, an apparatus may include a processor configured, when executing instructions stored in a memory, to cause a non-access point (non-AP) multilink device (MLD) comprising one or more non-access point (non-AP) stations (STAs) to perform operations including establishing at least two wireless links with an access point (AP) MLD comprising at least a first AP and a second AP. The operations may further include receiving signaling from the AP MLD including first timing information and determining second timing information based at least in part on the first timing information. The operations may further include transmitting a frame to the AP MLD including at least one link identifier (ID) associated with at least one of the at least two wireless links, a power management (PM) mode indicator, at least a portion of the second timing information, and duration information. The operations may further include, according to some embodiments, receiving an acknowledgement (ACK) frame from the first AP MLD, and after receiving the ACK frame, based at least in part on the at least one link ID and the PM mode indicator, one or more non-AP STAs of the non-AP MLD transition from a power save (PS) mode to an active mode at a time associated with the second timing information.

[0148] According to some embodiments, the PM mode indicator may be a bit value equal to 0 to indicate a transition of one or more non-AP STAs to an active mode. Additionally or alternatively, the frame may be transmitted using A-control field signaling. In some embodiments, the A-control field signaling may include at least one of an 8-bit Link ID subfield, a 1-bit PM Mode subfield, an 8-bit Timing Offset subfield, an 8-bit Duration subfield, or a 1-bit Reserved subfield. According to some embodiments, the A-control field signaling may be included in a Medium Access Control Protocol Data Unit (MPDU), a Control Response (CR) frame, or a Quality of Service Null (QN) frame.

[0149] According to another embodiment, a method may include establishing at least two wireless links with a non-AP multilink device (MLD) comprising at least two non-access point (non-AP) stations (STAs). The method may further include transmitting signaling comprising first timing information to the non-AP MLD and receiving a frame from the non-AP MLD including at least one link identifier (ID) associated with at least one of the at least two wireless links, a power management (PM) mode indicator, and second timing information. Further, the method may include transmitting an acknowledgement (ACK) frame to the non-AP MLD and determining, based at least in part on the at least one link ID and the PM mode indicator, that one or more non-AP STAs of the non-AP MLD transition to a power save (PS) mode at a time associated with the second timing information.

[0150] In some embodiments, the method may include providing at least one link ID and a PM mode indicator to one or more of the at least two wireless links via crosslink signaling. Further, the method may include refraining from communicating with one or more non-AP STAs while the one or more non-AP STAs are in the PS mode. According to some embodiments, the at least two wireless links may be simultaneous transmit / receive (STR) links. In other embodiments, one or more of the at least two wireless links may be enhanced multi-link single-radio (EMLSR) links or single-link enhanced multi-link single-radio (SL-EMLSR) links. Furthermore, the first timing information may include crosslink information exchange timing between at least any two APs of the AP. Furthermore, according to some embodiments, the crosslink information exchange timing may be received during one of an association procedure, a beacon procedure, or an enhanced multi-link (EML) operational mode notification (OMN) request and response mechanism.

[0151] Embodiments of the present disclosure may be implemented in any of a variety of forms. For example, some embodiments may be implemented as a computer-implemented method, a computer-readable storage medium, or a computer system. Other embodiments may be implemented using one or more custom-designed hardware devices, such as an ASIC. Other embodiments may be implemented using one or more programmable hardware elements, such as an FPGA.

[0152] In some embodiments, a non-transitory computer-readable storage medium may be configured to store program instructions and / or data that, when executed by a computer system, cause the computer system to perform the method, e.g., any of the method embodiments described herein, or a combination of the method embodiments described herein, or a subset of the method embodiments described herein, or a combination of such subsets.

[0153] In some embodiments, a wireless device may be configured to include a processor (and / or set of processors) and a storage medium, where the storage medium stores program instructions, and the processor is configured to read and execute the program instructions from the storage medium, and the program instructions are executable to cause the wireless device to implement any of the various method embodiments described herein (or a combination of the method embodiments described herein, or any subset of any of the method embodiments described herein, or any combination of such subsets). The device may be implemented in any of a variety of forms.

[0154] Although the above embodiments have been described in considerable detail, numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated, and it is intended that the following claims be interpreted to embrace all such variations and modifications.

Claims

1. 1. A method comprising: A non-access point (non-AP) multilink device (MLD) comprising one or more non-access point (non-AP) stations (STAs), Establishing at least two wireless links with an access point (AP) MLD, the AP comprising at least a first AP and a second AP; receiving signaling from the AP MLD, the signaling including first timing information; determining second timing information based at least in part on the first timing information; transmitting to the first AP a frame including at least one link identifier (ID) associated with at least one of the at least two wireless links, a power management (PM) mode indicator, and at least a portion of the second timing information; receiving an acknowledgement (ACK) frame from the first AP, wherein after receiving the ACK frame, the one or more non-AP STAs of the non-AP MLD transition to a power save (PS) mode at a time associated with the second timing information based at least in part on the at least one link ID and the PM mode indicator.

2. The method of claim 1 , wherein the second timing information includes a timing synchronization function (TSF).

3. The method of claim 1 , wherein the first timing information includes cross-link information exchange timing between at least any two APs in the AP MLD.

4. The timing of the crosslink information exchange is Association procedure, Beacon procedure, or 4. The method of claim 3, wherein the received signal is received during one of an Enhanced Multilink (EML) Operational Mode Notification (OMN) request and response mechanism.

5. The method of claim 1 , wherein the signaling further includes information indicating which of the at least two wireless links supports cross-link signaling.

6. 2. The method of claim 1, wherein the second timing information includes a timing offset or an absolute timing synchronization function (TSF) between a time when the frame is transmitted and a time when the one or more non-AP STAs transition to the PS mode.

7. The method of claim 1 , wherein the frame further includes duration information associated with a duration of time the one or more non-AP STAs are in the PS mode.

8. The method of claim 1 , wherein the frame is a power management indication (PMI) frame.

9. 1. An apparatus comprising: a processor that, when executing instructions stored in a memory, causes a non-access point (non-AP) multi-link device (MLD) comprising one or more non-AP stations (STAs) to: Establishing at least two wireless links with an access point (AP) MLD, the AP comprising at least a first AP and a second AP; receiving signaling from the AP MLD, the signaling including first timing information; determining second timing information based at least in part on the first timing information; transmitting to the first AP MLD a frame including at least one link identifier (ID) associated with at least one of the at least two wireless links, a power management (PM) mode indicator, at least a portion of the second timing information, and duration information; receiving an acknowledgement (ACK) frame from the first AP MLD, wherein after receiving the ACK frame, the one or more non-AP STAs of the non-AP MLD transition from a power save (PS) mode to an active mode at a time associated with the second timing information based at least in part on the at least one link ID and the PM mode indicator.

10. 10. The apparatus of claim 9, wherein the PM mode indicator is a bit value equal to 0 to indicate the transition of the one or more non-AP STAs to the active mode.

11. The apparatus of claim 9 , wherein the frame is transmitted using A-control field signaling.

12. The A control field signaling includes: an 8-bit Link ID subfield, a 1-bit PM mode subfield, an 8-bit timing offset subfield; an 8-bit duration subfield, or 12. The apparatus of claim 11, further comprising at least one of: a 1-bit reserved subfield;

13. The A control field signaling includes: Medium Access Control Protocol Data Unit (MPDU), a control response (CR) frame, or 12. The apparatus of claim 11, wherein the quality of service is included in one of: a quality of service null (QN) frame.

14. 1. A method comprising: Establishing at least two wireless links with a non-AP multi-link device (MLD) comprising at least two non-access point (non-AP) stations (STAs); transmitting signaling including first timing information to the non-AP MLD; receiving a frame from the non-AP MLD, the frame including at least one link identifier (ID) associated with at least one of the at least two wireless links, a power management (PM) mode indicator, and second timing information; sending an acknowledgement (ACK) frame to the non-AP MLD; determining, based at least in part on the at least one link ID and the PM mode indicator, that one or more non-AP STAs of the non-AP MLD transition to a power save (PS) mode at a time associated with the second timing information; A method comprising:

15. providing the at least one link ID and the PM mode indicator to one or more of the at least two wireless links via crosslink signaling; The method of claim 14 further comprising:

16. refraining from communicating with the one or more non-AP STAs while the one or more non-AP STAs are in the PS mode; The method of claim 14 further comprising:

17. 15. The method of claim 14, wherein the at least two wireless links are simultaneous transmit / receive (STR) links.

18. 15. The method of claim 14, wherein one or more of the at least two wireless links is an Enhanced Multi-Link Single Radio (EMLSR) link.

19. 20. The method of claim 18, wherein one or more of the at least two wireless links is a Single Link Enhanced Multi-Link Single Radio (SL-EMLSR) link.

20. The first timing information includes a cross-link information exchange timing between at least any two APs of the APs, and the cross-link information exchange timing includes: Association procedure, Beacon procedure, or 15. The method of claim 14, wherein the received signal is received during one of an Enhanced Multilink (EML) Operational Mode Notification (OMN) request and response mechanism.

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