Patent Publication Number: US-2023133701-A1

Title: Target wake for multi-link operation restrictions

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATION(S) 
     This application claims the benefit of U.S. Provisional Application No. 63/356,898, filed Jun. 29, 2022, the disclosure of which is incorporated by reference as set forth in full. 
    
    
     TECHNICAL FIELD 
     This disclosure generally relates to systems and methods for wireless communications and, more particularly, to target wake time (TWT) for multi-link operation (MLO) restrictions. 
     BACKGROUND 
     Wireless devices are becoming widely prevalent and are increasingly requesting access to wireless channels. The Institute of Electrical and Electronics Engineers (IEEE) is developing one or more standards that utilize Orthogonal Frequency-Division Multiple Access (OFDMA) in channel allocation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a network diagram illustrating an example network environment for target wake time (TWT) for multi-link operation (MLO), in accordance with one or more example embodiments of the present disclosure. 
         FIG.  2    illustrates a flow diagram of a process for an illustrative TWT for MLO system, in accordance with one or more example embodiments of the present disclosure. 
         FIG.  3    illustrates a functional diagram of an exemplary communication station that may be suitable for use as a user device, in accordance with one or more example embodiments of the present disclosure. 
         FIG.  4    illustrates a block diagram of an example machine upon which any of one or more techniques (e.g., methods) may be performed, in accordance with one or more example embodiments of the present disclosure. 
         FIG.  5    is a block diagram of a radio architecture in accordance with some examples. 
         FIG.  6    illustrates an example front-end module circuitry for use in the radio architecture of  FIG.  5   , in accordance with one or more example embodiments of the present disclosure. 
         FIG.  7    illustrates an example radio IC circuitry for use in the radio architecture of  FIG.  5   , in accordance with one or more example embodiments of the present disclosure. 
         FIG.  8    illustrates an example baseband processing circuitry for use in the radio architecture of  FIG.  5   , in accordance with one or more example embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The following description and the drawings sufficiently illustrate specific embodiments to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, algorithm, and other changes. Portions and features of some embodiments may be included in, or substituted for, those of other embodiments. Embodiments set forth in the claims encompass all available equivalents of those claims. 
     Devices will have more and more specific latency-sensitive traffic to send, defined as traffic that needs to be successfully transmitted within a particular service period (with a specific delay bound). 
     Restricted TWT (rTWT) is defined for this purpose in IEEE 802.11be (“Ube”) standard. This is the same as a TWT agreement, except that there are specific rules to follow for all STAs in the BSS supporting rTWT to follow, specifically stopping an ongoing TxOP at the beginning of the rTWT SP, in order to force a contention period at the start of the TWT SP. There are also ways to define the type of traffic that will be transmitted by the AP or the STA during the service period (define for DL and for UL—what are the TIDs that are going to be prioritized). How will that work with multi-link operation that is also defined in 11be. 
     TWT is a function that permits an AP to define a specific time or set of times for individual stations to access the medium. The STA (client) and the AP exchange information that includes an expected activity duration to allow the AP to control the amount of contention and overlap among competing STAs. The AP can protect the expected duration of activity with various protection mechanisms. The use of TWT is negotiated between an AP and an STA. Target Wake Time may be used to reduce network energy consumption, as stations that use it can enter a doze state until their TWT arrives. 
     Currently, rTWT has been defined to be per communication link and is therefore orthogonal to multi-link operation (e.g., in an MLD situation). However, there are cases where restrictions due to Multi-link operation may impact operation with rTWT. For instance:
         If a device is a non-simultaneous transmit-receive (NSTR) device, it cannot transmit (TX) on one link and receive (RX) on the other link. However, it can receive on both links.   If that device has established an rTWT for DL traffic on one link, it would not be able to send UL traffic on the other link during that time.   If that device has established an rTWT on one link, it will want to make sure that it can be fully available for reception or transmission on that link and therefore will want that the AP on the other link is not transmitting or triggering the STA in UL during the rTWT period.   If a device is enhanced multilink single radio (eMLSR), it can receive on both links, but when an AP starts an eMLSR TXOP to communicate with that non-AP MLD on one link, that non-AP MLD will no longer be able to receive anything on the other link.   If that device has established an rTWT on one link (link 1), it wants to be available at the beginning of the rTWT on that link and therefore does not want the other link to be having an eMLSR TxOP that will overlap with the rTWT on that link. There are currently no ways to get protection on that front.       

     Example embodiments of the present disclosure relate to systems, methods, and devices for target wake time (TWT) and restricted TWT (rTWT) for multi-link operation (MLO) restrictions. 
     In one or more embodiments, a TWT for MLO system may facilitate that an rTWT initiator STA (e.g., a non-AP STA of an MLD) can send to an rTWT responder STA (e.g., an AP of an MLD) an rTWT element in an unsolicited TWT setup frame (response frame) that will inform the responder STA that during the TWT service period (SP) that is described in the rTWT element, the initiator STA will not be available for specific operations. Under one specific mode, the initiator STA will not be available, meaning that the two STAs (initiator and responder) will have to end TxOP before the start of the rTWT SP and won&#39;t be allowed to initiate a TxOP or transmit to the peer or schedule the peer for transmission during the rTWT SP. 
     In one or more embodiments, under one specific mode, the initiator STA will only be available for transmission or reception, but under specific restrictions for instance if there is an ongoing TxOP between the two peer MLDs on another link (case of NSTR for instance), then the start and end of PPDUs alignment will be required between the two links and the same direction will be required (downlink (DL) on link 1 and 2, or uplink (UL) on link 1 and 2). 
     The above descriptions are for purposes of illustration and are not meant to be limiting. Numerous other examples, configurations, processes, algorithms, etc., may exist, some of which are described in greater detail below. Example embodiments will now be described with reference to the accompanying figures. 
       FIG.  1    is a network diagram illustrating an example network environment of TWT for MLO, according to some example embodiments of the present disclosure. Wireless network  100  may include one or more user devices  120  and one or more access points(s) (AP)  102 , which may communicate in accordance with IEEE 802.11 communication standards. The user device(s)  120  may be mobile devices that are non-stationary (e.g., not having fixed locations) or may be stationary devices. 
     In some embodiments, the user devices  120  and the AP  102  may include one or more computer systems similar to that of the functional diagram of  FIG.  3    and/or the example machine/system of  FIG.  4   . 
     One or more illustrative user device(s)  120  and/or AP(s)  102  may be operable by one or more user(s)  110 . It should be noted that any addressable unit may be a station (STA). An STA may take on multiple distinct characteristics, each of which shape its function. For example, a single addressable unit might simultaneously be a portable STA, a quality-of-service (QoS) STA, a dependent STA, and a hidden STA. The one or more illustrative user device(s)  120  and the AP(s)  102  may be STAs. The one or more illustrative user device(s)  120  and/or AP(s)  102  may operate as a personal basic service set (PBSS) control point/access point (PCP/AP). The user device(s)  120  (e.g.,  124 ,  126 , or  128 ) and/or AP(s)  102  may include any suitable processor-driven device including, but not limited to, a mobile device or a non-mobile, e.g., a static device. For example, user device(s)  120  and/or AP(s)  102  may include, a user equipment (UE), a station (STA), an access point (AP), a software enabled AP (SoftAP), a personal computer (PC), a wearable wireless device (e.g., bracelet, watch, glasses, ring, etc.), a desktop computer, a mobile computer, a laptop computer, an Ultrabook™ computer, a notebook computer, a tablet computer, a server computer, a handheld computer, a handheld device, an internet of things (IoT) device, a sensor device, a PDA device, a handheld PDA device, an on-board device, an off-board device, a hybrid device (e.g., combining cellular phone functionalities with PDA device functionalities), a consumer device, a vehicular device, a non-vehicular device, a mobile or portable device, a non-mobile or non-portable device, a mobile phone, a cellular telephone, a PCS device, a PDA device which incorporates a wireless communication device, a mobile or portable GPS device, a DVB device, a relatively small computing device, a non-desktop computer, a “carry small live large” (CSLL) device, an ultra mobile device (UMD), an ultra mobile PC (UMPC), a mobile Internet device (MID), an “origami” device or computing device, a device that supports dynamically composable computing (DCC), a context-aware device, a video device, an audio device, an A/V device, a set-top-box (STB), a blu-ray disc (BD) player, a BD recorder, a digital video disc (DVD) player, a high definition (HD) DVD player, a DVD recorder, a HD DVD recorder, a personal video recorder (PVR), a broadcast HD receiver, a video source, an audio source, a video sink, an audio sink, a stereo tuner, a broadcast radio receiver, a flat panel display, a personal media player (PMP), a digital video camera (DVC), a digital audio player, a speaker, an audio receiver, an audio amplifier, a gaming device, a data source, a data sink, a digital still camera (DSC), a media player, a smartphone, a television, a music player, or the like. Other devices, including smart devices such as lamps, climate control, car components, household components, appliances, etc. may also be included in this list. 
     As used herein, the term “Internet of Things (IoT) device” is used to refer to any object (e.g., an appliance, a sensor, etc.) that has an addressable interface (e.g., an Internet protocol (IP) address, a Bluetooth identifier (ID), a near-field communication (NFC) ID, etc.) and can transmit information to one or more other devices over a wired or wireless connection. An IoT device may have a passive communication interface, such as a quick response (QR) code, a radio-frequency identification (RFID) tag, an NFC tag, or the like, or an active communication interface, such as a modem, a transceiver, a transmitter-receiver, or the like. An IoT device can have a particular set of attributes (e.g., a device state or status, such as whether the IoT device is on or off, open or closed, idle or active, available for task execution or busy, and so on, a cooling or heating function, an environmental monitoring or recording function, a light-emitting function, a sound-emitting function, etc.) that can be embedded in and/or controlled/monitored by a central processing unit (CPU), microprocessor, ASIC, or the like, and configured for connection to an IoT network such as a local ad-hoc network or the Internet. For example, IoT devices may include, but are not limited to, refrigerators, toasters, ovens, microwaves, freezers, dishwashers, dishes, hand tools, clothes washers, clothes dryers, furnaces, air conditioners, thermostats, televisions, light fixtures, vacuum cleaners, sprinklers, electricity meters, gas meters, etc., so long as the devices are equipped with an addressable communications interface for communicating with the IoT network. IoT devices may also include cell phones, desktop computers, laptop computers, tablet computers, personal digital assistants (PDAs), etc. Accordingly, the IoT network may be comprised of a combination of “legacy” Internet-accessible devices (e.g., laptop or desktop computers, cell phones, etc.) in addition to devices that do not typically have Internet-connectivity (e.g., dishwashers, etc.). 
     The user device(s)  120  and/or AP(s)  102  may also include mesh stations in, for example, a mesh network, in accordance with one or more IEEE 802.11 standards and/or 3GPP standards. 
     Any of the user device(s)  120  (e.g., user devices  124 ,  126 ,  128 ), and AP(s)  102  may be configured to communicate with each other via one or more communications networks  130  and/or  135  wirelessly or wired. The user device(s)  120  may also communicate peer-to-peer or directly with each other with or without the AP(s)  102 . Any of the communications networks  130  and/or  135  may include, but not limited to, any one of a combination of different types of suitable communications networks such as, for example, broadcasting networks, cable networks, public networks (e.g., the Internet), private networks, wireless networks, cellular networks, or any other suitable private and/or public networks. Further, any of the communications networks  130  and/or  135  may have any suitable communication range associated therewith and may include, for example, global networks (e.g., the Internet), metropolitan area networks (MANs), wide area networks (WANs), local area networks (LANs), or personal area networks (PANs). In addition, any of the communications networks  130  and/or  135  may include any type of medium over which network traffic may be carried including, but not limited to, coaxial cable, twisted-pair wire, optical fiber, a hybrid fiber coaxial (HFC) medium, microwave terrestrial transceivers, radio frequency communication mediums, white space communication mediums, ultra-high frequency communication mediums, satellite communication mediums, or any combination thereof. 
     Any of the user device(s)  120  (e.g., user devices  124 ,  126 ,  128 ) and AP(s)  102  may include one or more communications antennas. The one or more communications antennas may be any suitable type of antennas corresponding to the communications protocols used by the user device(s)  120  (e.g., user devices  124 ,  126  and  128 ), and AP(s)  102 . Some non-limiting examples of suitable communications antennas include Wi-Fi antennas, Institute of Electrical and Electronics Engineers (IEEE) 802.11 family of standards compatible antennas, directional antennas, non-directional antennas, dipole antennas, folded dipole antennas, patch antennas, multiple-input multiple-output (MIMO) antennas, omnidirectional antennas, quasi-omnidirectional antennas, or the like. The one or more communications antennas may be communicatively coupled to a radio component to transmit and/or receive signals, such as communications signals to and/or from the user devices  120  and/or AP(s)  102 . 
     Any of the user device(s)  120  (e.g., user devices  124 ,  126 ,  128 ), and AP(s)  102  may be configured to perform directional transmission and/or directional reception in conjunction with wirelessly communicating in a wireless network. Any of the user device(s)  120  (e.g., user devices  124 ,  126 ,  128 ), and AP(s)  102  may be configured to perform such directional transmission and/or reception using a set of multiple antenna arrays (e.g., DMG antenna arrays or the like). Each of the multiple antenna arrays may be used for transmission and/or reception in a particular respective direction or range of directions. Any of the user device(s)  120  (e.g., user devices  124 ,  126 ,  128 ), and AP(s)  102  may be configured to perform any given directional transmission towards one or more defined transmit sectors. Any of the user device(s)  120  (e.g., user devices  124 ,  126 ,  128 ), and AP(s)  102  may be configured to perform any given directional reception from one or more defined receive sectors. 
     MIMO beamforming in a wireless network may be accomplished using RF beamforming and/or digital beamforming. In some embodiments, in performing a given MIMO transmission, user devices  120  and/or AP(s)  102  may be configured to use all or a subset of its one or more communications antennas to perform MIMO beamforming. 
     Any of the user devices  120  (e.g., user devices  124 ,  126 ,  128 ), and AP(s)  102  may include any suitable radio and/or transceiver for transmitting and/or receiving radio frequency (RF) signals in the bandwidth and/or channels corresponding to the communications protocols utilized by any of the user device(s)  120  and AP(s)  102  to communicate with each other. The radio components may include hardware and/or software to modulate and/or demodulate communications signals according to pre-established transmission protocols. The radio components may further have hardware and/or software instructions to communicate via one or more Wi-Fi and/or Wi-Fi direct protocols, as standardized by the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards. In certain example embodiments, the radio component, in cooperation with the communications antennas, may be configured to communicate via 2.4 GHz channels (e.g. 802.11b, 802.11g, 802.11n, 802.11ax), 5 GHz channels (e.g. 802.11n, 802.11ac, 802.11ax, 802.11be, etc.), 6 GHz channels (e.g., 802.11ax, 802.11be, etc.), or 60 GHZ channels (e.g. 802.11ad, 802.11ay). 800 MHz channels (e.g. 802.11ah). The communications antennas may operate at 28 GHz and 40 GHz. It should be understood that this list of communication channels in accordance with certain 802.11 standards is only a partial list and that other 802.11 standards may be used (e.g., Next Generation Wi-Fi, or other standards). In some embodiments, non-Wi-Fi protocols may be used for communications between devices, such as Bluetooth, dedicated short-range communication (DSRC), Ultra-High Frequency (UHF) (e.g. IEEE 802.11af, IEEE 802.22), white band frequency (e.g., white spaces), or other packetized radio communications. The radio component may include any known receiver and baseband suitable for communicating via the communications protocols. The radio component may further include a low noise amplifier (LNA), additional signal amplifiers, an analog-to-digital (A/D) converter, one or more buffers, and digital baseband. 
     In one embodiment, and with reference to  FIG.  1   , a user device  120  may be in communication with one or more APs  102 . For example, one or more APs  102  may implement a TWT for MLO  142  with one or more user devices  120 . The one or more APs  102  may be multi-link devices (MLDs) and the one or more user device  120  may be non-AP MLDs. Each of the one or more APs  102  may comprise a plurality of individual APs (e.g., AP1, AP2, . . . , APn, where n is an integer) and each of the one or more user devices  120  may comprise a plurality of individual STAs (e.g., STA1, STA2, . . . , STAn). The AP MLDs and the non-AP MLDs may set up one or more links (e.g., Link1, Link2, . . . , Linkn) between each of the individual APs and STAs. It is understood that the above descriptions are for purposes of illustration and are not meant to be limiting. 
     In one or more embodiments, a TWT for MLO system may facilitate modifying the TWT element in order to provide an indication that specific rules will have to be followed by the 2 peers (initiator of the TWT setup frame containing the TWT element and responder of the TWT setup frame containing the TWT element): 
     In one or more embodiments, a TWT for MLO system may define a new field called “unavailability”, for instance, that new field may be in the Traffic Info Control field (using a reserved bit) that is set to 1 to indicate that during the TWT SP, the initiator STA will be unavailable (busy for operation on another link) and set to 0 otherwise. 
     If set to 1, specific rules are defined: 
     The initiator and the responder shall end TxOP before the start of the TWT SP 
     The responder shall not transmit a frame to the responder or trigger a transmission from the initiator during the TWT SP. 
     This field can be set when sent by an initiator STA in an unsolicited TWT response frame and the rules start applying after successful reception. 
     There could be a restriction that this can only be sent from a STA and not from an AP 
     This field can be used for instance if the STA (operating on link 1) is part of a non-AP MLD operating with eMLSR and has scheduled an rTWT during the same TWT SP on the other link (link 2) and if it wants to make sure that the AP will not transmit to the STA on link 1 during the rTWT on link 2. It will then send this unsolicited TWT response frame with this Unavailability bit set to 1 on link 1 so that it overlaps with the rTWT on link 2. As there is an eMLSR transition delay in order to transition from eMLSR TxOP to listen mode on all eMLSR links, the initiator STA can make sure that it will send the TWT element with that field set to 1 on link 1 for a TWT SP that will start eMLSR transition delay prior to the start time of the rTWT SP on link 2 (to make sure that the STA on link 2 will be fully available at the start of the rTWT SP on link 2, even if the AP on link1 ends its TxOP (with the STA as TxOP responder) right for the start of the TWT SP with Unavailability bit set to 1 on link1. Alternatively, a field called eMLSR transition delay may be added in the TWT setup response frame in order to indicate that the rules to end the TxOP shall start the eMLSR transition delay before the start of the TWT SP. 
     In one or more embodiments, a TWT for MLO system may define a new field, for instance, called “NSTR restrictions”, that indicates that additional restrictions will apply to the initiator STA during the TWT SP 
     It is set to 1 to indicate that the STA will have NSTR restrictions during the TWT SP. 
     If this bit is set to 1, the STA will set the LinkID bitmap field to indicate the linkID of the link on which the initiator STA of the non-AP MLD will operate during the TWT SP. Alternatively, a TWT for the MLO system may define a new field or add a new field/element in the TWT response frame to include the information of which link the STA will have NSTR constraints with. 
     It is understood that the above descriptions are for purposes of illustration and are not meant to be limiting. 
       FIG.  2    illustrates a flow diagram of illustrative process  200  for a TWT for MLO system, in accordance with one or more example embodiments of the present disclosure. 
     At block  202 , a device (e.g., the user device(s)  120  and/or the AP  102  of  FIG.  1    and/or the TWT for MLO device  419  of  FIG.  4   ) may establish a first communication link between a first non-AP STA of a non-AP MLD and a first AP of the AP MLD. 
     At block  204 , the device may establish a second communication link between a second non-AP STA of the non-AP MLD and a second AP of the AP MLD. 
     At block  206 , the device may cause to send on the second communication link a frame from the second non-AP STA to the second AP, wherein the frame comprises availability information associated with the second non-AP STA. 
     It is understood that the above descriptions are for purposes of illustration and are not meant to be limiting. 
       FIG.  3    shows a functional diagram of an exemplary communication station  300 , in accordance with one or more example embodiments of the present disclosure. In one embodiment,  FIG.  3    illustrates a functional block diagram of a communication station that may be suitable for use as an AP  102  ( FIG.  1   ) or a user device  120  ( FIG.  1   ) in accordance with some embodiments. The communication station  300  may also be suitable for use as a handheld device, a mobile device, a cellular telephone, a smartphone, a tablet, a netbook, a wireless terminal, a laptop computer, a wearable computer device, a femtocell, a high data rate (HDR) subscriber station, an access point, an access terminal, or other personal communication system (PCS) device. 
     The communication station  300  may include communications circuitry  302  and a transceiver  310  for transmitting and receiving signals to and from other communication stations using one or more antennas  301 . The communications circuitry  302  may include circuitry that can operate the physical layer (PHY) communications and/or medium access control (MAC) communications for controlling access to the wireless medium, and/or any other communications layers for transmitting and receiving signals. The communication station  300  may also include processing circuitry  306  and memory  308  arranged to perform the operations described herein. In some embodiments, the communications circuitry  302  and the processing circuitry  306  may be configured to perform operations detailed in the above figures, diagrams, and flows. 
     In accordance with some embodiments, the communications circuitry  302  may be arranged to contend for a wireless medium and configure frames or packets for communicating over the wireless medium. The communications circuitry  302  may be arranged to transmit and receive signals. The communications circuitry  302  may also include circuitry for modulation/demodulation, upconversion/downconversion, filtering, amplification, etc. In some embodiments, the processing circuitry  306  of the communication station  300  may include one or more processors. In other embodiments, two or more antennas  301  may be coupled to the communications circuitry  302  arranged for sending and receiving signals. The memory  308  may store information for configuring the processing circuitry  306  to perform operations for configuring and transmitting message frames and performing the various operations described herein. The memory  308  may include any type of memory, including non-transitory memory, for storing information in a form readable by a machine (e.g., a computer). For example, the memory  308  may include a computer-readable storage device, read-only memory (ROM), random-access memory (RAM), magnetic disk storage media, optical storage media, flash-memory devices and other storage devices and media. 
     In some embodiments, the communication station  300  may be part of a portable wireless communication device, such as a personal digital assistant (PDA), a laptop or portable computer with wireless communication capability, a web tablet, a wireless telephone, a smartphone, a wireless headset, a pager, an instant messaging device, a digital camera, an access point, a television, a medical device (e.g., a heart rate monitor, a blood pressure monitor, etc.), a wearable computer device, or another device that may receive and/or transmit information wirelessly. 
     In some embodiments, the communication station  300  may include one or more antennas  301 . The antennas  301  may include one or more directional or omnidirectional antennas, including, for example, dipole antennas, monopole antennas, patch antennas, loop antennas, microstrip antennas, or other types of antennas suitable for transmission of RF signals. In some embodiments, instead of two or more antennas, a single antenna with multiple apertures may be used. In these embodiments, each aperture may be considered a separate antenna. In some multiple-input multiple-output (MIMO) embodiments, the antennas may be effectively separated for spatial diversity and the different channel characteristics that may result between each of the antennas and the antennas of a transmitting station. 
     In some embodiments, the communication station  300  may include one or more of a keyboard, a display, a non-volatile memory port, multiple antennas, a graphics processor, an application processor, speakers, and other mobile device elements. The display may be an LCD screen including a touch screen. 
     Although the communication station  300  is illustrated as having several separate functional elements, two or more of the functional elements may be combined and may be implemented by combinations of software-configured elements, such as processing elements including digital signal processors (DSPs), and/or other hardware elements. For example, some elements may include one or more microprocessors, DSPs, field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), radio-frequency integrated circuits (RFICs) and combinations of various hardware and logic circuitry for performing at least the functions described herein. In some embodiments, the functional elements of the communication station  300  may refer to one or more processes operating on one or more processing elements. 
     Certain embodiments may be implemented in one or a combination of hardware, firmware, and software. Other embodiments may also be implemented as instructions stored on a computer-readable storage device, which may be read and executed by at least one processor to perform the operations described herein. A computer-readable storage device may include any non-transitory memory mechanism for storing information in a form readable by a machine (e.g., a computer). For example, a computer-readable storage device may include read-only memory (ROM), random-access memory (RAM), magnetic disk storage media, optical storage media, flash-memory devices, and other storage devices and media. In some embodiments, the communication station  300  may include one or more processors and may be configured with instructions stored on a computer-readable storage device. 
       FIG.  4    illustrates a block diagram of an example of a machine  400  or system upon which any one or more of the techniques (e.g., methodologies) discussed herein may be performed. In other embodiments, the machine  400  may operate as a standalone device or may be connected (e.g., networked) to other machines. In a networked deployment, the machine  400  may operate in the capacity of a server machine, a client machine, or both in server-client network environments. In an example, the machine  400  may act as a peer machine in peer-to-peer (P2P) (or other distributed) network environments. The machine  400  may be a personal computer (PC), a tablet PC, a set-top box (STB), a personal digital assistant (PDA), a mobile telephone, a wearable computer device, a web appliance, a network router, a switch or bridge, or any machine capable of executing instructions (sequential or otherwise) that specify actions to be taken by that machine, such as a base station. Further, while only a single machine is illustrated, the term “machine” shall also be taken to include any collection of machines that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein, such as cloud computing, software as a service (SaaS), or other computer cluster configurations. 
     Examples, as described herein, may include or may operate on logic or a number of components, modules, or mechanisms. Modules are tangible entities (e.g., hardware) capable of performing specified operations when operating. A module includes hardware. In an example, the hardware may be specifically configured to carry out a specific operation (e.g., hardwired). In another example, the hardware may include configurable execution units (e.g., transistors, circuits, etc.) and a computer readable medium containing instructions where the instructions configure the execution units to carry out a specific operation when in operation. The configuring may occur under the direction of the executions units or a loading mechanism. Accordingly, the execution units are communicatively coupled to the computer-readable medium when the device is operating. In this example, the execution units may be a member of more than one module. For example, under operation, the execution units may be configured by a first set of instructions to implement a first module at one point in time and reconfigured by a second set of instructions to implement a second module at a second point in time. 
     The machine (e.g., computer system)  400  may include a hardware processor  402  (e.g., a central processing unit (CPU), a graphics processing unit (GPU), a hardware processor core, or any combination thereof), a main memory  404  and a static memory  406 , some or all of which may communicate with each other via an interlink (e.g., bus)  408 . The machine  400  may further include a power management device  432 , a graphics display device  410 , an alphanumeric input device  412  (e.g., a keyboard), and a user interface (UI) navigation device  414  (e.g., a mouse). In an example, the graphics display device  410 , alphanumeric input device  412 , and UI navigation device  414  may be a touch screen display. The machine  400  may additionally include a storage device (i.e., drive unit)  416 , a signal generation device  418  (e.g., a speaker), a TWT for MLO device  419 , a network interface device/transceiver  420  coupled to antenna(s)  430 , and one or more sensors  428 , such as a global positioning system (GPS) sensor, a compass, an accelerometer, or other sensor. The machine  400  may include an output controller  434 , such as a serial (e.g., universal serial bus (USB), parallel, or other wired or wireless (e.g., infrared (IR), near field communication (NFC), etc.) connection to communicate with or control one or more peripheral devices (e.g., a printer, a card reader, etc.). The operations in accordance with one or more example embodiments of the present disclosure may be carried out by a baseband processor. The baseband processor may be configured to generate corresponding baseband signals. The baseband processor may further include physical layer (PHY) and medium access control layer (MAC) circuitry, and may further interface with the hardware processor  402  for generation and processing of the baseband signals and for controlling operations of the main memory  404 , the storage device  416 , and/or the TWT for MLO device  419 . The baseband processor may be provided on a single radio card, a single chip, or an integrated circuit (IC). 
     The storage device  416  may include a machine readable medium  422  on which is stored one or more sets of data structures or instructions  424  (e.g., software) embodying or utilized by any one or more of the techniques or functions described herein. The instructions  424  may also reside, completely or at least partially, within the main memory  404 , within the static memory  406 , or within the hardware processor  402  during execution thereof by the machine  400 . In an example, one or any combination of the hardware processor  402 , the main memory  404 , the static memory  406 , or the storage device  416  may constitute machine-readable media. 
     The TWT for MLO device  419  may carry out or perform any of the operations and processes (e.g., process  200 ) described and shown above. 
     It is understood that the above are only a subset of what the TWT for MLO device  419  may be configured to perform and that other functions included throughout this disclosure may also be performed by the TWT for MLO device  419 . 
     While the machine-readable medium  422  is illustrated as a single medium, the term “machine-readable medium” may include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) configured to store the one or more instructions  424 . 
     Various embodiments may be implemented fully or partially in software and/or firmware. This software and/or firmware may take the form of instructions contained in or on a non-transitory computer-readable storage medium. Those instructions may then be read and executed by one or more processors to enable performance of the operations described herein. The instructions may be in any suitable form, such as but not limited to source code, compiled code, interpreted code, executable code, static code, dynamic code, and the like. Such a computer-readable medium may include any tangible non-transitory medium for storing information in a form readable by one or more computers, such as but not limited to read only memory (ROM); 
     random access memory (RAM); magnetic disk storage media; optical storage media; a flash memory, etc. 
     The term “machine-readable medium” may include any medium that is capable of storing, encoding, or carrying instructions for execution by the machine  400  and that cause the machine  400  to perform any one or more of the techniques of the present disclosure, or that is capable of storing, encoding, or carrying data structures used by or associated with such instructions. Non-limiting machine-readable medium examples may include solid-state memories and optical and magnetic media. In an example, a massed machine-readable medium includes a machine-readable medium with a plurality of particles having resting mass. Specific examples of massed machine-readable media may include non-volatile memory, such as semiconductor memory devices (e.g., electrically programmable read-only memory (EPROM), or electrically erasable programmable read-only memory (EEPROM)) and flash memory devices; magnetic disks, such as internal hard disks and removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. 
     The instructions  424  may further be transmitted or received over a communications network  426  using a transmission medium via the network interface device/transceiver  420  utilizing any one of a number of transfer protocols (e.g., frame relay, internet protocol (IP), transmission control protocol (TCP), user datagram protocol (UDP), hypertext transfer protocol (HTTP), etc.). Example communications networks may include a local area network (LAN), a wide area network (WAN), a packet data network (e.g., the Internet), mobile telephone networks (e.g., cellular networks), plain old telephone (POTS) networks, wireless data networks (e.g., Institute of Electrical and Electronics Engineers (IEEE) 802.11 family of standards known as Wi-Fi®, IEEE 802.16 family of standards known as WiMax®), IEEE 802.15.4 family of standards, and peer-to-peer (P2P) networks, among others. In an example, the network interface device/transceiver  420  may include one or more physical jacks (e.g., Ethernet, coaxial, or phone jacks) or one or more antennas to connect to the communications network  426 . In an example, the network interface device/transceiver  420  may include a plurality of antennas to wirelessly communicate using at least one of single-input multiple-output (SIMO), multiple-input multiple-output (MIMO), or multiple-input single-output (MISO) techniques. The term “transmission medium” shall be taken to include any intangible medium that is capable of storing, encoding, or carrying instructions for execution by the machine  400  and includes digital or analog communications signals or other intangible media to facilitate communication of such software. 
     The operations and processes described and shown above may be carried out or performed in any suitable order as desired in various implementations. Additionally, in certain implementations, at least a portion of the operations may be carried out in parallel. Furthermore, in certain implementations, less than or more than the operations described may be performed. 
       FIG.  5    is a block diagram of a radio architecture  105 A,  105 B in accordance with some embodiments that may be implemented in any one of the example APs  102  and/or the example STAs  120  of  FIG.  1   . Radio architecture  105 A,  105 B may include radio front-end module (FEM) circuitry  504   a - b , radio IC circuitry  506   a - b  and baseband processing circuitry  508   a - b . Radio architecture  105 A,  105 B as shown includes both Wireless Local Area Network (WLAN) functionality and Bluetooth (BT) functionality although embodiments are not so limited. In this disclosure, “WLAN” and “Wi-Fi” are used interchangeably. 
     FEM circuitry  504   a - b  may include a WLAN or Wi-Fi FEM circuitry  504   a  and a Bluetooth (BT) FEM circuitry  504   b . The WLAN FEM circuitry  504   a  may include a receive signal path comprising circuitry configured to operate on WLAN RF signals received from one or more antennas  501 , to amplify the received signals and to provide the amplified versions of the received signals to the WLAN radio IC circuitry  506   a  for further processing. The BT FEM circuitry  504   b  may include a receive signal path which may include circuitry configured to operate on BT RF signals received from one or more antennas  501 , to amplify the received signals and to provide the amplified versions of the received signals to the BT radio IC circuitry  506   b  for further processing. FEM circuitry  504   a  may also include a transmit signal path which may include circuitry configured to amplify WLAN signals provided by the radio IC circuitry  506   a  for wireless transmission by one or more of the antennas  501 . In addition, FEM circuitry  504   b  may also include a transmit signal path which may include circuitry configured to amplify BT signals provided by the radio IC circuitry  506   b  for wireless transmission by the one or more antennas. In the embodiment of  FIG.  5   , although FEM  504   a  and FEM  504   b  are shown as being distinct from one another, embodiments are not so limited, and include within their scope the use of an FEM (not shown) that includes a transmit path and/or a receive path for both WLAN and BT signals, or the use of one or more FEM circuitries where at least some of the FEM circuitries share transmit and/or receive signal paths for both WLAN and BT signals. 
     Radio IC circuitry  506   a - b  as shown may include WLAN radio IC circuitry  506   a  and BT radio IC circuitry  506   b . The WLAN radio IC circuitry  506   a  may include a receive signal path which may include circuitry to down-convert WLAN RF signals received from the FEM circuitry  504   a  and provide baseband signals to WLAN baseband processing circuitry  508   a . BT radio IC circuitry  506   b  may in turn include a receive signal path which may include circuitry to down-convert BT RF signals received from the FEM circuitry  504   b  and provide baseband signals to BT baseband processing circuitry  508   b . WLAN radio IC circuitry  506   a  may also include a transmit signal path which may include circuitry to up-convert WLAN baseband signals provided by the WLAN baseband processing circuitry  508   a  and provide WLAN RF output signals to the FEM circuitry  504   a  for subsequent wireless transmission by the one or more antennas  501 . BT radio IC circuitry  506   b  may also include a transmit signal path which may include circuitry to up-convert BT baseband signals provided by the BT baseband processing circuitry  508   b  and provide BT RF output signals to the FEM circuitry  504   b  for subsequent wireless transmission by the one or more antennas  501 . In the embodiment of  FIG.  5   , although radio IC circuitries  506   a  and  506   b  are shown as being distinct from one another, embodiments are not so limited, and include within their scope the use of a radio IC circuitry (not shown) that includes a transmit signal path and/or a receive signal path for both WLAN and BT signals, or the use of one or more radio IC circuitries where at least some of the radio IC circuitries share transmit and/or receive signal paths for both WLAN and BT signals. 
     Baseband processing circuitry  508   a - b  may include a WLAN baseband processing circuitry  508   a  and a BT baseband processing circuitry  508   b . The WLAN baseband processing circuitry  508   a  may include a memory, such as, for example, a set of RAM arrays in a Fast Fourier Transform or Inverse Fast Fourier Transform block (not shown) of the WLAN baseband processing circuitry  508   a . Each of the WLAN baseband circuitry  508   a  and the BT baseband circuitry  508   b  may further include one or more processors and control logic to process the signals received from the corresponding WLAN or BT receive signal path of the radio IC circuitry  506   a - b , and to also generate corresponding WLAN or BT baseband signals for the transmit signal path of the radio IC circuitry  506   a - b . Each of the baseband processing circuitries  508   a  and  508   b  may further include physical layer (PHY) and medium access control layer (MAC) circuitry, and may further interface with a device for generation and processing of the baseband signals and for controlling operations of the radio IC circuitry  506   a - b.    
     Referring still to  FIG.  5   , according to the shown embodiment, WLAN-BT coexistence circuitry  513  may include logic providing an interface between the WLAN baseband circuitry  508   a  and the BT baseband circuitry  508   b  to enable use cases requiring WLAN and BT coexistence. In addition, a switch  503  may be provided between the WLAN FEM circuitry  504   a  and the BT FEM circuitry  504   b  to allow switching between the WLAN and BT radios according to application needs. In addition, although the antennas  501  are depicted as being respectively connected to the WLAN FEM circuitry  504   a  and the BT FEM circuitry  504   b , embodiments include within their scope the sharing of one or more antennas as between the WLAN and BT FEMs, or the provision of more than one antenna connected to each of FEM  504   a  or  504   b.    
     In some embodiments, the front-end module circuitry  504   a - b , the radio IC circuitry  506   a - b , and baseband processing circuitry  508   a - b  may be provided on a single radio card, such as wireless radio card  502 . In some other embodiments, the one or more antennas  501 , the FEM circuitry  504   a - b  and the radio IC circuitry  506   a - b  may be provided on a single radio card. In some other embodiments, the radio IC circuitry  506   a - b  and the baseband processing circuitry  508   a - b  may be provided on a single chip or integrated circuit (IC), such as IC  512 . 
     In some embodiments, the wireless radio card  502  may include a WLAN radio card and may be configured for Wi-Fi communications, although the scope of the embodiments is not limited in this respect. In some of these embodiments, the radio architecture  105 A,  105 B may be configured to receive and transmit orthogonal frequency division multiplexed (OFDM) or orthogonal frequency division multiple access (OFDMA) communication signals over a multicarrier communication channel. The OFDM or OFDMA signals may comprise a plurality of orthogonal subcarriers. 
     In some of these multicarrier embodiments, radio architecture  105 A,  105 B may be part of a Wi-Fi communication station (STA) such as a wireless access point (AP), a base station or a mobile device including a Wi-Fi device. In some of these embodiments, radio architecture  105 A,  105 B may be configured to transmit and receive signals in accordance with specific communication standards and/or protocols, such as any of the Institute of Electrical and Electronics Engineers (IEEE) standards including, 802.11n-2009, IEEE 802.11-2012, IEEE 802.11-2016, 802.11n-2009, 802.11ac, 802.11ah, 802.11ad, 802.11 ay and/or 802.11ax standards and/or proposed specifications for WLANs, although the scope of embodiments is not limited in this respect. Radio architecture  105 A,  105 B may also be suitable to transmit and/or receive communications in accordance with other techniques and standards. 
     In some embodiments, the radio architecture  105 A,  105 B may be configured for high-efficiency Wi-Fi (HEW) communications in accordance with the IEEE 802.11ax standard. In these embodiments, the radio architecture  105 A,  105 B may be configured to communicate in accordance with an OFDMA technique, although the scope of the embodiments is not limited in this respect. 
     In some other embodiments, the radio architecture  105 A,  105 B may be configured to transmit and receive signals transmitted using one or more other modulation techniques such as spread spectrum modulation (e.g., direct sequence code division multiple access (DS-CDMA) and/or frequency hopping code division multiple access (FH-CDMA)), time-division multiplexing (TDM) modulation, and/or frequency-division multiplexing (FDM) modulation, although the scope of the embodiments is not limited in this respect. 
     In some embodiments, as further shown in  FIG.  6   , the BT baseband circuitry  508   b  may be compliant with a Bluetooth (BT) connectivity standard such as Bluetooth, Bluetooth 8.0 or Bluetooth 6.0, or any other iteration of the Bluetooth Standard. 
     In some embodiments, the radio architecture  105 A,  105 B may include other radio cards, such as a cellular radio card configured for cellular (e.g., 5GPP such as LTE, LTE-Advanced or 7G communications). 
     In some IEEE 802.11 embodiments, the radio architecture  105 A,  105 B may be configured for communication over various channel bandwidths including bandwidths having center frequencies of about 900 MHz, 2.4 GHz, 5 GHz, and bandwidths of about 2 MHz, 4 MHz, 5 MHz, 5.5 MHz, 6 MHz, 8 MHz, 10 MHz, 20 MHz, 40 MHz, 80 MHz (with contiguous bandwidths) or 80+80 MHz (160 MHz) (with non-contiguous bandwidths). In some embodiments, a 920 MHz channel bandwidth may be used. The scope of the embodiments is not limited with respect to the above center frequencies however. 
       FIG.  6    illustrates WLAN FEM circuitry  504   a  in accordance with some embodiments. Although the example of  FIG.  6    is described in conjunction with the WLAN FEM circuitry  504   a , the example of  FIG.  6    may be described in conjunction with the example BT FEM circuitry  504   b  ( FIG.  5   ), although other circuitry configurations may also be suitable. 
     In some embodiments, the FEM circuitry  504   a  may include a TX/RX switch  602  to switch between transmit mode and receive mode operation. The FEM circuitry  504   a  may include a receive signal path and a transmit signal path. The receive signal path of the FEM circuitry  504   a  may include a low-noise amplifier (LNA)  606  to amplify received RF signals  603  and provide the amplified received RF signals  607  as an output (e.g., to the radio IC circuitry  506   a - b  ( FIG.  5   )). The transmit signal path of the circuitry  504   a  may include a power amplifier (PA) to amplify input RF signals  609  (e.g., provided by the radio IC circuitry  506   a - b ), and one or more filters  612 , such as band-pass filters (BPFs), low-pass filters (LPFs) or other types of filters, to generate RF signals  615  for subsequent transmission (e.g., by one or more of the antennas  501  ( FIG.  5   )) via an example duplexer  614 . 
     In some dual-mode embodiments for Wi-Fi communication, the FEM circuitry  504   a  may be configured to operate in either the 2.4 GHz frequency spectrum or the 5 GHz frequency spectrum. In these embodiments, the receive signal path of the FEM circuitry  504   a  may include a receive signal path duplexer  604  to separate the signals from each spectrum as well as provide a separate LNA  606  for each spectrum as shown. In these embodiments, the transmit signal path of the FEM circuitry  504   a  may also include a power amplifier  610  and a filter  612 , such as a BPF, an LPF or another type of filter for each frequency spectrum and a transmit signal path duplexer  604  to provide the signals of one of the different spectrums onto a single transmit path for subsequent transmission by the one or more of the antennas  501  ( FIG.  5   ). In some embodiments, BT communications may utilize the 2.4 GHz signal paths and may utilize the same FEM circuitry  504   a  as the one used for WLAN communications. 
       FIG.  7    illustrates radio IC circuitry  506   a  in accordance with some embodiments. The radio IC circuitry  506   a  is one example of circuitry that may be suitable for use as the WLAN or BT radio IC circuitry  506   a / 506   b  ( FIG.  5   ), although other circuitry configurations may also be suitable. Alternatively, the example of  FIG.  7    may be described in conjunction with the example BT radio IC circuitry  506   b.    
     In some embodiments, the radio IC circuitry  506   a  may include a receive signal path and a transmit signal path. The receive signal path of the radio IC circuitry  506   a  may include at least mixer circuitry  702 , such as, for example, down-conversion mixer circuitry, amplifier circuitry  706  and filter circuitry  708 . The transmit signal path of the radio IC circuitry  506   a  may include at least filter circuitry  712  and mixer circuitry  714 , such as, for example, up-conversion mixer circuitry. Radio IC circuitry  506   a  may also include synthesizer circuitry  704  for synthesizing a frequency  705  for use by the mixer circuitry  702  and the mixer circuitry  714 . The mixer circuitry  702  and/or  714  may each, according to some embodiments, be configured to provide direct conversion functionality. The latter type of circuitry presents a much simpler architecture as compared with standard super-heterodyne mixer circuitries, and any flicker noise brought about by the same may be alleviated for example through the use of OFDM modulation.  FIG.  7    illustrates only a simplified version of a radio IC circuitry, and may include, although not shown, embodiments where each of the depicted circuitries may include more than one component. For instance, mixer circuitry  714  may each include one or more mixers, and filter circuitries  708  and/or  712  may each include one or more filters, such as one or more BPFs and/or LPFs according to application needs. For example, when mixer circuitries are of the direct-conversion type, they may each include two or more mixers. 
     In some embodiments, mixer circuitry  702  may be configured to down-convert RF signals  607  received from the FEM circuitry  504   a - b  ( FIG.  5   ) based on the synthesized frequency  705  provided by synthesizer circuitry  704 . The amplifier circuitry  706  may be configured to amplify the down-converted signals and the filter circuitry  708  may include an LPF configured to remove unwanted signals from the down-converted signals to generate output baseband signals  707 . Output baseband signals  707  may be provided to the baseband processing circuitry  508   a - b  ( FIG.  5   ) for further processing. In some embodiments, the output baseband signals  707  may be zero-frequency baseband signals, although this is not a requirement. In some embodiments, mixer circuitry  702  may comprise passive mixers, although the scope of the embodiments is not limited in this respect. 
     In some embodiments, the mixer circuitry  714  may be configured to up-convert input baseband signals  711  based on the synthesized frequency  705  provided by the synthesizer circuitry  704  to generate RF output signals  609  for the FEM circuitry  504   a - b . The baseband signals  711  may be provided by the baseband processing circuitry  508   a - b  and may be filtered by filter circuitry  712 . The filter circuitry  712  may include an LPF or a BPF, although the scope of the embodiments is not limited in this respect. 
     In some embodiments, the mixer circuitry  702  and the mixer circuitry  714  may each include two or more mixers and may be arranged for quadrature down-conversion and/or up-conversion respectively with the help of synthesizer  704 . In some embodiments, the mixer circuitry  702  and the mixer circuitry  714  may each include two or more mixers each configured for image rejection (e.g., Hartley image rejection). In some embodiments, the mixer circuitry  702  and the mixer circuitry  714  may be arranged for direct down-conversion and/or direct up-conversion, respectively. In some embodiments, the mixer circuitry  702  and the mixer circuitry  714  may be configured for super-heterodyne operation, although this is not a requirement. 
     Mixer circuitry  702  may comprise, according to one embodiment: quadrature passive mixers (e.g., for the in-phase (I) and quadrature phase (Q) paths). In such an embodiment, RF input signal  607  from  FIG.  7    may be down-converted to provide I and Q baseband output signals to be sent to the baseband processor. 
     Quadrature passive mixers may be driven by zero and ninety-degree time-varying LO switching signals provided by a quadrature circuitry which may be configured to receive a LO frequency (fLO) from a local oscillator or a synthesizer, such as LO frequency  705  of synthesizer  704  ( FIG.  7   ). In some embodiments, the LO frequency may be the carrier frequency, while in other embodiments, the LO frequency may be a fraction of the carrier frequency (e.g., one-half the carrier frequency, one-third the carrier frequency). In some embodiments, the zero and ninety-degree time-varying switching signals may be generated by the synthesizer, although the scope of the embodiments is not limited in this respect. 
     In some embodiments, the LO signals may differ in duty cycle (the percentage of one period in which the LO signal is high) and/or offset (the difference between start points of the period). In some embodiments, the LO signals may have an 85% duty cycle and an 80% offset. In some embodiments, each branch of the mixer circuitry (e.g., the in-phase (I) and quadrature phase (Q) path) may operate at an 80% duty cycle, which may result in a significant reduction is power consumption. 
     The RF input signal  607  ( FIG.  6   ) may comprise a balanced signal, although the scope of the embodiments is not limited in this respect. The I and Q baseband output signals may be provided to low-noise amplifier, such as amplifier circuitry  706  ( FIG.  7   ) or to filter circuitry  708  ( FIG.  7   ). 
     In some embodiments, the output baseband signals  707  and the input baseband signals  711  may be analog baseband signals, although the scope of the embodiments is not limited in this respect. In some alternate embodiments, the output baseband signals  707  and the input baseband signals  711  may be digital baseband signals. In these alternate embodiments, the radio IC circuitry may include analog-to-digital converter (ADC) and digital-to-analog converter (DAC) circuitry. 
     In some dual-mode embodiments, a separate radio IC circuitry may be provided for processing signals for each spectrum, or for other spectrums not mentioned here, although the scope of the embodiments is not limited in this respect. 
     In some embodiments, the synthesizer circuitry  704  may be a fractional-N synthesizer or a fractional N/N+1 synthesizer, although the scope of the embodiments is not limited in this respect as other types of frequency synthesizers may be suitable. For example, synthesizer circuitry  704  may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer comprising a phase-locked loop with a frequency divider. According to some embodiments, the synthesizer circuitry  704  may include digital synthesizer circuitry. An advantage of using a digital synthesizer circuitry is that, although it may still include some analog components, its footprint may be scaled down much more than the footprint of an analog synthesizer circuitry. In some embodiments, frequency input into synthesizer circuitry  704  may be provided by a voltage controlled oscillator (VCO), although that is not a requirement. A divider control input may further be provided by either the baseband processing circuitry  508   a - b  ( FIG.  5   ) depending on the desired output frequency  705 . In some embodiments, a divider control input (e.g., N) may be determined from a look-up table (e.g., within a Wi-Fi card) based on a channel number and a channel center frequency as determined or indicated by the example application processor  510 . The application processor  510  may include, or otherwise be connected to, one of the example secure signal converter  101  or the example received signal converter  103  (e.g., depending on which device the example radio architecture is implemented in). 
     In some embodiments, synthesizer circuitry  704  may be configured to generate a carrier frequency as the output frequency  705 , while in other embodiments, the output frequency  705  may be a fraction of the carrier frequency (e.g., one-half the carrier frequency, one-third the carrier frequency). In some embodiments, the output frequency  705  may be a LO frequency (fLO). 
       FIG.  8    illustrates a functional block diagram of baseband processing circuitry  508   a  in accordance with some embodiments. The baseband processing circuitry  508   a  is one example of circuitry that may be suitable for use as the baseband processing circuitry  508   a  ( FIG.  5   ), although other circuitry configurations may also be suitable. Alternatively, the example of  FIG.  7    may be used to implement the example BT baseband processing circuitry  508   b  of  FIG.  5   . 
     The baseband processing circuitry  508   a  may include a receive baseband processor (RX BBP)  802  for processing receive baseband signals  709  provided by the radio IC circuitry  506   a - b  ( FIG.  5   ) and a transmit baseband processor (TX BBP)  804  for generating transmit baseband signals  711  for the radio IC circuitry  506   a - b . The baseband processing circuitry  508   a  may also include control logic  806  for coordinating the operations of the baseband processing circuitry  508   a.    
     In some embodiments (e.g., when analog baseband signals are exchanged between the baseband processing circuitry  508   a - b  and the radio IC circuitry  506   a - b ), the baseband processing circuitry  508   a  may include ADC  810  to convert analog baseband signals  809  received from the radio IC circuitry  506   a - b  to digital baseband signals for processing by the RX BBP  802 . In these embodiments, the baseband processing circuitry  508   a  may also include DAC  812  to convert digital baseband signals from the TX BBP  804  to analog baseband signals  811 . 
     In some embodiments that communicate OFDM signals or OFDMA signals, such as through baseband processor  508   a , the transmit baseband processor  804  may be configured to generate OFDM or OFDMA signals as appropriate for transmission by performing an inverse fast Fourier transform (IFFT). The receive baseband processor  802  may be configured to process received OFDM signals or OFDMA signals by performing an FFT. In some embodiments, the receive baseband processor  802  may be configured to detect the presence of an OFDM signal or OFDMA signal by performing an autocorrelation, to detect a preamble, such as a short preamble, and by performing a cross-correlation, to detect a long preamble. The preambles may be part of a predetermined frame structure for Wi-Fi communication. 
     Referring back to  FIG.  5   , in some embodiments, the antennas  501  ( FIG.  5   ) may each comprise one or more directional or omnidirectional antennas, including, for example, dipole antennas, monopole antennas, patch antennas, loop antennas, microstrip antennas or other types of antennas suitable for transmission of RF signals. In some multiple-input multiple-output (MIMO) embodiments, the antennas may be effectively separated to take advantage of spatial diversity and the different channel characteristics that may result. Antennas  501  may each include a set of phased-array antennas, although embodiments are not so limited. 
     Although the radio architecture  105 A,  105 B is illustrated as having several separate functional elements, one or more of the functional elements may be combined and may be implemented by combinations of software-configured elements, such as processing elements including digital signal processors (DSPs), and/or other hardware elements. For example, some elements may comprise one or more microprocessors, DSPs, field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), radio-frequency integrated circuits (RFICs) and combinations of various hardware and logic circuitry for performing at least the functions described herein. In some embodiments, the functional elements may refer to one or more processes operating on one or more processing elements. 
     The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. The terms “computing device,” “user device,” “communication station,” “station,” “handheld device,” “mobile device,” “wireless device” and “user equipment” (UE) as used herein refers to a wireless communication device such as a cellular telephone, a smartphone, a tablet, a netbook, a wireless terminal, a laptop computer, a femtocell, a high data rate (HDR) subscriber station, an access point, a printer, a point of sale device, an access terminal, or other personal communication system (PCS) device. The device may be either mobile or stationary. 
     As used within this document, the term “communicate” is intended to include transmitting, or receiving, or both transmitting and receiving. This may be particularly useful in claims when describing the organization of data that is being transmitted by one device and received by another, but only the functionality of one of those devices is required to infringe the claim. Similarly, the bidirectional exchange of data between two devices (both devices transmit and receive during the exchange) may be described as “communicating,” when only the functionality of one of those devices is being claimed. The term “communicating” as used herein with respect to a wireless communication signal includes transmitting the wireless communication signal and/or receiving the wireless communication signal. For example, a wireless communication unit, which is capable of communicating a wireless communication signal, may include a wireless transmitter to transmit the wireless communication signal to at least one other wireless communication unit, and/or a wireless communication receiver to receive the wireless communication signal from at least one other wireless communication unit. 
     As used herein, unless otherwise specified, the use of the ordinal adjectives “first,” “second,” “third,” etc., to describe a common object, merely indicates that different instances of like objects are being referred to and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking, or in any other manner. 
     The term “access point” (AP) as used herein may be a fixed station. An access point may also be referred to as an access node, a base station, an evolved node B (eNodeB), or some other similar terminology known in the art. An access terminal may also be called a mobile station, user equipment (UE), a wireless communication device, or some other similar terminology known in the art. Embodiments disclosed herein generally pertain to wireless networks. Some embodiments may relate to wireless networks that operate in accordance with one of the IEEE 802.11 standards. 
     Some embodiments may be used in conjunction with various devices and systems, for example, a personal computer (PC), a desktop computer, a mobile computer, a laptop computer, a notebook computer, a tablet computer, a server computer, a handheld computer, a handheld device, a personal digital assistant (PDA) device, a handheld PDA device, an on-board device, an off-board device, a hybrid device, a vehicular device, a non-vehicular device, a mobile or portable device, a consumer device, a non-mobile or non-portable device, a wireless communication station, a wireless communication device, a wireless access point (AP), a wired or wireless router, a wired or wireless modem, a video device, an audio device, an audio-video (A/V) device, a wired or wireless network, a wireless area network, a wireless video area network (WVAN), a local area network (LAN), a wireless LAN (WLAN), a personal area network (PAN), a wireless PAN (WPAN), and the like. 
     Some embodiments may be used in conjunction with one way and/or two-way radio communication systems, cellular radio-telephone communication systems, a mobile phone, a cellular telephone, a wireless telephone, a personal communication system (PCS) device, a PDA device which incorporates a wireless communication device, a mobile or portable global positioning system (GPS) device, a device which incorporates a GPS receiver or transceiver or chip, a device which incorporates an RFID element or chip, a multiple input multiple output (MIMO) transceiver or device, a single input multiple output (SIMO) transceiver or device, a multiple input single output (MISO) transceiver or device, a device having one or more internal antennas and/or external antennas, digital video broadcast (DVB) devices or systems, multi-standard radio devices or systems, a wired or wireless handheld device, e.g., a smartphone, a wireless application protocol (WAP) device, or the like. 
     Some embodiments may be used in conjunction with one or more types of wireless communication signals and/or systems following one or more wireless communication protocols, for example, radio frequency (RF), infrared (IR), frequency-division multiplexing (FDM), orthogonal FDM (OFDM), time-division multiplexing (TDM), time-division multiple access (TDMA), extended TDMA (E-TDMA), general packet radio service (GPRS), extended GPRS, code-division multiple access (CDMA), wideband CDMA (WCDMA), CDMA 2000, single-carrier CDMA, multi-carrier CDMA, multi-carrier modulation (MDM), discrete multi-tone (DMT), Bluetooth®, global positioning system (GPS), Wi-Fi, Wi-Max, ZigBee, ultra-wideband (UWB), global system for mobile communications (GSM), 2G, 2.5G, 3G, 3.5G, 4G, fifth generation (5G) mobile networks, 3GPP, long term evolution (LTE), LTE advanced, enhanced data rates for GSM Evolution (EDGE), or the like. Other embodiments may be used in various other devices, systems, and/or networks. 
     The following examples pertain to further embodiments. 
     Example 1 may include a device comprising processing circuitry coupled to storage, the processing circuitry configured to: establish a first communication link between a first non-AP STA of a non-AP MLD and a first AP of the AP MLD; establish a second communication link between a second non-AP STA of the non-AP MLD and a second AP of the AP MLD; cause to send on the second communication link a frame from the second non-AP STA to the second AP, wherein the frame comprises availability information associated with the second non-AP STA. 
     Example 2 may include the device of example 1 and/or some other example herein, wherein the availability information may be a bit set to 1 to indicate an unavailable status. 
     Example 3 may include the device of example 1 and/or some other example herein, wherein the availability information may be a bit set to 0 to indicate an available status. 
     Example 4 may include the device of example 1 and/or some other example herein, wherein the processing circuitry may be further configured to identify a response frame from the second AP, wherein the response frame indicates acceptance or denial of the availability information. 
     Example 5 may include the device of example 1 and/or some other example herein, wherein the non-AP MLD may be a non-simultaneous transmit receive (NSTR) device. 
     Example 6 may include the device of example 1 and/or some other example herein, wherein a restricted target wake time (rTWT) may be established on the first communication link. 
     Example 7 may include the device of example 6 and/or some other example herein, wherein an unavailability status of the second non-AP STA may be for a period of the rTWT. 
     Example 8 may include the device of example 7 and/or some other example herein, wherein the non-AP MLD may be an enhanced multilink single radio (eMLSR). 
     Example 9 may include the device of example 1 and/or some other example herein, further comprising a transceiver configured to transmit and receive wireless signals. 
     Example 10 may include the device of example 4 and/or some other example herein, further comprising an antenna coupled to the transceiver to cause to send the frame. 
     Example 11 may include a non-transitory computer-readable medium storing computer-executable instructions which when executed by one or more processors result in performing operations comprising: establishing a first communication link between a first non-AP STA of a non-AP MLD and a first AP of the AP MLD; establishing a second communication link between a second non-AP STA of the non-AP MLD and a second AP of the AP MLD; causing to send on the second communication link a frame from the second non-AP STA to the second AP, wherein the frame comprises availability information associated with the second non-AP STA. 
     Example 12 may include the non-transitory computer-readable medium of example 11 and/or some other example herein, wherein the availability information may be a bit set to 1 to indicate an unavailable status. 
     Example 13 may include the non-transitory computer-readable medium of example 11 and/or some other example herein, wherein the availability information may be a bit set to 0 to indicate an available status. 
     Example 14 may include the non-transitory computer-readable medium of example 11 and/or some other example herein, wherein the operations further comprise identifying a response frame from the second AP, wherein the response frame indicates acceptance or denial of the availability information. 
     Example 15 may include the non-transitory computer-readable medium of example 11 and/or some other example herein, wherein the non-AP MLD may be a non-simultaneous transmit receive (NSTR) device. 
     Example 16 may include the non-transitory computer-readable medium of example 11 and/or some other example herein, wherein a restricted target wake time (rTWT) may be established on the first communication link. 
     Example 17 may include the non-transitory computer-readable medium of example 16 and/or some other example herein, wherein an unavailability status of the second non-AP STA may be for a period of the rTWT. 
     Example 18 may include the non-transitory computer-readable medium of example 17 and/or some other example herein, wherein the non-AP MLD may be an enhanced multilink single radio (eMLSR). 
     Example 19 may include a method comprising: establishing, by one or more processors, a first communication link between a first non-AP STA of a non-AP MLD and a first AP of the AP MLD; establishing a second communication link between a second non-AP STA of the non-AP MLD and a second AP of the AP MLD; causing to send on the second communication link a frame from the second non-AP STA to the second AP, wherein the frame comprises availability information associated with the second non-AP STA. 
     Example 20 may include the method of example 19 and/or some other example herein, wherein the availability information may be a bit set to 1 to indicate an unavailable status. 
     Example 21 may include the method of example 19 and/or some other example herein, wherein the availability information may be a bit set to 0 to indicate an available status. 
     Example 22 may include the method of example 19 and/or some other example herein, further comprising identifying a response frame from the second AP, wherein the response frame indicates acceptance or denial of the availability information. 
     Example 23 may include the method of example 19 and/or some other example herein, wherein the non-AP MLD may be a non-simultaneous transmit receive (NSTR) device. 
     Example 24 may include the method of example 19 and/or some other example herein, wherein a restricted target wake time (rTWT) may be established on the first communication link. 
     Example 25 may include the method of example 24 and/or some other example herein, wherein an unavailability status of the second non-AP STA may be for a period of the rTWT. 
     Example 26 may include the method of example 25 and/or some other example herein, wherein the non-AP MLD may be an enhanced multilink single radio (eMLSR). 
     Example 27 may include an apparatus comprising means for: establishing a first communication link between a first non-AP STA of a non-AP MLD and a first AP of the AP MLD; establishing a second communication link between a second non-AP STA of the non-AP MLD and a second AP of the AP MLD; causing to send on the second communication link a frame from the second non-AP STA to the second AP, wherein the frame comprises availability information associated with the second non-AP STA. 
     Example 28 may include the apparatus of example 27 and/or some other example herein, wherein the availability information may be a bit set to 1 to indicate an unavailable status. 
     Example 29 may include the apparatus of example 27 and/or some other example herein, wherein the availability information may be a bit set to 0 to indicate an available status. 
     Example 30 may include the apparatus of example 27 and/or some other example herein, further comprising identifying a response frame from the second AP, wherein the response frame indicates acceptance or denial of the availability information. 
     Example 31 may include the apparatus of example 27 and/or some other example herein, wherein the non-AP MLD may be a non-simultaneous transmit receive (NSTR) device. 
     Example 32 may include the apparatus of example 27 and/or some other example herein, wherein a restricted target wake time (rTWT) may be established on the first communication link. 
     Example 33 may include the apparatus of example 32 and/or some other example herein, wherein an unavailability status of the second non-AP STA may be for a period of the rTWT. 
     Example 34 may include the apparatus of example 33 and/or some other example herein, wherein the non-AP MLD may be an enhanced multilink single radio (eMLSR). 
     Example 35 may include one or more non-transitory computer-readable media comprising instructions to cause an electronic device, upon execution of the instructions by one or more processors of the electronic device, to perform one or more elements of a method described in or related to any of examples 1-34, or any other method or process described herein. 
     Example 36 may include an apparatus comprising logic, modules, and/or circuitry to perform one or more elements of a method described in or related to any of examples 1-34, or any other method or process described herein. 
     Example 37 may include a method, technique, or process as described in or related to any of examples 1-34, or portions or parts thereof. 
     Example 38 may include an apparatus comprising: one or more processors and one or more computer readable media comprising instructions that, when executed by the one or more processors, cause the one or more processors to perform the method, techniques, or process as described in or related to any of examples 1-34, or portions thereof. 
     Example 39 may include a method of communicating in a wireless network as shown and described herein. 
     Example 40 may include a system for providing wireless communication as shown and described herein. 
     Example 41 may include a device for providing wireless communication as shown and described herein. 
     Embodiments according to the disclosure are in particular disclosed in the attached claims directed to a method, a storage medium, a device and a computer program product, wherein any feature mentioned in one claim category, e.g., method, can be claimed in another claim category, e.g., system, as well. The dependencies or references back in the attached claims are chosen for formal reasons only. However, any subject matter resulting from a deliberate reference back to any previous claims (in particular multiple dependencies) can be claimed as well, so that any combination of claims and the features thereof are disclosed and can be claimed regardless of the dependencies chosen in the attached claims. The subject-matter which can be claimed comprises not only the combinations of features as set out in the attached claims but also any other combination of features in the claims, wherein each feature mentioned in the claims can be combined with any other feature or combination of other features in the claims. Furthermore, any of the embodiments and features described or depicted herein can be claimed in a separate claim and/or in any combination with any embodiment or feature described or depicted herein or with any of the features of the attached claims. 
     The foregoing description of one or more implementations provides illustration and description, but is not intended to be exhaustive or to limit the scope of embodiments to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of various embodiments. 
     Certain aspects of the disclosure are described above with reference to block and flow diagrams of systems, methods, apparatuses, and/or computer program products according to various implementations. It will be understood that one or more blocks of the block diagrams and flow diagrams, and combinations of blocks in the block diagrams and the flow diagrams, respectively, may be implemented by computer-executable program instructions. Likewise, some blocks of the block diagrams and flow diagrams may not necessarily need to be performed in the order presented, or may not necessarily need to be performed at all, according to some implementations. 
     These computer-executable program instructions may be loaded onto a special-purpose computer or other particular machine, a processor, or other programmable data processing apparatus to produce a particular machine, such that the instructions that execute on the computer, processor, or other programmable data processing apparatus create means for implementing one or more functions specified in the flow diagram block or blocks. These computer program instructions may also be stored in a computer-readable storage media or memory that may direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable storage media produce an article of manufacture including instruction means that implement one or more functions specified in the flow diagram block or blocks. As an example, certain implementations may provide for a computer program product, comprising a computer-readable storage medium having a computer-readable program code or program instructions implemented therein, said computer-readable program code adapted to be executed to implement one or more functions specified in the flow diagram block or blocks. The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational elements or steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions that execute on the computer or other programmable apparatus provide elements or steps for implementing the functions specified in the flow diagram block or blocks. 
     Accordingly, blocks of the block diagrams and flow diagrams support combinations of means for performing the specified functions, combinations of elements or steps for performing the specified functions and program instruction means for performing the specified functions. It will also be understood that each block of the block diagrams and flow diagrams, and combinations of blocks in the block diagrams and flow diagrams, may be implemented by special-purpose, hardware-based computer systems that perform the specified functions, elements or steps, or combinations of special-purpose hardware and computer instructions. 
     Conditional language, such as, among others, “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain implementations could include, while other implementations do not include, certain features, elements, and/or operations. Thus, such conditional language is not generally intended to imply that features, elements, and/or operations are in any way required for one or more implementations or that one or more implementations necessarily include logic for deciding, with or without user input or prompting, whether these features, elements, and/or operations are included or are to be performed in any particular implementation. 
     Many modifications and other implementations of the disclosure set forth herein will be apparent having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the disclosure is not to be limited to the specific implementations disclosed and that modifications and other implementations are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.