PATENT DOCUMENT

Publication Number: US-11930381-B2
Application Number: US-202117337748-A
Country: US
Kind Code: B2

Title: Backup link for low latency communication

Abstract:
Some aspects of this disclosure include apparatuses and methods for implementing backup link establishment and operation for multi-link wireless communication networks such as a wireless local area network (WLAN). Some aspects relate to an electronic device including a transceiver configured to communicate over a wireless network and a processor communicatively coupled to the transceiver. The processor receives a message including information associated with a backup link from a second electronic device. The processor further receives data associated with data traffic from the second electronic device on a primary link of the wireless network. In response to a quality of the primary link being below a threshold, the processor receives a notification frame from the second electronic device on the backup link and receives additional data associated with the data traffic from the second electronic device on the backup link or on an other link informed by the notification frame.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a transceiver configured to communicate over a wireless network; and 
 a processor communicatively coupled to the transceiver and configured to:
 receive, from a second electronic device, a message comprising information associated with a backup link of the wireless network; 
 in response to receiving the message, transmit, to the second electronic device, a second message indicating that the electronic device supports using multiple links and indicating whether the electronic device supports using the backup link indicated in the message from the second electronic device; 
 receive, on a primary link of the wireless network, data associated with data traffic from the second electronic device; and 
 in response to a quality of the primary link being below a threshold,
 receive, from the second electronic device, a notification frame on the backup link; and 
 receive, from the second electronic device, additional data associated with the data traffic on the backup link or on another link in response to receiving the notification frame. 
 
 
 
     
     
       2. The electronic device of  claim 1 , wherein the second message further indicates that:
 the electronic device supports the backup link; 
 the backup link is associated with a first receiver of the electronic device, a second transceiver of the electronic device, or a second receiver of the electronic device, wherein the second receiver is configured to be turned into a third transceiver by transitioning a radio resource from the transceiver of the electronic device; and 
 capability information associated with the backup link. 
 
     
     
       3. The electronic device of  claim 1 , wherein the second message indicates an alternative backup link and the processor is further configured to:
 receive, from the second electronic device, a confirmation message. 
 
     
     
       4. The electronic device of  claim 1 , further comprising:
 a second transceiver configured to operate on a frequency associated with the backup link, 
 wherein the processor is further configured to set a power save schedule of the second transceiver based at least on a traffic schedule associated with the data or based at least on a power save schedule of the transceiver. 
 
     
     
       5. The electronic device of  claim 1 , further comprising:
 a second transceiver configured to operate on a frequency associated with the backup link, wherein the transceiver is configured to operate on a frequency associated with the primary link, wherein:
 the processor is configured to receive the data, on the primary link from the second electronic device, using the transceiver; 
 the processor is configured to receive the additional data, on the backup link from the second electronic device, using the second transceiver, and 
 the processor is further configured to set a power save schedule of the second transceiver based at least on a traffic schedule associated with the data or based at least on a power save schedule of the transceiver. 
 
 
     
     
       6. The electronic device of  claim 5 , wherein the second transceiver is in an awake state when the transceiver is in the awake state. 
     
     
       7. The electronic device of  claim 1 , further comprising:
 a receiver configured to scan channels in the wireless network over the backup link, 
 wherein the processor is further configured to set a scan schedule of the receiver based at least on a traffic schedule associated with the data or based at least on a power save schedule of the transceiver. 
 
     
     
       8. The electronic device of  claim 1 , further comprising:
 a receiver configured to scan channels in the wireless network, wherein the transceiver is configured to operate on a frequency associated with the primary link, wherein:
 the processor is configured to receive the data, on the primary link from the second electronic device, using the transceiver; and 
 the processor is configured to receive the notification frame, on the backup link, using the receiver. 
 
 
     
     
       9. The electronic device of  claim 8 , wherein the notification frame comprises at least one of a notification that the quality of the primary link is below the threshold or information associated with the other link to be used for continued data communication. 
     
     
       10. The electronic device of  claim 8 , wherein the processor is configured to set a scan schedule of the receiver based at least on a traffic schedule associated with the data. 
     
     
       11. The electronic device of  claim 10 , wherein the receiver is in an awake state when the transceiver is in the awake state. 
     
     
       12. The electronic device of  claim 8 , wherein the processor is configured to set a scan schedule of the receiver based at least on a power save schedule of the transceiver. 
     
     
       13. The electronic device of  claim 1 , further comprising:
 an auxiliary receiver-only radio configured to operate on a frequency associated with the backup link, wherein the transceiver is configured to operate on a frequency associated with the primary link. 
 
     
     
       14. The electronic device of  claim 13 , wherein:
 the processor is configured to receive the data on the primary link, from the second electronic device, using the transceiver; 
 the auxiliary receiver-only radio is in a listening mode prior to the reception of the notification frame on the backup link, from the second electronic device, of the notification frame, and 
 the processor is configured to transition a radio resource from the transceiver on the primary link to the auxiliary receiver-only radio, upon the reception of the notification frame on the backup link, and to subsequently receive the additional data on the backup link, using the auxiliary receiver-only radio. 
 
     
     
       15. A method, comprising:
 receiving, at a first electronic device, a message from a second electronic device, wherein the message comprises information associated with a backup link of a wireless network; 
 in response to receiving the message, transmitting, by the first electronic device to the second electronic device, a second message indicating that the first electronic device supports using multiple links and indicating whether the first electronic device supports using the backup link indicated in the message from the second electronic device; 
 receiving, at the first electronic device and from the second electronic device, data associated with traffic on a primary link of the wireless network; and 
 in response to a quality of the primary link being below a threshold,
 receiving additional data associated with the traffic from the second electronic device on the backup link; or 
 receiving a notification frame from the second electronic device on the backup link, wherein the notification frame comprises at least one of a notification that the quality of the primary link is below the threshold or information associated with a communication link to be used for communicating the additional data. 
 
 
     
     
       16. The method of  claim 15 , wherein the first electronic device comprises a first transceiver configured to operate on a frequency associated with the primary link and a second transceiver configured to operate on a frequency associated with the backup link, the method further comprising:
 setting a power save schedule of the second transceiver based at least on a traffic schedule associated with the data of the traffic; or 
 setting a power save schedule of the second transceiver based at least on a power save schedule of the first transceiver. 
 
     
     
       17. The method of  claim 15 , further comprising:
 transmitting, to the second electronic device, a second message indicating an alternative backup link; and 
 receiving, from the second electronic device, a confirmation message. 
 
     
     
       18. The method of  claim 15 , wherein the first electronic device comprises a transceiver configured to operate on a frequency associated with the primary link and a receiver configured to scan channels in the wireless network over the backup link, and the method further comprising:
 setting a scan schedule of the receiver based at least on a traffic schedule associated with the data or based at least on a power save schedule of the transceiver. 
 
     
     
       19. A non-transitory computer-readable medium storing instructions that, when executed by a processor of a first electronic device, cause the processor to perform operations, the operations comprising:
 receiving a message from a second electronic device, wherein the message comprises information associated with a backup link of a wireless network; 
 in response to receiving the message, transmitting, to the second electronic device, a second message indicating that the first electronic device supports using multiple links and indicating whether the first electronic device supports using the backup link indicated in the message from the second electronic device; 
 receiving, from the second electronic device, data associated with traffic on a primary link of the wireless network; and 
 in response to a quality of the primary link being below a threshold,
 receiving a notification frame from the second electronic device on the backup link; and 
 receiving additional data associated with the traffic from the second electronic device on the backup link or on another link in response to receiving the notification frame. 
 
 
     
     
       20. The non-transitory computer-readable medium of  claim 19 , wherein the first electronic device comprises a transceiver configured to operate on a frequency associated with the primary link and a receiver configured to scan channels in the wireless network over the backup link, and the operations further comprising:
 setting a scan schedule of the receiver based at least on a traffic schedule associated with the data or based at least on a power save schedule of the transceiver.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims the benefit of U.S. Provisional Patent Application No. 63/044,474, filed on Jun. 26, 2020, which is hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     Field 
     The described aspects generally relate to channel access in wireless communications. For example, the aspects of this disclosure relate to establishing and using backup link(s) for low latency communication in multi-link wireless communication networks, such as a wireless local area network (WLAN). 
     Related Art 
     A first station can communicate data with a second station using a transceiver over a communication link. If the first link becomes unavailable, the first and second stations need to wait for the communication link to become available again before the first and second stations can continue. Additionally, or alternatively, the first and second station need to go long association procedures to reestablish their communication. 
     SUMMARY 
     Some aspects of this disclosure include apparatuses and methods for implementing backup link establishment and operation for multi-link wireless communication networks, such as a wireless local area network (WLAN). The backup link establishment and operation for a multi-link WLAN, described in this disclosure can assist devices in the WLAN (e.g., an access point (AP), a station (STA), etc.) to realize one or more benefits, such as faster switching between links, better utilization of channel resources, reduce channel access time upon channel switching, and/or save power and/or time. 
     Some aspects of this disclosure relate to an electronic device. The electronic device includes a transceiver configured to communicate over a wireless network and a processor communicatively coupled to the transceiver. The processor is configured to receive a message from a second electronic device. The message includes information associated with a backup link of the wireless network. The processor is further configured to receive data associated with data traffic from the second electronic device on a primary link of the wireless network. In response to a quality of the primary link being below a threshold, the processor receives a notification frame from the second electronic device on the backup link and receives additional data associated with the data traffic from the second electronic device on the backup link, or on another, link in response to the notification frame. 
     In some examples, the processor is further configured to transmit, to the second electronic device, a second message indicating that the electronic device supports the backup link and the backup link is associated with a receiver or a second transceiver of the electronic device. 
     In some examples, the processor is further configured to transmit, to the second electronic device, a second message indicating an alternative backup link and to receive, from the second electronic device, a third message confirming an updated backup link. 
     In some examples, the electronic device further includes a second transceiver configured to operate on a frequency associated with the backup link. The transceiver can be configured to operate on a frequency associated with the primary link. In some examples, the processor can be configured to receive the data, on the primary link from the second electronic device, using the transceiver. In some examples, the processor can be configured to receive the additional data, on the backup link from the second electronic device, using the second transceiver. 
     In some examples, the processor is configured to set a power save schedule of the second transceiver, configured to operate on a frequency of the backup link, based at least on a traffic schedule associated with the data. Alternatively, the processor is configured to set a power save schedule of the second transceiver, configured to operate on a frequency of the backup link, based at least on a power save schedule of the transceiver, configured to operate on a frequency of the primary link. 
     In some examples, the electronic device further includes a receiver configured to scan channels in the network. The transceiver is configured to operate on a frequency associated with the primary link. In some examples, the processor can be configured to receive the data, on the primary link from the second electronic device, using the transceiver. In some examples, the processor can be configured to receive the notification frame, on the backup link, using the receiver. 
     In some examples, the electronic device further includes an auxiliary radio configured to operate in a listening mode, the auxiliary radio being capable of receiving simple frames (e.g., a notification frame) on the backup link, and the transceiver is configured to operate on a frequency associated with the primary link. In some examples, the processor can be configured to receive the data on the primary link, from the second electronic device, using the transceiver. the auxiliary receiver-only radio can be in a listening mode prior to the reception on the backup link, from the second electronic device, of the notification frame. After a device implementation-specific delay upon receiving the notification frame, the first electronic device is able to both transmit and receive on the back up link by transitioning radio resources from the transceiver to the auxiliary radio, and therefore backup link becomes the new low latency communication link. 
     In some examples, the notification frame includes at least one of a notification that the quality of the primary link is below the threshold or information associated with the other link for continued data communication. In some examples, the processor is configured to set a scan schedule of the receiver based at least on a traffic schedule associated with the data. Alternatively, the processor is configured to set a scan schedule of the receiver based at least on a power save schedule of the transceiver that is configured to operate on a frequency of the primary link. 
     In some examples, the data is associated with an item of low latency traffic. In some examples, the electronic device is a non-access point station and the second electronic device is an access point in the wireless network. In some examples, the electronic device is a non-access point station and the second electronic device is a non-access point station in the wireless network. 
     Some aspects of the disclosure relate to a method that includes receiving, at a first electronic device, a message from a second electronic device. The message includes information associated with a backup link of a wireless network. The method further includes receiving, at the first electronic device and from the second electronic device, data associated with low latency traffic on a primary link of the wireless network. In response to a quality of the primary link being below a threshold, the method includes receiving additional data associated with the low latency traffic from the second electronic device on the backup link and receiving a notification frame from the second electronic device on the backup link. The notification frame includes at least one of a notification that the quality of the primary link is below the threshold or information associated with a communication link to be used for communicating the additional data. 
     Some aspects of the disclosure relate to a non-transitory computer-readable medium storing instructions that, when executed by a processor of a first electronic device, cause the processor to perform operations including receiving a message from a second electronic device that includes information associated with a backup link of a wireless network. The operations further include receiving, from the second electronic device, data associated with low latency traffic on a primary link of the wireless network. In response to a quality of the primary link being below a threshold, the operations include receiving a notification frame from the second electronic device on the backup link and receiving additional data associated with the low latency traffic from the second electronic device on the backup link or on another link in response to the notification frame. 
     Some aspects of the disclosure relate to an electronic device that includes a transceiver configured to communicate over a wireless network and a processor communicatively coupled to the transceiver. The processor is configured to transmit, to a second electronic device, a message that includes information associated with a backup link of the wireless network. The processor further transmits data associated with data traffic to the second electronic device on the primary link of the wireless network. In response to a determination that a quality of the primary link is below a threshold, the processor transmits a notification frame to the second device on the backup link and transmits additional data associated with the data traffic to the second device on the backup link, or on another link, in response to the notification frame. 
     Some aspects of the disclosure relate to a method that includes transmitting, by a first electronic device, a message to a second electronic device that includes information associated with a backup link of a wireless network. The method further includes transmitting data associated with data traffic to the second electronic device on the primary link of the wireless network. In response to a determination that a quality of the primary link is below a threshold, the method includes transmitting a notification frame to the second device on the backup link and transmitting additional data associated with the data traffic to the second device on the backup link, or on another link, indicated by the notification frame. 
     Some aspects relate to a non-transitory computer-readable medium storing instructions that, when executed by a processor of a first electronic device, cause the processor to perform operations including transmitting, to a second electronic device, a message that includes information associated with a backup link of a wireless network. The operations further include transmitting data associated with data traffic to the second electronic device on the primary link of the wireless network. In response to a determination that a quality of the primary link is below a threshold, the operations include transmitting a notification frame to the second device on the backup link and transmitting additional data associated with the data traffic to the second device on the backup link or on another link indicated by the notification frame. 
     This Summary is provided for purposes of illustrating some aspects of the disclosure to provide an understanding of the subject matter described herein. Accordingly, the above-described features are examples and should not be construed to narrow the scope or spirit of the subject matter in this disclosure. Other features, aspects, and advantages of this disclosure will become apparent from the following Detailed Description, Figures, and Claims. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The accompanying drawings, which are incorporated herein and form part of the specification, illustrate the present disclosure and, together with the description, further serve to explain the principles of the disclosure and enable a person of skill in the relevant art(s) to make and use the disclosure. 
         FIG.  1 A  illustrates an example system implementing backup link establishment and operation in a communication network, according to some aspects of the disclosure. 
         FIG.  1 B  illustrates an example multi-link communication between two devices, according to some aspects of the disclosure. 
         FIG.  2    illustrates a block diagram of an example wireless system of an electronic device implementing the backup link establishment and operation in a communication network, according to some aspects of the disclosure. 
         FIG.  3    illustrates an example of communication between an access point (AP) and a station (STA), according to some aspects of the disclosure, according to some aspects of the disclosure. 
         FIG.  4    illustrates an example of communications between an AP MLD and a non-AP MLD to establish the backup link, according to some aspects of the disclosure. 
         FIGS.  5 A,  5 B, and  5 C  illustrate three example backup links between an AP MLD and a non-AP MLD, according to some aspects of the disclosure. 
         FIGS.  6 - 7    illustrate example operation of a backup link enabled by a transceiver, according to some aspects of the disclosure. 
         FIGS.  8 - 9    illustrate example operation of a backup link enabled by a receiver, according to some aspects of the disclosure. 
         FIG.  10    illustrates an example method for a wireless system supporting and implementing backup link establishment and operation for multi-link wireless communication networks, such as a wireless local area network (WLAN), according to some aspects of the disclosure. 
         FIG.  11    illustrates an example method for a wireless system supporting and implementing backup link establishment and operation for multi-link wireless communication networks such as a wireless local area network (WLAN), according to some aspects of the disclosure. 
         FIG.  12    illustrates an example computer system for implementing some aspects of the disclosure or portion(s) thereof. 
     
    
    
     The present disclosure is described with reference to the accompanying drawings. In the drawings, generally, like reference numbers indicate identical or functionally similar elements. Additionally, generally, the left-most digit(s) of a reference number identifies the drawing in which the reference number first appears. 
     DETAILED DESCRIPTION 
     Some aspects of this disclosure include apparatuses and methods for implementing backup link establishment and operation for multi-link wireless communication networks, such as a wireless local area network (WLAN). The backup link establishment and operation for WLAN of the aspects of this disclosure can assist the devices in the WLAN (e.g., an access point (AP), a station (STA)) to faster switch between links to reduce communication latency and have fewer service interruption, to better utilize channel resources, and/or to save power. 
     According to some aspects of the disclosure, the backup link establishment and operation for WLAN can be implemented with communication techniques compatible with Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards (such as, but not limited to, IEEE 802.11ac, IEEE 802.11ax, IEEE 802.11bc, IEEE 802.11bd, IEEE 802.11be, etc.). However, the aspects of this disclosure can also be applied to operations in other multi-link communication networks operating in accordance with any protocol(s). 
       FIG.  1 A  illustrates an example system  100  implementing the backup link establishment and operation in a communication network (such as, but not limited to, a multi-link communication network), according to some aspects of the disclosure. Example system  100  is provided for the purpose of illustration only and does not limit the disclosed aspects. System  100  may include, but is not limited to, access point (AP) multi-link device (MLD)  110 , non-AP MLDs  120 , and network  130 . Non-AP MLDs  120   a - 120   c  may include, but are not limited to, Wireless Local Area Network (WLAN) stations such as wireless communication devices, smart phones, laptops, desktops, tablets, personal assistants, monitors, televisions, wearable devices, gaming devices and the like. AP MLD  110  may include but is not limited to WLAN electronic devices such as a wireless router, a wearable device (e.g., a smart watch), a wireless communication device (e.g., a smart phone), a gaming device, or a combination thereof. Network  130  may be the Internet and/or a WLAN. Non-AP MLD  120 &#39;s communications are shown as wireless communications  140 . The communication between AP MLD  110  and non-AP MLD  120  can take place using wireless communications  140   a - 140   c.  The wireless communications  140   a - 140   c  can be based on a wide variety of wireless communication techniques. These techniques can include, but are not limited to, techniques based on IEEE 802.11 (such as, but not limited to IEEE 802.11ac, IEEE 802.11ax, IEEE 802.11bc, IEEE 802.11bd, IEEE 802.11be, IEEE 802.11v, etc. standards). 
     According to some aspects, AP MLD  110  and non-AP MLDs  120  are configured to implement a multi-link communication. In other words, AP MLD  110  and non-AP MLDs  120  are configured to implement and support simultaneous or substantially simultaneous data transfer using multiple MAC/PHY links. For example,  FIG.  1 B  illustrates an example multi-link communication between two devices, according to some aspects of the disclosure. 
     As illustrated in  FIG.  1 B , non-AP MLD  120   a  and AP MLD  110  can communicate with each other using multiple links  150   a - 150   c.  In other words, non-AP MLD  120   a  and AP MLD  110  can use multiple MAC/PHY links  150   a - 150   c  to simultaneously or substantially simultaneously transfer data. Although three links  150  are illustrated, the aspects of this disclosure are not limited to this example and any number of links  150  can be implemented. The links  150  can include different wireless channels, according to some aspects. For example, each wireless channel/link  150  can be defined based on its respective frequency that is different from the others. However, the aspects of this disclosure are not limited to wireless channels and other MAC/PHY layer links can be used as links  150  for communication between non-AP MLD  120   a  and AP MLD  110 . 
     Also, although links  150   a - 150   c  are shown as links between non-AP MLD  120   a  and AP MLD  110 , the aspects of this disclosure are not limited to this example. In some aspects, the multi-link communication can be between two APs (and/or two AP MLDs) and the aspects of this disclosure implementing the backup link establishment and operation can be applied between two APs (and/or two AP MLDs). Additionally or alternatively, the multi-link communication can be between two stations (STAs) (e.g., two STAs of two non-AP MLDs) and the aspects of this disclosure implementing the backup link establishment and operation can be applied to peer-to-peer (P2P) communication. For example, the communication between two STAs (and links  150 ) can be direct communication (and direct links) between these STAs. Additionally or alternatively, the communication between two STAs (and links  150 ) is through AP MLD  110 . In this example, wireless communications  140   a  and  140   b,  as shown in  FIG.  1 A , can include links  150   a - 150   c  of  FIG.  1 B . 
     According to some aspects, the backup link establishment and operation can be used for low latency (LL) communication. However, the aspects of this disclosure are not limited to this example, and the backup link establishment and operation of this disclosure can be used for other communications. In some examples, the low latency communication and low latency capabilities of system  100  can be used for gaming applications. Additionally or alternatively, the low latency communication and low latency capabilities of system  100  can be used for interactive video applications. Additionally or alternatively, the low latency communication and low latency capabilities of system  100  can be used for video application(s) providing interactive play, such as but not limited to, virtual reality (VR), augmented reality (AR), and the like. For example, the low latency communication and low latency capabilities of system  100  can be used for video application(s) that include a control loop, where a feedback input exists between, for example, a viewer of the video application and the video content. Additionally, or alternatively, the low latency communication and low latency capabilities of system  100  can be used for other applications where a control loop (e.g., a feedback loop) exists between non-AP MLD  120  and AP MLD  110  (and/or between non-AP MLD  120   a  and non-AP MLD  120   b,  and/or between two AP MLDs). Additionally, or alternatively, the low latency communication and low latency capabilities of system  100  can be used in industrial uses. For example, in communications between sensors and an AP MLD, where it is important to meet the low latency requirements. However, the aspects of this disclosure are not limited to these examples of low latency communications and the backup link establishment and operation aspect of this disclosure can be applied to other examples of low latency communications or communication that does not require low latency. 
     According to some aspects, non-AP MLD  120   a  and AP MLD  110  can communicate over link  150   a,  as illustrated in  FIG.  1 B . Non-AP MLD  120   a  and AP MLD  110  can use link  150   a  to achieve low latency capabilities. In some examples of this disclosure, and as discussed in more detail below, if the quality of link  150   a  deteriorates, AP MLD  110  and non-AP MLD  120   a  can quickly switch the low latency communication to a different link (e.g., link  150   b ) that has a better quality. According to some aspects, AP MLD  110  can monitor the quality of link  150   a  (and other links). For example, AP MLD  110  can use information AP MLD  110  receives from non-AP MLD  120   a  (and/or other non-AP MLDs) to determine the quality of link  150   a  (and other links). In some examples, the quality of a link (e.g., link  150   a ) can include the amount of interference on the link, the amount of congestion on the link, the latency of the link, the signal to noise ratio of the link, and the like. However, the aspects of this disclosure are not limited to these examples and other metrics can be used to determine the quality of the link (e.g., link  150   a ). 
     If the quality of link  150   a  deteriorates (e.g., one or more metrics used to determine the quality of the link are below one or more predetermined thresholds), then link  150   a  is no longer suitable for continued data transmission or link quality change notification. In other words, when the quality of link  150   a  deteriorates, AP MLD  110  cannot use link  150   a  for the low latency communication with non-AP MLD  120   a.  Additionally, or alternatively, AP MLD  110  cannot use link  150   a  to communicate to non-AP MLD  120   a  to switch to another and better link (e.g., link  150   b ). 
     Because an AP MLD typically does not go into power save, and typically has a higher or the same number of transceivers than that of a non-AP MLD, a backup link is established to ensure a non-AP STA&#39;s availability to receive a notification from the AP MLD. Even without a backup link agreement, the non-AP typically is able to transmit a notification frame to the AP MLD when needed due to the availability of the AP MLD. 
     According to some aspects, AP MLD  110  and non-AP MLD  120   a  have established a backup link (e.g., link  150   b ). In these examples, the backup link  150   b  is not used for the low latency communication before the quality of link  150   a  deteriorates. In some examples, when the quality of link  150   a  deteriorates, AP MLD  110  can quickly switch to backup link  150   b  to continue to transmit the data associated with the low latency communication and non-AP MLD  120  can use backup link  150   b  to continue to receive and/or transmit the data. In these examples, backup link  150   b  can be used as the new low latency communication link. Since AP MLD  110  and non-AP MLD  120   a  had established link  150   b  as the backup link, switching the communication from link  150   a  to link  150   b  is fast, the link switch time is reduced, and the channel access time is reduced. Such a link switch initiated by the AP MLD  110  implies quality deterioration of link  150   a  and the link switch. In some examples, AP MLD  110  may also transmit an explicit link quality change and link switch notification frame to non-AP MLD  120   a  to indicate the link switch. In these examples, using the explicit link quality change and link switch notification frame, AP MLD  110  can notify non-AP MLD  120   a  of the link qualification deterioration of the primary low latency link  150   a  and of the new link to continue low latency communication to be backup link  150   b.  In some examples, the new link to continue low latency communication is another link that is not backup link  150   b.  Non-AP MLD  120   a  also switches its data transmission to AP MLD  110  to backup link  150   b  upon either the implicit or explicit notification. 
     Additionally, or alternatively, when the quality of link  150   a  deteriorates, AP MLD  110  can quickly switch to backup link  150   b  to transmit a link quality change and link switch notification frame to non-AP MLD  120   a  on backup link  150   b.  As discussed in more detail below, non-AP MLD  120   a  may use a receive-only auxiliary radio (e.g., a scan radio, a radio for non-scanning receive-only purposes, etc.) for link  150   b.  Non-AP MLD  120   a  receives the link quality change and link switch notification frame on backup link  150   b,  which informs non-AP MLD  120   a  that the quality of link  150   a  deteriorates and informs non-AP MLD  120   a  of a new link (e.g., link  150   c ) to be used as the new low latency communication link. Since AP MLD  110  and non-AP MLD  120   a  had established link  150   b  as the backup link for the notification frame, switching the communication from link  150   a  to link  150   c  is fast due to the notification frame containing the information of using  150   c  as the new link , the link switch time is reduced, and the channel access time may be reduced. 
     In some aspects, the notification frame can be either a management frame type or a control frame type. However, the aspects of this disclosure can include other frame types for the notification frame. 
       FIG.  2    illustrates a block diagram of an example wireless system  200  of an electronic device implementing the backup link establishment and operation for multi-link communication network, according to some aspects of the disclosure. System  200  may be any of the electronic devices (e.g., AP MLD  110 , non-AP MLD  120 ) of system  100 . System  200  includes processor  210 , one or more transceivers  220   a - 220   n,  one or more receiver(s)  221 , communication infrastructure  240 , memory  250 , operating system  252 , application  254 , and antenna  260 . Illustrated systems are provided as exemplary parts of wireless system  200 , and system  200  can include other circuit(s) and subsystem(s). Also, although the systems of wireless system  200  are illustrated as separate components, the aspects of this disclosure can include any combination of these, less, or more components. 
     Memory  250  may include random access memory (RAM) and/or cache, and may include control logic (e.g., computer software) and/or data. Memory  250  may include other storage devices or memory such as, but not limited to, a hard disk drive and/or a removable storage device/unit. According to some examples, operating system  252  can be stored in memory  250 . Operating system  252  can manage transfer of data from memory  250  and/or one or more applications  254  to processor  210 , one or more transceivers  220   a - 220   n,  and/or one or more receiver(s)  221 . In some examples, operating system  252  maintains one or more network protocol stacks (e.g., Internet protocol stack, cellular protocol stack, and the like) that can include a number of logical layers. At corresponding layers of the protocol stack, operating system  252  includes control mechanism and data structures to perform the functions associated with that layer. 
     According to some examples, application  254  can be stored in memory  250 . Application  254  can include applications (e.g., user applications) used by wireless system  200  and/or a user of wireless system  200 . The applications in application  254  can include applications such as, but not limited to, Siri™, FaceTime™, radio streaming, video streaming, remote control, gaming application(s), and/or other user applications. 
     System  200  can also include communication infrastructure  240 . Communication infrastructure  240  provides communication between, for example, processor  210 , one or more transceivers  220   a - 220   n,  one or more receiver(s)  221 , and memory  250 . In some implementations, communication infrastructure  240  may be a bus. Processor  210  together with instructions stored in memory  250  performs operations enabling wireless system  200  of system  100  to implement the backup link establishment and operation as described herein. Additionally, or alternatively, one or more transceivers  220   a - 220   n  and/or one or more receiver(s)  221  perform operations enabling wireless system  200  of system  100  to implement the backup link establishment and operation as described herein. 
     One or more transceivers  220   a - 220   n  transmit and receive communications signals that support the backup link establishment and operation, according to some aspects, and may be coupled to antenna  260 . One or more auxiliary radios (or, receiver(s))  221  receive communications signals that support the backup link establishment and operation, according to some aspects, and may be coupled to antenna  260 . (Herein, transceivers can also be referred to as radios). Antenna  260  may include one or more antennas that may be the same or different types. One or more transceivers  220   a - 220   n  and/or one or more receiver(s)  221  allow system  200  to communicate with other devices that may be wired and/or wireless. In some examples, one or more transceivers  220   a - 220   n  can include processors, controllers, radios, sockets, plugs, buffers, and like circuits/devices used for connecting to and communication on networks. According to some examples, one or more transceivers  220   a - 220   n  include one or more circuits to connect to and communicate on wired and/or wireless networks. 
     According to some aspects of this disclosure, one or more transceivers  220   a - 220   n  can include a cellular subsystem, a WLAN subsystem, and/or a Bluetooth™ subsystem, each including its own radio transceiver and protocol(s) as will be understood by those skilled arts based on the discussion provided herein. In some implementations, one or more transceivers  220   a - 220   n  can include more or fewer systems for communicating with other devices. 
     In some examples, one or more transceivers  220   a - 220   n  can include one or more circuits (including a cellular transceiver) for connecting to and communicating on cellular networks. The cellular networks can include, but are not limited to, 3G/4G/5G networks such as Universal Mobile Telecommunications System (UMTS), Long-Term Evolution (LTE), and the like. 
     Additionally, or alternatively, one or more transceivers  220   a - 220   n  can include one or more circuits (including a Bluetooth™ transceiver) to enable connection(s) and communication based on, for example, Bluetooth™ protocol, the Bluetooth™ Low Energy protocol, or the Bluetooth™ Low Energy Long Range protocol. For example, transceiver  220   n  can include a Bluetooth™ transceiver. 
     Additionally, one or more transceivers  220   a - 220   n  can include one or more circuits (including a WLAN transceiver) to enable connection(s) and communication over WLAN networks such as, but not limited to, networks based on standards described in IEEE 802.11 (such as, but not limited to IEEE 802.11ac, IEEE 802.11ax, IEEE 802.11bc, IEEE 802.11bd, IEEE 802.11be, etc.). For example, transceiver  220   a  can enable connection(s) and communication over a multi-link WLAN network having a first link (e.g., link  150   a ) associated with 2.4 GHz wireless communication channel. For example, transceiver  220   b  can enable connection(s) and communication over the multi-link WLAN network having a second link (e.g., link  150   b ) associated with 5 GHz wireless communication channel. For example, transceiver  220   c  can enable connection(s) and communication over the multi-link WLAN network having a third link (e.g., link  150   c ) associated with 6 GHz wireless communication channel. However, the aspects of this disclosure are no limited to these wireless channels and other PHY layer links and/or other wireless channels can be used. 
     Additionally, or alternatively, wireless system  200  can include one WLAN transceiver configured to operate at two or more links. Processor  210  can be configured to control the one WLAN transceiver to switch between different links, according to some examples. For example, transceiver  220   a  can enable connection(s) and communication over a multi-link WLAN network having a first link (e.g., link  150   a ) associated with 2.4 GHz wireless communication channel. And transceiver  220   b  can enable connection(s) and communication over the multi-link WLAN network having a second link (e.g., link  150   b ) associated with 5 GHz wireless communication channel and can enable connection(s) and communication over the multi-link WLAN network having a third link (e.g., link  150   c ) associated with 6 GHz wireless communication channel. According to some aspects of the disclosure, the switching from the first link to the second link can include using a transceiver (e.g., transceiver  220   b ) associated with the second link instead of the transceiver (e.g., transceiver  220   a ) associated with the first link. Additionally, or alternatively, the switching from the first link to the second link can include controlling a single transceiver (e.g., transceiver  220 ) to operate at the frequency of the second link instead of operating at the frequency of the first link. 
     According to some aspects, system  200  can optionally include one or more receiver(s)  221 . In some examples, receiver  221  can be a receive-only receiver, for example, a receive-only auxiliary radio. In a non-limiting example, receiver  221  can be a scan radio. In some examples, receiver  221  can be a low power radio that can scan through each channel(s) of a frequency band/link and listen for per channel dwell time. Additionally, or alternatively, receiver  221  can obtain statistics indicating a corresponding channel quality. Receiver  221  can repeat such operation every scan interval. In another non-limiting example, receiver  221  can be a non-scanning radio used for non-scanning purposes. In one example, system  200  can include one receiver  221 , which can scan channels in a 2.4 GHz band, in a 5 GHz band, and/or in a 6 GHz band. Alternatively, system  200  can include more than one receiver  221 , where a first receiver can scan channels in a 2.4 GHz band and a second receiver can scan in a 5 GHz band and/or in a 6 GHz band. Alternatively, system  200  can include more than one receiver  221 , where a first receiver can scan channels in a 2.4 GHz band, and a second receiver can scan in a 5 GHz band, and a third receiver can scan in a 6 GHz band. In other examples, receiver  221  is an auxiliary radio that is a receiver only but can be turned into a transceiver by moving radio resource(s) from transceiver  220  to receiver  221 . However, these are provided as examples, and the aspects of this disclosure can include other number of receivers, frequency bands, and/or configurations. In some examples, one or more receiver(s)  221  can include processors, controllers, radios, sockets, plugs, buffers, and like circuits/devices used for scanning on networks. 
     According to some aspects of this disclosure, processor  210 , alone or in combination with computer instructions stored within memory  250 , one or more transceiver  220   a - 220   n , and/or one or more receiver(s)  221  implements the backup link establishment and operation in the multi-link communication network as discussed herein. As discussed in more detail below with respect to  FIGS.  3 - 11   , processor  210  can implement the backup link establishment and operation in the multi-link communication network of  FIGS.  1 A,  1 B, and  2   . 
       FIG.  3    illustrates one exemplary communication between AP MLD (multi-link device)  310  and non-AP MLD  320 , according to some aspects of the disclosure. In this example, AP MLD  310  and non-AP MLD  320  can communicate using a multi-link WLAN network having two or more links. For example, AP MLD  310  and non-AP MLD  320  can communicate using links  350   a - 350   c.  In some examples, links  350  can be and/or include links  150  of  FIG.  1 B . In some examples, AP MLD  310  can include AP MLD  110  of  FIGS.  1 A and  1 B  and non-AP MLD  320  can include one of non-AP MLDs  120   a - 120   c  of  FIGS.  1 A and  1 B . 
     In a non-limiting example, AP MLD  310  can maintain the same or higher number of simultaneous communication links than non-AP MLD  320 . According to some aspects, AP MLD  310  can include three transceivers  330   a - 330   c  (e.g., AP 1 -AP 3 ). For example, AP MLD  310  can include transceiver  330   a  (e.g., AP 1 ) configured to enable connection(s) and communication over a multi-link WLAN network having the first link (e.g., link  350   a ) associated with 2.4 GHz wireless communication channel. For example, AP MLD  310  can include transceiver  330   b  (e.g., AP 2 ) configured to enable connection(s) and communication over the multi-link WLAN network having a second link (e.g., link  350   b ) associated with 5 GHz wireless communication channel. For example, AP MLD  310  can include transceiver  330   c  (e.g., AP 3 ) configured to enable connection(s) and communication over the multi-link WLAN network having a third link (e.g., link  350   c ) associated with 6 GHz wireless communication channel. In some examples, AP MLD  310  can conduct communication on 2.4 GHz, 5 GHz, and 6 GHz links simultaneously (e.g., independently from each other). However, the aspects of this disclosure are no limited to these wireless channels and other PHY layer links and/or other wireless channels can be used. Also, AP MLD  310  can include less or more transceivers. 
     According to some aspects, non-AP MLD  320  can include two transceivers  340   a - 340   b  (e.g., STA 1  and STA 2 ). For example, non-AP MLD  320  can include transceiver  340   a  (e.g., STA 1 ) configured to enable connection(s) and communication over a multi-link WLAN network having the first link (e.g., link  350   a ) associated with 2.4 GHz wireless communication channel. For example, non-AP MLD  320  can include transceiver  340   b  (e.g., STA 2 ) configured to enable connection(s) and communication over the multi-link WLAN network having a second link (e.g., link  350   b ) associated with 5 GHz wireless communication channel or configured to enable connection(s) and communication over the multi-link WLAN network having a third link (e.g., link  350   c ) associated with 6 GHz wireless communication channel. In some examples, non-AP MLD  320  uses transceiver  340   b  (e.g., STA 2 ) for data communication in either 5 GHz link or 6 GHz link, but not both links simultaneously. In some examples, the unused 5 GHz link or 6 GHz link is called a virtual link. However, the aspects of this disclosure are no limited to these wireless channels and other PHY layer links and/or other wireless channels can be used. Also, non-AP MLD  320  can include less or more transceivers. 
     According to some aspects, non-AP MLD  320  can include one or more optional receiver(s)  341 . The receiver  341  can be a receive-only auxiliary radio. In some examples, receiver  341  can be a receive-only auxiliary radio such as, but not limited to, a scan radio. In some examples, receiver  341  can be a receive-only auxiliary radio such as, but not limited to, a receive-only radio used for non-scanning purpose(s). In some other examples, receiver  341  can be turned into a transceiver by moving radio resource(s) from transceiver(s)  340  to receiver  341 . According to some examples, receiver  341  can be configured to receive data and/or scan channel(s) over a first link (e.g., link  350   a ) associated with 2.4 GHz wireless communication link. Additionally, or alternatively, receiver  341  can be configured to receive data and/or scan channel(s) over a second link (e.g., link  350   b ) associated with 5 GHz wireless communication link. Additionally, or alternatively, receiver  341  can be configured to receive data and/or scan channel(s) over a third link (e.g., link  350   c ) associated with 6 GHz wireless communication link. In some examples, non-AP MLD  320  can include more than one receiver  341 , each one of receivers  341  can be configured to operate at one or more wireless communication links. However, the aspects of this disclosure are not limited to these wireless channels and other PHY layer links and/or other wireless channels can be used. 
     In a non-limiting example, as illustrated in  FIG.  3   , link  350   b  can be a primary link where AP MLD  310  and non-AP MLD  320  use to communicate the low latency data/traffic (herein referred to as primary low latency link). In this example, link  350   c  can be a virtual link, which can be used for communication but cannot be used simultaneously with link  350   b.  As discussed in more detail below, link  350   a  can be established as the backup link. Additionally, or alternatively, a link between receiver  341  of non-AP MLD  320  and AP MLD  310  can be established as the backup link. 
     In some examples, the low latency communication is conducted over, for example, primary low latency link  350   b,  as a result of an explicit or an implicit agreement between AP MLD  310  and non-AP MLD  320 . In a non-limiting example of an explicit agreement, during an initial link setup between AP MLD  310  and non-AP MLD  320 , AP MLD  310  and non-AP MLD  320  can agree that link  350   b  is used for low latency communication. For example, during an association operation (e.g., using association request from non-AP MLD  320  to AP MLD  310  and/or using association response form AP MLD  310  to non-AP MLD  320 ) and/or the other operation (e.g., multi-link setup, TID mapping), AP MLD  310  and non-AP MLD  320  can negotiate to use link  350   b  for low latency communication. Additionally, or alternatively, AP MLD  310  and non-AP MLD  320  can negotiate the link to use for low latency communication during the multi-link link setup. In some examples, the explicit agreement can include mapping traffic identifiers (TIDs) for low latency traffic only to a specific link (e.g., link  350   b ). 
     In a non-limiting example of an implicit agreement, other schemes, such as but not limited to trigger based communication scheme can result in the low latency traffic being communicated over a specific link (e.g., link  350   b ). In other words, some schemes can imply that a link is to be used as the primary link for the low latency traffic. In this example, no explicit agreement is made between AP MLD  310  and non-AP MLD  320  as which link is used for low latency communication. In the non-limiting example of the trigger based communication scheme, AP MLD  310  can trigger non-AP MLD  320  on a specific link (e.g., link  350   b ) for non-AP MLD  320  to send low latency traffic to AP MLD  310 . Since non-AP MLD  320  is being triggered, for example, a plurality of times on the specific link, non-AP MLD  320  and/or AP MLD  310  can imply that this specific link is the primary link for, for example, the low latency traffic. In another non-limiting example of the trigger based communication scheme, non-AP MLD  320  can ask AP MLD  310  to be triggered at a specific link (e.g., link  350   b ) for transmitting, for example, low latency traffic to AP MLD  310 . Since STA is asking, for example, a plurality of times to be triggered on the specific link, non-AP MLD  320  and/or AP MLD  310  can imply that this specific link is the primary link for, for example, the low latency traffic. 
     In some examples, if non-AP MLD  320  is not using transceiver  340   a  and/or receiver  341 , transceiver  340   a  and/or receiver  341  can be in a power save mode. One exemplary power save mode can include a loss-less power save mode or a lossy power save mode. In one example, another power save mode can include a Wireless Network Management (WNM) Sleep mode. 
       FIG.  4    illustrates exemplary communications between AP MLD  410  and non-AP MLD  420  to establish the backup link, according to some aspects of the disclosure. It is to be appreciated that not all operations in  FIG.  4    may be needed, and the operations may not be performed in the same order as shown in  FIG.  4   . 
     AP MLD  410  and non-AP MLD  420  can communicate the low latency traffic (or other types of traffic) on a primary low latency link. As discussed above, the primary low latency link can be an explicitly agreed on link or an implicitly agreed on link.  FIG.  4    illustrates an exemplary method  400  where AP MLD  410  and non-AP MLD  420  can negotiate one or more backup links. In some examples, method  400  can be part of initial link setup between AP MLD  410  and non-AP MLD  420 . For example, method  400  can be performed during an association operation (e.g., using association request from non-AP MLD  420  to AP MLD  410  and/or using association response form AP MLD  410  to non-AP MLD  420 ). Additionally, or alternatively, AP MLD  410  and non-AP MLD  420  can negotiate the backup link during the multi-link setup process. 
     AP MLD  410  sends message  401  to non-AP MLD  420  to announce the backup link, according to some aspects. For example, AP MLD  410  can determine and choose the backup link based on, for example, its own preference, and/or input received from non-AP MLD  420  and/or other non-AP MLDs prior to the backup link setup process  400 . The input from non-AP MLD  420  and/or other non-AP MLDs can include information corresponding to the links between non-AP MLD  420  (and/or other non-AP MLDs) and AP MLD  410 , and the capability of the non-AP MLD  420  and/or other non-AP MLDs. Non-limiting examples of such capability includes whether the non-AP MLDs have additional transceiver or receiver to be used as the backup links, and/or whether there is any limitation on the frame type and format that the non-AP MLDs are capable to receive on a backup link, and the like. Using this information, AP MLD  410  can choose the backup link. The backup link is different from and/or operates independently of the primary low latency link, according to some aspects. As a non-limiting example, the primary link is a 5 GHz wireless communication link and AP-MLD  410  chooses the 2.4 GHz wireless communication link as the backup link. Message  401  includes information associated with the elected backup link, according to some aspects. In some examples, message  401  is a frame used to communicate information associated with the elected backup link. In some examples, message  401  is an individually addressed frame sent only to non-AP MLD  420 . In some other examples, message  401  is a group addressed frame (including but not limited to a broadcast frame) sent to a group of non-AP MLDs including non-AP MLD  420 . 
     In response to message  401 , non-AP MLD  420  can send message  403  (e.g., a frame) to AP MLD  410 . In some examples, using message  403 , non-AP MLD  420  can inform AP MLD  410  whether non-AP MLD  420  supports using backup links. For example, if non-AP MLD  420  does not have an additional transceiver or additional receiver, non-AP MLD  420  can inform AP MLD  410  that non-AP MLD  420  does not support using backup link. However, if non-AP MLD  420  has an additional transceiver and/or additional receiver, non-AP MLD  420  can inform AP MLD  410  that non-AP MLD  420  supports using backup link. 
     Additionally, or alternatively, using message  403 , non-AP MLD  420  can inform AP MLD  410  whether non-AP MLD  420  supports the backup link announced by AP MLD  410 . For example, if non-AP MLD  420  does not have a transceiver that operates at the channel of the backup link, non-AP MLD  420  can inform AP MLD  410  that non-AP MLD  420  does not support the backup link. Additionally, or alternatively, non-AP MLD  420  can use message  403  to inform AP MLD  410  whether non-AP MLD  420  is using a receive-only receiver (e.g., a scan radio, a radio for non-scanning receive-only purposes, an auxiliary radio that can be turned into a transceiver by moving radio resource(s) from other transceiver to the radio auxiliary, etc.) or a transceiver of the backup link. Additionally, or alternatively, non-AP MLD  420  can use message  403  to communicate additional capability information to AP MLD  410 . The additional capability information can include, but are not limited to, supported bandwidth, Modulation and Coding Scheme (MCS) levels , Physical Protocol Data Unit (PPDU) type, and the like. In some examples, the additional capability information are the capability information associated with the backup link and/or associated with the receiver/transceiver associated with the backup link. Additionally, or alternatively, the additional capability information are the capability information associated with one or more links supported by non-AP MLD  420  and/or associated with the receiver/transceiver associated with the one or more links supported by non-AP MLD  420 . 
     In some examples, non-AP MLD  420  can use message  403  to indicate to AP MLD  410  that non-AP MLD  420  agrees with the announced backup link (e.g., endorses the backup link announced by AP MLD  410 ) and will use the announced backup link. Alternatively, non-AP MLD  420  can use message  403  to indicate to AP MLD  410  whether non-AP MLD  420  has an alternative preferred backup link. As a non-limiting example, the backup link is a 5 GHz wireless communication link and non-AP MLD  420  chooses the 2.4 GHz wireless communication link as the alternative backup link and communicates this backup link to AP MLD  410  using message  403 . 
     In some examples, message  403  is in the form of a single frame. In some other examples, message  403  can be more than one frame to convey all the necessary information. 
     In an optional step, and depending on message  403 , AP MLD  410  may change the backup link. If AP MLD  410  selects a different backup link based at least on message  403  (and/or other information from other non-AP MLDs), AP MLD  410  can send optional message  405  (e.g., a frame) to non-AP MLD  420  to announce the updated backup link. 
     If no changes are made to the backup link (e.g., no message  405 ), or after message  405  is transmitted by AP MLD  410 , non-AP MLD  420  and AP MLD  410  can start data communication  407 . According to some examples, data communication  407  can include low latency communication using the primary low latency link. Additionally, or alternatively, data communication  407  can include low latency communication using the backup link if the quality of the primary low latency link has deteriorated. As discussed above, the backup link is a link that can operate independently of the primary low latency link, according to some aspects. 
     In some examples, AP MLD  410  and non-AP MLD  420  switch the communication link between the primary low latency link and back up link even when the link quality does not deteriorate on the primary low latency link. 
     In some examples, the backup link can be updated during the communications between AP MLD  410  and non-AP MLD  420  and/or during the time that non-AP MLD  420  is connected to (e.g., is associated with) AP MLD  410 . For example, AP MLD  410  can use an optional message  409  (e.g., a frame) to update the backup link. In some examples, AP MLD  410  may update the backup link based on information AP MLD  410  may receive from non-AP MLD  420 . Additionally, or alternatively, AP MLD  410  may update the backup link based on information AP MLD  410  may receive from other non-AP MLDs. In some examples, AP MLD  410  may update the backup link if, for example, the quality of the current backup link deteriorates. In some examples, AP MLD  410  may update the backup link if, for example, the current backup link becomes unavailable (e.g., the current backup link becomes the new low latency link). In some examples, AP MLD  410  may update the backup link if, for example, non-AP MLD  420 ′s backup link preference charges. 
     According to some aspects, the agreed backup link (or the backup link agreement) between AP MLD  410  and non-AP MLD  420  can be applicable only to low latency traffic that is associated with certain access categories (AC) (such as but not limited voice (AC_VO), video (AC_VI), and the like) and/or certain TIDs associated with low latency traffic. However, the aspects of this disclosure are not limited to these examples and the backup link agreement can be applicable to other traffic too. In some example, the primary low latency link is also used for data communication that does not require low latency, in which case the primary low latency link functions as the primary link of data communication. 
     As discussed in more detail below, after the backup link establishment, AP MLD  410  and non-AP MLD  420  commit to be available on the backup link during specific time to assist the data communication on the primary low latency link, according to some aspects of this disclosure. 
     In some examples, messages  401 ,  403   405  and  409  are the specific frames used only for the backup link establishment. In some other examples, the information contained in these messages are piggybacked onto other frames that also serve other purposes. 
       FIGS.  5 A,  5 B, and  5 C  illustrate three exemplary backup links between an AP MLD and a non-AP MLD, according to some aspects of the disclosure.  FIG.  5 A  illustrates one example where a transceiver, which is capable of both transmitting and receiving is associated with the backup link.  FIG.  5 B  illustrates an example where a receiver, which is only capable of receiving is associated with the backup link.  FIG.  5 C  illustrates an example where a receiver, which is associated with the backup link, can be turned into a transceiver by moving radio resource from other transceiver and therefore becomes capable of both transmitting and receiving. In some examples, the AP MLD can include AP MLD  110  of  FIGS.  1 A and  1 B  and the non-AP MLD can include one of non-AP MLD  120   a - 120   c  of  FIGS.  1 A and  1 B . 
     In the non-limiting example of  FIG.  5 A , AP MLD  510  can include three transceivers  530   a - 530   c  (e.g., AP 1 -AP 3 ). For example, AP MLD  510  can include transceiver  530   a  (e.g., AP 1 ) configured to enable connection(s) and communication over a multi-link WLAN network having the first link (e.g., link  550   a ) associated with 2.4 GHz wireless communication channel. For example, AP MLD  510  can include transceiver  530   b  (e.g., AP 2 ) configured to enable connection(s) and communication over the multi-link WLAN network having a second link (e.g., link  550   b ) associated with 5 GHz wireless communication channel. For example, AP MLD  510  can include transceiver  530   c  (e.g., AP 3 ) configured to enable connection(s) and communication over the multi-link WLAN network having a third link (not shown) associated with 6 GHz wireless communication channel. 
     According to some aspects, non-AP MLD520 can include two transceivers  540   a - 540   b  (e.g., STA 1  and STA 2 ). For example, non-AP MLD  520  can include transceiver  540   a  (e.g., STA 1 ) configured to enable connection(s) and communication over a multi-link WLAN network having the first link (e.g., link  550   a ) associated with 2.4 GHz wireless communication channel. For example, non-AP MLD  520  can include transceiver  540   b  (e.g., STA 2 ) configured to enable connection(s) and communication over the multi-link WLAN network having a second link (e.g., link  550   b ) associated with 5 GHz wireless communication channel or configured to enable connection(s) and communication over the multi-link WLAN network having a third link (not shown) associated with 6 GHz wireless communication channel, where non-AP MLD  520  does not use the second link and the third link simultaneously. 
     According to some aspects, link  550   b  is the primary low latency link and link  550   a  is the backup link. For example, method  400  discussed with respect to  FIG.  4    can be used to determine and select link  550   a  as the backup link. In this example, transceiver  540   a  (e.g., STA 1 ), which is capable of both transmitting and receiving data is associated with the backup link. 
     Although  FIG.  5 A  is discussed with respect to the 5 GHz link being the primary low latency link and the 2.4 GHz link being the backup link, the aspects of this disclosure are not limited to this example and other links can be selected as primary low latency link and/or backup link. In a non-limiting example, the 2.4 GHz link can be the primary low latency link and the 6 GHz link can be the backup link. And so on. 
     In the non-limiting example of  FIG.  5 B , AP MLD  560  can include three transceivers  580   a - 580   c  (e.g., AP 1 -AP 3 ). For example, AP MLD  560  can include transceiver  580   a  (e.g., AP 1 ) configured to enable connection(s) and communication over a multi-link WLAN network having the first link (not shown) associated with 2.4 GHz wireless communication channel. For example, AP MLD  560  can include transceiver  580   b  (e.g., AP 2 ) configured to enable connection(s) and communication over the multi-link WLAN network having a second link (e.g., link  595   b ) associated with 5 GHz wireless communication channel. For example, AP MLD  560  can include transceiver  580   c  (e.g., AP 3 ) configured to enable connection(s) and communication over the multi-link WLAN network having a third link (not shown) associated with 6 GHz wireless communication channel. 
     According to some aspects, non-AP MLD  570  can include two transceivers  590   a - 590   b  (e.g., STA 1  and STA 2 ). For example, non-AP MLD  570  can include transceiver  590   a  (e.g., STA 1 ) configured to enable connection(s) and communication over a multi-link WLAN network having the first link (not shown) associated with 2.4 GHz wireless communication channel. For example, non-AP MLD  570  can include transceiver  590   b  (e.g., STA 2 ) configured to enable connection(s) and communication over the multi-link WLAN network having a second link (e.g., link  595   b ) associated with 5 GHz wireless communication channel or configured to enable connection(s) and communication over the multi-link WLAN network having a third link (not shown) associated with 6 GHz wireless communication channel, where non-AP MLD  570  does not use the second link and the third link simultaneously. 
     According to some aspects, non-AP MLD  570  can include one or more optional receiver(s)  591 . The receiver  591  can be a receive-only auxiliary radio such as, but not limited to, a scan radio. In some examples, receiver  591  can be a receive-only auxiliary radio such as, but not limited to, a receive-only radio used for non-scanning purpose(s). According to some examples, receiver  591  can be configured to receive data and/or scan channel(s) over a first link (e.g., link  592 ) associated with 2.4 GHz wireless communication link. Additionally, or alternatively, receiver  591  can be configured to receive data and/or scan channel(s) over a second link (e.g., link  595   b ) associated with 5 GHz wireless communication link. Additionally, or alternatively, receiver  591  can be configured to receive data and/or scan channel(s) over a third link (not shown) associated with 6 GHz wireless communication link. In some examples, non-AP MLD  570  can include more than one receiver  591 , each one of receivers  591  can be configured to operate at one or more wireless communication links. 
     According to some aspects, link  595   b  is the primary low latency link and link  592  is the backup link. For example, method  400  discussed with respect to  FIG.  4    can be used to determine and select link  592  as the backup link. In this example, receiver  591  (e.g., receive-only auxiliary radio such as a scan radio, a radio for non-scanning receive-only purposes, etc.), which is only capable of receiving, is associated with the backup link. 
     Although  FIG.  5 B  is discussed with respect to the 5 GHz link being the primary low latency link and the 2.4 GHz link being the backup link, the aspects of this disclosure are not limited to this example and other links can be selected as primary low latency link and/or backup link. In a non-limiting example, the 2.4 GHz link can be the primary low latency link and the 6 GHz link can be the backup link. In this example, receiver  591  can be a receive-only auxiliary radio (e.g., a scan radio) configured to operate at the 6 GHz link. In another example, the 5 GHz link can be the primary low latency link and the 6 GHz link can be the backup link. In this example, receiver  591  can be a receive-only auxiliary radio (e.g., a scan radio) configured to operate at the 6 GHz link. And so on. 
     In the non-limiting example of  FIG.  5 C , AP MLD  565  can include three transceivers  585   a - 585   c  (e.g., AP 1 -AP 3 ). For example, AP MLD  565  can include transceiver  585   a  (e.g., AP 1 ) configured to enable connection(s) and communication over a multi-link WLAN network having the first link (not shown) associated with 2.4 GHz wireless communication channel. AP MLD  565  can further include transceiver  585   b  (e.g., AP 2 ) configured to enable connection(s) and communication over the multi-link WLAN network having a second link (e.g., link  598   b ) associated with  5  GHz wireless communication channel. AP MLD  565  can further include transceiver  585   c  (e.g., AP 3 ) configured to enable connection(s) and communication over the multi-link WLAN network having a third link (not shown) associated with 6 GHz wireless communication channel. 
     According to some aspects, non-AP MLD  575  can include one transceiver  593  (e.g., STA 1 ). For example, non-AP MLD  575  can include transceiver  593  (e.g., STA 1 ) configured to enable connection(s) and communication over the multi-link WLAN network having a second link (e.g., link  598   b ) associated with 5 GHz wireless communication channel or configured to enable connection(s) and communication over the multi-link WLAN network having a third link (not shown) associated with 6 GHz wireless communication channel, where non-AP MLD  575  does not use the second link and the third link simultaneously. 
     According to some aspects, non-AP MLD  575  can include one or more optional auxiliary transceivers (or, radio(s))  594 . Auxiliary radio  594  can be a receiver-only that normally operates in a listening mode. According to some examples, auxiliary transceiver  594  can be configured to receive data over a first link (e.g., link  596 ) associated with 2.4 GHz wireless communication link. Additionally, or alternatively, auxiliary transceiver  594  can be configured to receive data over a second link (e.g., link  598   b ) associated with 5 GHz wireless communication link. Additionally, or alternatively, auxiliary transceiver  594  can be configured to receive data a third link (not shown) associated with 6 GHz wireless communication link. In some examples, non-AP MLD  575  can include more than one auxiliary transceiver  594 , each one of auxiliary transceiver  594  can be configured to operate at one or more wireless communication links. 
     According to some aspects, link  598   b  is the primary low latency link and link  596  is the backup link. For example, method  400  discussed with respect to  FIG.  4    can be used to determine and select link  596  as the backup link. In this example, auxiliary transceiver  594 , which is normally in the listening mode (e.g., receiving), is associated with the backup link. 
     According to some aspects, auxiliary transceiver  594  normally operates in a listening mode. The listening mode of operation can include clear channel assessment (CCA) and receiving special frames (e.g., special control frames, or special management frames) from AP MLD  565 . The radio resource (e.g., antennas) at non-AP MLD  575  can be shared between transceiver  593  (e.g., the main radio) and auxiliary transceiver  594  in a time-sharing fashion on demand, according to some aspects. Upon receiving a special frame (e.g., a notification frame) from AP MLD  565 , the radio resource is moved from transceiver  593  (e.g., the main radio) to auxiliary transceiver  594  so that auxiliary transceiver  594  becomes the main radio that is capable of both transmission and reception. 
     When the primary link quality (e.g., quality of primary link  598   b ) deteriorates, AP MLD  565  transmits a notification frame on backup link  596 . Upon the reception of such a notification frame on backup link  596 , the radio resource is moved from transceiver  593  to the auxiliary transceiver  594  such that auxiliary transceiver  594  becomes both transmission and reception capable (e.g., backup link  596  changes into the main communication link to carry the low latency communication.) In some aspects, the notification frame can be of either a management frame type or a control frame type. 
     Although  FIG.  5 C  is discussed with respect to the 5 GHz link being the primary low latency link and the 2.4 GHz link being the backup link, the aspects of this disclosure are not limited to this example and other links can be selected as primary low latency link and/or backup link. In a non-limiting example, the 2.4 GHz link can be the primary low latency link and the 6 GHz link can be the backup link. In this example, auxiliary transceiver  594  can be an auxiliary radio configured to operate at the 6 GHz link. In another example, the 5 GHz link can be the primary low latency link and the 6 GHz link can be the backup link. In this example, auxiliary transceiver  594  can be an auxiliary radio to operate at the 6 GHz link. And so on. 
     As noted above, each transceiver/radio  330 ,  530 ,  580 , and/or  585  can also be referred to herein as an AP. Each transceiver/radio  340 ,  540 ,  590 , and/or  593  can also be referred to herein as an STA. Additionally, or alternatively, a STA and/or an AP is associated with a specific communication link/channel. For example, a first STA (and/or a first AP) is associated with a first link associated with the 2.4 GHz wireless communication channel. A second STA (and/or a second AP) is associated with a second link associated with the 5 GHz wireless communication channel. And, a third STA (and/or a third AP) is associated with a third link associated with the 6 GHz wireless communication channel. 
       FIG.  6    illustrates one exemplary operation of a backup link enabled by a transceiver, according to some aspects of the disclosure. According to some examples, the exemplary operation of the backup link as discussed in  FIG.  6    is enabled by a transceiver at a non-AP MLD that is capable of both transmitting and receiving data, for example as discussed with respect to  FIG.  5 A . 
     According to some aspects, STA  620  is an STA of the backup link of a non-AP MLD. For example, STA  620  can be STA 1  (e.g., transceiver  540   a ) of non-AP MLD  520  of  FIG.  5 A . According to some aspects, traffic schedule  601  is the low latency traffic schedule on a primary link (e.g., primary low latency link  550   b  of  FIG.  5 A ). The non-AP MLD that includes STA  620  can be informed about traffic schedule  601  associated with an AP MLD&#39;s traffic (e.g., the data communicated between the non-AP MLD and the AP MLD). For example, the AP MLD can inform the non-AP MLD (and other non-AP MLDs) about traffic schedule  601  associated with the AP MLD&#39;s downlink (DL) low latency traffic delivered on the primary low latency link. Additionally, or alternatively, the non-AP MLD that includes STA  620  can obtain the schedule  601  of the traffic delivered on the primary low latency link from upper layers of the non-AP MLD and/or the AP MLD. In some examples, traffic schedule  601  include information about data that is being communicated between the non-AP MLD that includes STA  620  and the AP MLD. The information in traffic schedule  601  can include at least one of traffic period interval  603 , burst duration  605 , or the like. The information in traffic schedule  601  is not limited to these examples and can include other information about the traffic/data that is being communicated between the non-AP MLD and the AP MLD. 
     In this exemplary aspect, STA  620  (STA of the backup link) sets a power save schedule  611  associated with the transceiver that operates at the backup link based on traffic schedule  601 , the schedule of the uplink data transmission of STA  620 , and possibly other information. For example, as illustrated in  FIG.  5 A , link  550   a  is selected as the backup link and transceiver  540   a  (e.g., STA 1 -STA  620 ) is configured to operate at backup link  550   a.  In this example, power save schedule  611  associated with transceiver  540   a  is set based on traffic schedule  601  and possibly other factors. STA  620  sets power save schedule  611  associated with the transceiver that operates at the backup link based on traffic schedule  601  (and possibly other factors) such that STA  620  (e.g., the transceiver that operates at the backup link) is awake during the time of the AP MLD&#39;s downlink (DL) traffic deliver. For example, power save schedule  611  can include awake periods  613   a  and  613   b  and sleep or doze periods  615 . Awake periods  613  are periods where STA  620  (e.g., the transceiver that operates at the backup link) is an awake state and able to receive DL low latency data from the AP MLD (and/or is able to transmit uplink (UL) low latency data to the AP MLD) when the low latency communication occurs on the primary low latency link, according to some examples. Sleep or doze periods  615  are periods where STA  620  (e.g., the transceiver that operates at the backup link) is in a sleep or doze state of a power save mode, according to some examples. 
     As illustrated in  FIG.  6   , STA  620  sets power save schedule  611  associated with STA  620  (e.g., the transceiver that operates at the backup link) based on traffic schedule  601  and may also set power save schedule  611  based on its UL traffic schedule and possibly other factors, such that awake periods  613  encompass burst durations  605 , according to some examples. Therefore, during the time that the AP MLD transmits its DL traffic/data, STA  620  (e.g., the transceiver that operates at the backup link) is awake and able to receive the DL traffic/data if needed. By setting power save schedule  611  associated with STA  620  (e.g., the transceiver that operates at the backup link) based on traffic schedule  601 , STA  620  commits to be available on the backup link when the low latency traffic is delivered over the primary low latency link, according to some aspects of this disclosure. 
     In one example, the AP MLD and another STA of the non-AP MLD (e.g., STA 2   540   b  of  FIG.  5 A ) can communicate over the primary low latency link (e.g., link  550   b  of  FIG.  5 A ). Additionally, the AP MLD and the non-AP MLD that includes STA  620  has already established the backup link (e.g., link  550   a  of  FIG.  5 A ) as discussed, for example, with respect to  FIG.  4   , and the non-AP MLD that includes STA  620  has set power save schedule  611  associated with STA  620  (e.g., the transceiver that operates at the backup link) based on traffic schedule  601  (and may also have set power save schedule  611  based on the UL traffic schedule of STA  620  and possibly other factors). In this example, if the AP MLD determines that the quality of the primary low latency link has deteriorated, the AP MLD can first transmit a link quality deterioration and link switch notification frame to STA  620  on the backup link, then switch the traffic to the backup link (e.g., link  550   a  and use transceiver  530   a ) to continue to communicate with STA  620  using the backup link. In this example, since STA  620  has set power save schedule  611  based on traffic schedule  601 , STA  620  can receive the traffic from the AP MLD without any interruption and/or without consuming any additional channel switch time. In some example, the new link to continue the low latency communication is another link indicated in the notification frame that is different from the backup link. In some examples, the data communication is switched between the primary low latency link and the backup link for other reasons, even when the link quality of the primary low latency link does not deteriorate. 
       FIG.  7    illustrates another exemplary operation of a backup link enabled by a transceiver, according to some aspects of the disclosure. According to some examples, the exemplary operation of the backup link as discussed in  FIG.  7    is enabled by a transceiver at a non-AP MLD that is capable of both transmitting and receiving data, for example as discussed with respect to  FIG.  5 A . 
       FIG.  7    illustrates an exemplary power save schedule  701  of STA  740   b  of a primary low latency link of a non-AP MLD. In other words, STA  740   b  is an STA of the non-AP MLD that operates at the primary low latency link (e.g., transceiver  540   b  (STA 2 ) operating on link  550   b  of  FIG.  5 A ).  FIG.  7    also illustrates exemplary power save schedule  711  of STA  740   a  of a backup link of the non-AP MLD. In other words, STA  740   a  is an STA of the non-AP MLD that operates at the backup link (e.g., transceiver  540   a  (STA 1 ) operating on link  550   a  of  FIG.  5 A ). According to some aspects, STA  740   b  can establish a power save agreement with the AP (e.g., AP 2  of  FIG.  5 A ) on the primary low latency link (e.g., link  550   b  of  FIG.  5 A ). In one example, the power save agreement can include a Target Wake Time (TWT) agreement. However, the aspects of this disclosure are not limited to TWT agreement and can include other power save agreements between the STA and AP (and/or between STAs and/or between APs). In some examples, STA  740   b  and the AP can establish the power save agreement during the initial link setup between the AP MLD (that includes the AP) and the non-AP MLD (that includes STAs  740   a  and  740   b ). For example, the power save agreement establishment can be performed during an association operation (e.g., using association request and/or association response). Additionally, or alternatively, the power save agreement establishment can be negotiated after the initial link setup. However, the aspects of this disclosure are not limited to these examples and other methods can be used to establish the power save agreement for the primary low latency link. 
     In some examples, the power save agreement for the primary low latency link can include power save schedule  701 . For example, power save schedule  701  can include one or more awake periods  703   a  and  703   b  and one or more sleep or doze periods  705 . Awake periods  703  are periods where STA  740   b  (e.g., the transceiver that operates at the primary low latency link) is an awake state and able to receive DL data from the AP (and is able to transmit uplink (UL) data to the AP), according to some examples. Sleep or doze periods  705  are periods where STA  740   b  (e.g., the transceiver that operates at the primary low latency link) is in a sleep or doze state of a power save mode, according to some examples. 
     In some examples, STA  740   a  (or the non-AP MLD that includes STA  740   b ) sets power save schedule  711  of STA  740   a  (e.g., transceiver  540   a  on link  550   a  of  FIG.  5 A ) based on power save schedule  701  of STA  740   b  (e.g., the transceiver configured to operate at the primary low latency link for example, transceiver  540   b  on link  550   b ) and possibly some other factors. Power save schedule  711  of the STA  740   a  (e.g., transceiver  540   a  on link  550   a  of  FIG.  5 A ) can include awake periods  713   a  and  713   b  and sleep or doze periods  715 . Awake periods  713  are periods where STA  740   a  (e.g., the transceiver that operates at the backup link) is in an awake state and able to receive DL data from the AP (and is able to transmit uplink (UL) data to the AP) when the low latency communication occurs on the primary low latency link, according to some examples. Sleep or doze periods  715  are periods where STA  740   a  (e.g., the transceiver that operates at the backup link) is in a sleep or doze state of a power save mode, according to some examples. 
     According to some aspects, setting power save schedule  711  of STA  740   a  (e.g., the transceiver configured to operate at the backup link for example, transceiver  540   a  on link  550   a  of  FIG.  5 A ) based on power save schedule  701  of STA  740   b  (e.g., the transceiver configured to operate at the primary low latency link for example, transceiver  540   b  on link  550   b  of  FIG.  5 A ) and based on possibly some other factors can include setting the awake periods ( 703  and  713 ) to have the same or substantially the same duration and to setting the awake periods ( 703  and  713 ) to start at the same or substantially the same time. Additionally, or alternatively, setting power save schedule  711  of STA  740   a  (e.g., the transceiver configured to operate at the backup link for example, transceiver  540   a  on link  550   a  of  FIG.  5 A ) based on power save schedule  701  of STA  740   b  (e.g., the transceiver configured to operate at the primary low latency link for example, transceiver  540   b  on link  550   b  of  FIG.  5 A ) and based on possibly some other factors can include setting the sleep/doze periods ( 705  and  715 ) to have the same or substantially the same duration and to setting the sleep/doze periods ( 705  and  715 ) to start at the same or substantially the same time. 
     In some examples, setting power save schedule  711  of STA  740   a  (e.g., the transceiver configured to operate at the backup link for example, transceiver  540   a  on link  550   a  of  FIG.  5 A ) based on power save schedule  701  of STA  740   b  (e.g., the transceiver configured to operate at the primary low latency link for example, transceiver  540   b  on link  550   b  of  FIG.  5 A ) can include setting awake periods  713  of power save schedule  711  to encompass awake periods  703  of power save schedule  701 . 
     Therefore, during the time that STA  740   b  (e.g., the transceiver that operates at the primary low latency link) is in the awake state, STA  740   a  (e.g., the transceiver that operates at the backup link) is also at the awake state and is able to receive a notification and the DL traffic/data if needed. By setting power save schedule  711  of STA  740   a  (e.g., the transceiver configured to operate at the backup link for example, transceiver  540   a  on link  550   a  of  FIG.  5 A ) based on power save schedule  701  of STA  740   b  (e.g., the transceiver configured to operate at the primary low latency link for example, transceiver  540   b  on link  550   b  of  FIG.  5 A ), STA  740   a  commits to be available on the backup link when STA  740   b  is awake on the primary low latency link, according to some aspects of this disclosure. 
     In one example, the AP MLD and STA  740   b  can communicate over the primary low latency link (e.g., link  550   b  of  FIG.  5 A ). Additionally, the AP MLD and STA  740   a  has already established the backup link (e.g., link  550   a  of  FIG.  5 A ) as discussed, for example, with respect to  FIG.  4   , and the non-AP MLD that includes STAs  740   a  and  740   b  has set power save schedule  711  associated with STA  740   a  (e.g., the transceiver that operates at the backup link) based on power save schedule  701  associated with STA  740   b  (e.g., the transceiver that operates at the primary low latency link). In this example, if the AP MLD determines that the quality of the primary low latency link has deteriorated, the AP MLD can first transmit a link quality deterioration and link switch notification frame to STA  740   a  on the backup link, then switch the traffic to the backup link (e.g., link  550   a  and use transceiver  530   a ) to continue to communicate (e.g., transmit DL traffic) with the non-AP MLD that includes STAs  740   a  and  740   b  using the backup link. In this example, since the non-AP MLD that includes STAs  740   a  and  740   b  has set power save schedule  711  associated with STA  740   a  (e.g., the transceiver that operates at the backup link) based on power save schedule  701  associated with STA  740   b  (e.g., the transceiver that operates at the primary low latency link), the non-AP MLD can receive the notification frame and traffic from the AP MLD without any interruption and/or without consuming any additional channel switch time. In some example, the new link to continue the low latency communication is another link indicated in the notification frame that is different from the backup link. In some examples, the data communication is switched between the primary low latency link and the backup link for other reasons, even when the link quality of the primary low latency link does not deteriorate. 
       FIG.  8    illustrates one exemplary operation of a backup link enabled by a receiver, according to some aspects of the disclosure. According to some examples, the exemplary operation of the backup link as discussed in  FIG.  8    is enabled by a receiver at a non-AP MLD that is capable of receiving data, for example, as discussed with respect to  FIG.  5 B . In some examples, the receiver is a scan radio capable of only receiving data. 
     According to some aspects, scan radio  820  is a receive-only auxiliary radio of the backup link of a non-AP MLD. For example, scan radio  820  can be receive-only auxiliary radio  591  of non-AP MLD  570  of  FIG.  5 B . Although radio  820  is discussed with respect to a scan radio, radio  820  can include other receive-only auxiliary radios. According to some aspects, traffic schedule  801  is the low latency traffic schedule on a primary link (e.g., primary low latency link  595   b  of  FIG.  5 B ). The non-AP MLD that includes scan radio  820  can be informed about traffic schedule  801  associated with an AP MLD&#39;s traffic (e.g., the data communicated between the non-AP MLD and the AP MLD). For example, the AP MLD can inform the non-AP MLD that includes scan radio  820  about traffic schedule  801  associated with the AP MLD&#39;s downlink (DL) low latency traffic. Additionally, or alternatively, the non-AP MLD can obtain the traffic schedule  801  from upper layers of the non-AP MLD and/or the AP MLD. In some examples, traffic schedule  801  includes information about data that is being communicated between the non-AP MLD and the AP MLD. The information in traffic schedule  801  can include at least one of traffic period interval  803 , burst duration  805 , or the like. The information in traffic schedule  801  is not limited to these examples and can include other information about the traffic/data that is being communicated between the non-AP MLD and the AP MLD. 
     In this exemplary aspect, where the non-AP MLD enables the backup link using scan radio  820 , which is a receiver that is a scan radio, the non-AP MLD sets a scan schedule  811  associated with scan radio  820  (e.g., the receive-only auxiliary receiver for example receiver  591  of  FIG.  5 B ) based on traffic schedule  801 . For example, as illustrated in  FIG.  5 B , link  592  is selected as the backup link and receiver  591  is configured to operate at backup link  592  during the dwell phase  817  and/or scan the channels in the network during the scan phase  815 . In this example, scan schedule  811  associated with receiver  591  is set based on traffic schedule  801 . 
     According to some examples, scan schedule  811  can have scan interval  813 , which can include scan phase  815  and dwell phase  817 . In some examples, scan phase  815  includes a phase (e.g., a time period) where scan radio  820  (e.g., the receive-only auxiliary receiver for example, a scan radio such as receiver  591  of  FIG.  5 B ) is configured to scan through channel(s) to collect network statistics. For example, during scan phase  815 , scan radio  820  can listen for per channel and/or obtain statistics indicating a corresponding channel quality. Scan phase  815  can repeat in each scan interval  811 . In some examples, each scan phase  815  can include one or more time periods. At each of the one or more time periods, scan radio  820  can scan a channel within, for example, the 2.4 GHz link, the 5 GHz link, and/or the 6 GHz link. In a non-limiting example, the 2.4 GHz link can include 11 channels and scan phase  815  can include 11 time periods. Each one of the 11 time periods can be used to scan the corresponding channels within the 2.4 GHz link. However, the aspects of this disclosure are not limited to this example, and scan phase  815  can be used for other frequency bands/links. In some examples, during the scan phase  815 , scan radio  820  listens to the channel and obtains statistics indicating the corresponding channel quality. The statistics can include, but are not limited to, channel busy time, channel load, and the like. 
     In some examples, dwell phase  817  can include a phase (e.g., a time period) where the receive-only receiver can be available to receive notification frame(s) from the AP MLD on the backup link if needed. In other words, during dwell phase  817 , scan radio  820  (e.g., receiver  591  of  FIG.  5 B ) does not perform the scan function and can be “parked” at the backup link (e.g., link  592  of  FIG.  5 B ) to assist with the primary low latency link (e.g. link  595   b  of FIG.  5 B). For example, during dwell phase  817 , scan radio  820  (e.g., receiver  591  of  FIG.  5 B ) is in an awake state and configured to receive the notification frame on the backup link (e.g., link  592  of  FIG.  5 B ) if needed. Dwell phase  817  can occur in each scan interval  811 . 
     Scan radio  820  and/or the non-AP MLD that includes scan radio  820  sets scan schedule  811  associated with scan radio  820  (e.g., the receive-only receiver such as the scan radio) that operates at the backup link based on traffic schedule  801  such that scan radio  820  is awake and configured to receive the notification frame on the backup link if needed, during the time of the low latency communication on the primary low latency link. As illustrated in  FIG.  8   , the non-AP MLD and/or scan radio  820  sets scan schedule  811  associated with scan radio  820  based on traffic schedule  801  such that dwell phase  817  encompass burst durations  805 , according to some examples. Therefore, during the times  805  that AP MLD transmits its DL traffic/data on the primary low latency link, scan radio  820  is able to receive notification frames if needed. By setting scan schedule  811  associated with scan radio  820  based on traffic schedule  801 , scan radio  820  commits to be available on the backup link during the time of low latency communication on the primary low latency link, according to some aspects of this disclosure. 
     In one example, the AP MLD and the non-AP MLD that includes scan radio  820  can communicate over the primary low latency link (e.g., link  595   b  of  FIG.  5 B ). Additionally, the AP MLD and the non-AP MLD has already established the backup link (e.g., link  592  of  FIG.  5 B ) as discussed, for example, with respect to  FIG.  4   . Additionally, or alternatively, the non-AP MLD has informed the AP MLD that the backup link (e.g., link  592  of  FIG.  5 B ) corresponds to scan radio  820  (e.g., a receive-only auxiliary receiver  591  of  FIG.  5 B  such as a scan radio) and its capability (e.g., the type of frames the scan radio  820  is capable of receiving), as discussed, for example, with respect to  FIG.  4   . Also, the non-AP MLD and/or scan radio  820  has set scan schedule  811  associated with scan radio  820  based on traffic schedule  801 . According to some examples, if the AP MLD determines that the quality of the primary low latency link has deteriorated, the AP MLD can transmit a notification frame to scan radio  820  using the backup link. The non-AP MLD can receive the notification frame on scan radio (e.g., the receive-only auxiliary receiver). In some examples, the notification frame can include a link quality change and link switch notification frame, which informs the non-AP MLD that the quality of the primary low latency link has deteriorated and informs the non-AP MLD of a new link to be used as the new low latency communication link to continue the communication. In one example, as illustrated in  FIG.  5 B , the new low latency link can be the 6 GHz link between transceiver  580   c  of AP MLD  560  and transceiver  590   b  of non-AP MLD  570 . However, the aspects of this disclosure are not limited to these examples, and other combination of links can be used as the primary low latency link, the backup link, and the new low latency link. 
     After receiving the notification frame, the non-AP MLD can switch to the new low latency link to continue the low latency communication between the AP MLD and the non-AP MLD . In this example, since the non-AP MLD has set scan schedule  811  associated with scan radio  820  based on traffic schedule  801 , scan radio  820  can receive the notification frame from the AP MLD without any interruption and/or without consuming any additional channel switch time. In some examples, the scan radio is capable of receiving the DL data frames and sending an acknowledge frame to a received DL data frame, so that the backup link can receive the DL traffic in addition to receiving the notification frame. 
     In some examples, within non-AP MLD  570 , the link  592  is enabled by a receiver that is not a scan radio, where such a receiver needs to be available to receive packet when the low latency traffic are delivered at the primary low latency link. When the link quality deteriorates on the primary low latency link, the AP MLD transmits a notification on link quality deterioration and the information on the new link to switch to in order to continue the low latency communication. 
       FIG.  9    illustrates another exemplary operation of a backup link enabled by a receiver, according to some aspects of the disclosure. According to some examples, the exemplary operation of the backup link as discussed in  FIG.  9    is enabled by a receiver at a non-AP MLD that is capable of receiving data, for example, as discussed with respect to  FIG.  5 B . In some examples, the receiver is a scan radio capable of only receiving data. 
       FIG.  9    illustrates an exemplary power save schedule  901  of STA  990  of a primary low latency link of a non-AP MLD. In other words, STA  990  is an STA of the non-AP MLD that operates at the primary low latency link (e.g., link  595   b  of  FIG.  5 B ). According to some aspects, STA  990  can establish a power save agreement with the AP on the primary low latency link (e.g., link  595   b  of  FIG.  5 B ). In one example, the power save agreement can include a Target Wake Time (TWT) agreement. However, the aspects of this disclosure are not limited to TWT agreement and can include other power save agreements between the STA and the AP (and/or between STAs and/or between APs). In some examples, the non-AP MLD that includes STA  990  and the AP MLD can establish the power save agreement during the initial link setup between the AP MLD and the non-AP MLD . For example, the power save agreement establishment can be performed during an association operation (e.g., using association request and/or association response). Additionally, or alternatively, the power save agreement establishment can be negotiated after the initial link setup. However, the aspects of this disclosure are not limited to these examples and other methods can be used to establish the power save agreement for the primary low latency link. 
     In some examples, the power save agreement for the primary low latency link can include power save schedule  901 . For example, power save schedule  901  can include one or more awake period(s)  903  and one or more sleep or doze period(s)  905 . Awake periods  903  are periods where the transceiver that operates at the primary low latency link is an awake state and able to receive DL data from the AP MLD (and is able to transmit uplink (UL) data to the AP MLD), according to some examples. Sleep or doze periods  905  are periods where the transceiver that operates at the primary low latency link is in a sleep or doze state of a power save mode, according to some examples. In some examples, the power save schedule  901  are established based on the traffic schedule and other information. 
     In this exemplary aspect, where the non-AP MLD that includes STA  990  enables the backup link using a receiver such as scan radio  991 , the non-AP MLD sets a scan schedule  911  associated with scan radio  991  (e.g., a receive-only auxiliary receiver such as receiver  591  of  FIG.  5 B ) based on power save schedule  901 . For example, as illustrated in  FIG.  5 B , link  592  is selected as the backup link and receiver  591  is configured to operate at backup link  592  during the dwell phase  917  and/or scan the channel in the network during the scan phase  915 . In this example, scan schedule  911  associated with receiver  591  is set based on power save schedule  901 . According to some aspects, scan radio  991  is a receive-only auxiliary radio of the backup link of a non-AP MLD. For example, scan radio  991  can be receive-only auxiliary radio  591  of non-AP MLD  570  of  FIG.  5 B . Although radio  991  is discussed with respect to a scan radio, radio  991  can include other receive-only auxiliary radios. 
     According to some examples, scan schedule  911  can have scan interval  913 , which can include scan phase  915  and dwell phase  917 . In some examples, scan phase  915  includes a phase (e.g., a time period) where scan radio  991  (e.g., the receive-only auxiliary receiver (e.g., a scan radio) such as receiver  591  of  FIG.  5 B ) is configured to scan through channel(s). For example, during scan phase  915 , scan radio  991  can listen for per channel and/or obtain statistics indicating a corresponding channel quality. Scan phase  915  can occur in each scan interval  911 . Scan phase  915  is similar to scan phase  815  discussed above with respect to  FIG.  8   . 
     In some examples, dwell phase  917  can include a phase (e.g., a time period) where scan radio  991  can be available to receive notification frame(s) from the AP MLD on the backup link. In other words, during dwell phase  917 , scan radio  991  (e.g., receiver  591  of  FIG.  5 B ) can be “parked” at the backup link (e.g., link  592  of  FIG.  5 B ) to assist with the primary low latency link (e.g. link  595   b  of  FIG.  5 B ). For example, during dwell phase  917 , scan radio  991  (e.g., receiver  591  of  FIG.  5 B ) can be configured to receive the notification frame on the backup link (e.g., link  592  of  FIG.  5 B ). Dwell phase  917  can occur in each scan interval  911 . 
     According to some aspects, setting scan schedule  911  of scan radio  991  (e.g., receive-only auxiliary receiver  591  of  FIG.  5 B ) based on power save schedule  901  of STA  990  (e.g., the transceiver configured to operate at the primary low latency link such as transceiver  590   b  on link  595   b  of  FIG.  5 B ) can include setting dwell phase  917  to have the same or substantially the same duration as awake period  903  and/or setting dwell phase  917  to start at the same or substantially the same time as awake period  903 . Additionally, or alternatively, setting scan schedule  911  of scan radio  991  (e.g., receive-only auxiliary receiver  591  of  FIG.  5 B ) based on power save schedule  901  of STA  990  (e.g., the transceiver configured to operate at the primary low latency link such as transceiver  590   b  on link  595   b  of  FIG.  5 B ) can include setting scan phase  915  to have the same or substantially the same duration as sleep/doze period  905  and/or setting scan phase  915  to start at the same or substantially the same time as sleep/doze period  905 . 
     In some examples, setting scan schedule  911  of scan radio  991  (e.g., receive-only auxiliary receiver  591  of  FIG.  5 B ) based on power save schedule  901  of STA  990  (e.g., the transceiver configured to operate at the primary low latency link such as transceiver  590   b  on link  595   b  of  FIG.  5 B ) can include setting dwell phase  917  of scan schedule  911  to encompass awake period  903  of power save schedule  901 . 
     Therefore, during the time that STA  990  (e.g., the transceiver that operates at the primary low latency link) is in the awake state, scan radio  991  (e.g., the receive-only auxiliary receiver) is awake and able to receive the notification frame(s) on the backup link if needed. By setting scan schedule  911  associated with scan radio  991  based on power save schedule  901 , scan radio  991  commits to be available on the backup link when STA  990  is awake on the primary link, according to some aspects of this disclosure. 
     In one example, the AP MLD and STA  991  can communicate over the primary low latency link (e.g., link  595   b  of  FIG.  5 B ). Additionally, the AP MLD and the non-AP MLD that includes STA  990  and scan radio  991  has already established the backup link (e.g., link  592  of  FIG.  5 B ) as discussed, for example, with respect to  FIG.  4   . Additionally, or alternatively, the non-AP MLD has informed the AP MLD that the backup link (e.g., link  592  of  FIG.  5 B ) corresponds to scan radio  991  (e.g., a receive-only auxiliary receiver  591  of  FIG.  5 B  such as a scan radio) and its capability (e.g., the type of frames the scan radio  820  is capable of receiving), as discussed, for example, with respect to  FIG.  4   . Also, the non-AP MLD has set scan schedule  911  associated with scan radio  991  based on power save schedule  901 . According to some examples, if the AP MLD determines that the quality of the primary low latency link has deteriorated, the AP MLD can transmit a notification frame to scan radio  991  using the backup link. The non-AP MLD can receive the notification frame on scan radio  991  (e.g., the receive-only auxiliary receiver). In some examples, the notification frame can include a link quality change and link switch notification frame, which informs the non-AP MLD that the quality of the primary low latency link has deteriorated and informs the non-AP MLD of a new link to be used as the new low latency communication link to continue the communication. In one example, as illustrated in  FIG.  5 B , the new low latency link can be the 6 GHz link between transceiver  580   c  of AP MLD  560  and transceiver  590   b  of non-AP MLD  570 . However, the aspects of this disclosure are not limited to these examples, and other combination of links can be used as the primary low latency link, the backup link, and the new low latency link. 
     After receiving the notification frame, the non-AP MLD that includes STA  991  and scan radio  991  can switch to the new low latency link to continue the low latency communication between the AP MLD and the non-AP MLD . In this example, since the non-AP MLD has set scan schedule  911  associated with scan radio  991  based on power save schedule  901 , the non-AP MLD can receive the notification frame on scan radio  991  from the AP MLD without any interruption and/or without consuming any channel switch time. In some examples, the scan radio is capable of receiving the DL data frames and sending an acknowledge frame to a received DL data frame, so that the backup link can receive the DL traffic in addition to receiving the notification frame. 
     In some examples, within non-AP MLD  570 , the link  592  is enabled by a receiver that is not a scan radio, where such a receiver needs to be available to receive packet when the low latency traffic are delivered at the primary low latency link. When the link quality deteriorates on the primary low latency link, the AP MLD transmits a notification on link quality deterioration and/or the information on the new link to switch to in order to continue the low latency communication. 
       FIG.  10    illustrates an example method  1000  for a wireless system supporting and implementing backup link establishment and operation for multi-link wireless communication networks such as a wireless local area network (WLAN), according to some aspects of the disclosure. As a convenience and not a limitation,  FIG.  10    may be described with regard to elements of  FIGS.  1 - 9   . Method  1000  may represent the operation of an electronic device (e.g., a non-AP MLD as discussed in this disclosure) implementing backup link establishment and operation for multi-link wireless communication networks. Method  1000  may also be performed by system  200  of  FIG.  2    and/or computer system  1200  of  FIG.  12   . But method  1000  is not limited to the specific aspects depicted in those figures and other systems may be used to perform the method as will be understood by those skilled in the art. It is to be appreciated that not all operations may be needed, and the operations may not be performed in the same order as shown in  FIG.  10   . 
     At  1002 , a message is received, where the message can include information associated with a backup link of a wireless network. For example, a first electronic device (e.g., a non-AP MLD) can receive the message from a second electronic device (e.g., an AP MLD). In some examples, the message can include message  401  of  FIG.  4   . According to some aspects,  1002  can be part of the operation  400  of  FIG.  4    for establishing the backup link between the non-AP MLD and the AP MLD. Step  1002  can further include transmitting, to the second electronic device (e.g., the AP MLD), a second message (e.g., message  403  of  FIG.  4   ). In some examples, the second message can indicate that the first electronic device (e.g., the non-AP MLD) supports the backup link and the backup link is associated with a receiver (e.g., a receive-only receiver such as a scan radio) of the first electronic device (e.g., the non-AP MLD) or is associated with a transceiver of the first electronic device (e.g., the non-AP MLD) and other capability information relating to the backup link of the first electronic device. 
     Alternatively, step  1002  can further include transmitting, to the second electronic device (e.g., the AP MLD), a second message (e.g., message  403  of  FIG.  4   ) indicating an alternative preferred backup link. Step  1002  can further include receiving, from the second electronic device (e.g., the AP MLD), a third message (e.g., message  405  of  FIG.  4   ) confirming the updated backup link. 
     At  1004 , the first electronic device (e.g., the non-AP MLD) receives data from the second electronic device (e.g., the AP MLD) on a primary link of the wireless network. In some examples, after the backup link is established between the non-AP MLD and the AP MLD, the non-AP MLD and the AP MLD can communicate using the primary link. For example, the AP MLD and the non-AP MLD can use the primary link to communicate low latency traffic. The data can be part of a data traffic such as, but not limited to, a low latency traffic. According to some examples, the primary link is independent and separate from the backup link. 
     At  1006 , in response to a quality of the primary link being below a threshold, the first electronic device (e.g., the non-AP MLD) receives a notification frame from the second electronic device (e.g., the AP MLD) on the backup link, and additional data frame from the second electronic device on the backup link if the first device uses a transceiver (e.g., the operation in  FIG.  5 A ), or an auxiliary receiver-only radio, which can be turned to a transceiver by moving the radio resource associated the primary link to the auxiliary radio (e.g., the operation illustrated in  FIG.  5 C ), to enable the backup link, where the first and second devices switch the low latency communication to the backup link, or to continue the low latency communication another link informed/indicated by the notification frame. 
     According to some examples, the first electronic device (e.g., the non-AP MLD) has a first transceiver that is configured to operate at the primary link (e.g., configured to operate on a frequency of the primary link) and has a second transceiver that is configured to operate at the backup link (e.g., configured to operate on a frequency of the backup link). In these examples, receiving the data of the data traffic from the second electronic device (e.g., the AP MLD) on the primary link includes receiving the data using the first transceiver on the primary link. Also, receiving the additional data of the data traffic from the second electronic device (e.g., the AP MLD) on the backup link includes receiving the additional data, using the second transceiver, on the backup link or another link informed/indicated by the notification frame. According to some examples, the first and second transceivers can operate independently and separately from each other. 
     According to some examples, method  1000  can also include setting a power save schedule of the second transceiver configured to operate at the backup link based on a traffic schedule associated with the schedule of data/data traffic on the primary link and possibly other factors, so that the second device can receive the notification frame and the data/traffic frame from the first device on the backup link during the exchange of the data/traffic on the primary low latency link. Additionally, or alternatively, method  1000  can include setting a power save schedule of the second transceiver configured to operate at the backup link based on a power save schedule of the first transceiver configured to operate at the primary link and possibly other factors so that second device can receive the notification frame and data/traffic frame from the first device on the backup link during the exchange of the data/traffic on the primary low latency link. 
     According to some examples, the first electronic device (e.g., the non-AP MLD) has a transceiver that is configured to operate at the primary link (e.g., configured to operate on a frequency of the primary link) and has a receiver (e.g., a receive-only auxiliary receiver) configured to scan the backup link (e.g., the operation illustrated in  FIG.  5 B ). In these examples, receiving the data from the second electronic device (e.g., the AP MLD) on the primary link can include receiving the data, using the transceiver, on the primary link. Also, receiving the notification frame from the second electronic device on the backup link can include receiving the notification frame, using the receiver, on the backup link. According to some examples, the notification frame can include at least one of a notification that the quality of the primary link is below the threshold or information associated with a communication link to be used to continue data communication. 
     According to some examples, when the first device enables the backup link using a scan radio, method  1000  can also include setting a scan schedule of the receiver based on a traffic schedule associated with the data. Additionally, or alternatively, method  1000  can include setting a scan schedule of the receiver based on a power save schedule of the transceiver configured to operate at the primary link. 
       FIG.  11    illustrates an example method  1100  for a wireless system supporting and implementing backup link establishment and operation for multi-link wireless communication networks such as a wireless local area network (WLAN), according to some aspects of the disclosure. As a convenience and not a limitation,  FIG.  11    may be described with regard to elements of  FIGS.  1 - 9   . Method  1100  may represent the operation of an electronic device (e.g., an AP MLD as discussed in this disclosure) implementing backup link establishment and operation for multi-link wireless communication networks. Method  1100  may also be performed by system  200  of  FIG.  2    and/or computer system  1200  of  FIG.  12   . But method  1100  is not limited to the specific aspects depicted in those figures and other systems may be used to perform the method as will be understood by those skilled in the art. It is to be appreciated that not all operations may be needed, and the operations may not be performed in the same order as shown in  FIG.  11     
     At  1102 , a message is transmitted, where the message includes information associated with a backup link of a wireless network. For example, a first electronic device (e.g., an AP MLD) transmits the message to a second electronic device (e.g., a non-AP MLD). In some examples, the message can include message  401  of  FIG.  4   . According to some aspects,  1102  can be part of the operation  400  of  FIG.  4    for establishing the backup link between the non-AP MLD and the AP MLD. Step  1102  can further include receiving, from the second electronic device (e.g., the non-AP MLD), a second message (e.g., message  403  of  FIG.  4   ). In some examples, the second message can indicate that the second electronic device (e.g., the non-AP MLD) supports the backup link and the backup link is associated with a receiver (e.g., a receive-only auxiliary receiver such as a scan radio) of the second electronic device (e.g., the non-AP MLD) or is associated with a transceiver of the second electronic device (e.g., the non-AP MLD) and other capability information relating to the backup link of the second electronic device. 
     Alternatively, step  1102  can further include receiving, from the second electronic device (e.g., the non-AP MLD), a second message (e.g., message  403  of  FIG.  4   ) indicating an alternative preferred backup link. Step  1102  can further include transmitting, to the second electronic device (e.g., the non-AP MLD), a third message (e.g., message  405  of  FIG.  4   ) confirming the updated backup link. 
     At  1104 , the first electronic device (e.g., the AP MLD) transmits data to the second electronic device (e.g., the non-AP MLD) on a primary link of the wireless network. In some examples, after the backup link is established between the non-AP MLD and the AP MLD, the non-AP MLD and the AP MLD can communicate using the primary link. For example, the AP MLD and the non-AP MLD can use the primary link to communicate low latency traffic. The data can be part of a data traffic such as, but not limited to, a low latency traffic. According to some examples, the primary link is independent and separate from the backup link. 
     At  1106 , a determination is made whether the quality of the primary link has deteriorated. For example, the first electronic device (e.g., the AP MLD) can determine whether one or more metrics used to determine the quality of the link are below one or more predetermined thresholds. In some examples, the first electronic device (e.g., the AP MLD) receives information associated with the primary link from the second electronic device (and/or other electronic devices) and determines whether the quality of the primary link is below a threshold. 
     At  1108 , in response to the quality of the primary link being below the threshold, the first electronic device (e.g., the AP MLD) transmits a notification frame to the second electronic device on the backup link, and if the second device (e.g., the non-AP MLD) uses a transceiver to enable the backup link, the first and second devices switch the low latency communication to the backup link, or another link informed by the notification frame, from the primary low latency link. 
     According to some examples,  1108  can further include determining, in addition to transmitting a notification frame to the second electronic device on the backup link, whether to transmit the data to the second electronic device (e.g., the non-AP MLD) on the backup link. For example, the first electronic device (e.g., the AP MLD) can determine whether the backup link is associated with a transceiver at the second electronic device (e.g., the non-AP MLD) or with a receiver (e.g., a receive-only auxiliary receiver) at the second electronic device (e.g., the non-AP MLD) (e.g., the operation illustrated in  FIG.  5 A ), or a receiver, which can be turned into a transceiver by moving radio resource from the transceiver associated with the primary link to the receiver (e.g., the operation illustrated in  FIG.  5 C ), at the second electronic device. The first electronic device (e.g., the AP MLD) can make the determination based on the information previously transmitted by the second electronic device (e.g., the non-AP MLD) using, for example, message  403  of  FIG.  4   . If the first electronic device (e.g., the AP MLD) determines that the backup link is associated with a transceiver or a receiver that can be turned into a transceiver at the second electronic device (e.g., the non-AP MLD), the first electronic device (e.g., the AP MLD) elects the backup link as the new link for continued communication and continues the transmission of data (e.g., additional data of the data traffic) on the backup link. 
     If the first electronic device (e.g., the AP MLD) determines the backup link is associated with a receiver (e.g., a receive-only auxiliary receiver) at the second electronic device (e.g., the non-AP MLD) (e.g., the operation illustrated in  FIG.  5 B ), the first electronic device (e.g., the AP MLD) transmits the notification frame to the second electronic device (e.g., the non-AP MLD) on the backup link. According to some examples, the notification frame can include at least one of a notification that the quality of the primary link is below the threshold or information associated with a communication link (which is not the backup link) to be used for to continue communicating the data. After transmitting the notification frame, the first electronic device (e.g., the AP MLD) can continue transmitting the data on the communication link that was identified in the frame message, according to some examples. 
     Although some aspects of this disclosure are discussed with respect to low latency traffic and a primary low latency link (e.g., a link used for communicating low latency traffic), the aspects of this disclosure are not limited to these examples and can be applied to other traffics and primary links. Additionally, although some examples are provided with respect to communication between an AP MLD and a non-AP MLD, the of this disclosure are not limited to these examples and can be applied to, for example, peer-to-peer (P2P) communication too. 
     Various aspects can be implemented, for example, using one or more computer systems, such as computer system  1200  shown in  FIG.  12   . Computer system  1200  can be any well-known computer capable of performing the functions described herein such as devices  110 ,  120  of  FIGS.  1 A and  1 B , or  200  of  FIG.  2   . Computer system  1200  includes one or more processors (also called central processing units, or CPUs), such as a processor  1204 . Processor  1204  is connected to a communication infrastructure  1206  (e.g., a bus.) Computer system  1200  also includes user input/output device(s)  1203 , such as monitors, keyboards, pointing devices, etc., that communicate with communication infrastructure  1206  through user input/output interface(s)  1202 . Computer system  1200  also includes a main or primary memory  1208 , such as random access memory (RAM). Main memory  1208  may include one or more levels of cache. Main memory  1208  has stored therein control logic (e.g., computer software) and/or data. 
     Computer system  1200  may also include one or more secondary storage devices or memory  1210 . Secondary memory  1210  may include, for example, a hard disk drive  1212  and/or a removable storage device or drive  1214 . Removable storage drive  1214  may be a floppy disk drive, a magnetic tape drive, a compact disk drive, an optical storage device, tape backup device, and/or any other storage device/drive. 
     Removable storage drive  1214  may interact with a removable storage unit  1218 . Removable storage unit  1218  includes a computer usable or readable storage device having stored thereon computer software (control logic) and/or data. Removable storage unit  1218  may be a floppy disk, magnetic tape, compact disk, DVD, optical storage disk, and/any other computer data storage device. Removable storage drive  1214  reads from and/or writes to removable storage unit  1218  in a well-known manner. 
     According to some aspects, secondary memory  1210  may include other means, instrumentalities or other approaches for allowing computer programs and/or other instructions and/or data to be accessed by computer system  1200 . Such means, instrumentalities or other approaches may include, for example, a removable storage unit  1222  and an interface  1220 . Examples of the removable storage unit  1222  and the interface  1220  may include a program cartridge and cartridge interface (such as that found in video game devices), a removable memory chip (such as an EPROM or PROM) and associated socket, a memory stick and USB port, a memory card and associated memory card slot, and/or any other removable storage unit and associated interface. 
     Computer system  1200  may further include a communication or network interface  1224 . Communication interface  1224  enables computer system  1200  to communicate and interact with any combination of remote devices, remote networks, remote entities, etc. (individually and collectively referenced by reference number  1228 ). For example, communication interface  1224  may allow computer system  1200  to communicate with remote devices  1228  over communications path  1226 , which may be wired and/or wireless, and which may include any combination of LANs, WANs, the Internet, etc. Control logic and/or data may be transmitted to and from computer system  1200  via communication path  1226 . 
     The operations in the preceding aspects can be implemented in a wide variety of configurations and architectures. Therefore, some or all of the operations in the preceding aspects may be performed in hardware, in software or both. In some aspects, a tangible, non-transitory apparatus or article of manufacture includes a tangible, non-transitory computer useable or readable medium having control logic (software) stored thereon is also referred to herein as a computer program product or program storage device. This includes, but is not limited to, computer system  1200 , main memory  1208 , secondary memory  1210  and removable storage units  1218  and  1222 , as well as tangible articles of manufacture embodying any combination of the foregoing. Such control logic, when executed by one or more data processing devices (such as computer system  1200 ), causes such data processing devices to operate as described herein. 
     Based on the teachings contained in this disclosure, it will be apparent to persons skilled in the relevant art(s) how to make and use aspects of the disclosure using data processing devices, computer systems and/or computer architectures other than that shown in  FIG.  12   . In particular, aspects may operate with software, hardware, and/or operating system implementations other than those described herein. 
     It is to be appreciated that the Detailed Description section, and not the Summary and 
     Abstract sections, is intended to be used to interpret the claims. The Summary and Abstract sections may set forth one or more, but not all, exemplary aspects of the disclosure as contemplated by the inventor(s), and thus, are not intended to limit the disclosure or the appended claims in any way. 
     While the disclosure has been described herein with reference to exemplary aspects for exemplary fields and applications, it should be understood that the disclosure is not limited thereto. Other aspects and modifications thereto are possible, and are within the scope and spirit of the disclosure. For example, and without limiting the generality of this paragraph, aspects are not limited to the software, hardware, firmware, and/or entities illustrated in the figures and/or described herein. Further, aspects (whether or not explicitly described herein) have significant utility to fields and applications beyond the examples described herein. 
     Aspects have been described herein with the aid of functional building blocks illustrating the implementation of specified functions and relationships thereof. The boundaries of these functional building blocks have been arbitrarily defined herein for the convenience of the description. Alternate boundaries can be defined as long as the specified functions and relationships (or equivalents thereof) are appropriately performed. In addition, alternative aspects may perform functional blocks, steps, operations, methods, etc. using orderings different from those described herein. 
     References herein to “one aspect,” “an aspect,” “some aspects,” “an example,” “some examples” or similar phrases, indicate that the aspect described may include a particular feature, structure, or characteristic, but every aspect may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same aspect. Further, when a particular feature, structure, or characteristic is described in connection with an aspect, it would be within the knowledge of persons skilled in the relevant art(s) to incorporate such feature, structure, or characteristic into other aspects whether or not explicitly mentioned or described herein. 
     The breadth and scope of the disclosure should not be limited by any of the above-described exemplary aspects, but should be defined only in accordance with the following claims and their equivalents. 
     As described above, aspects of the present technology may include the gathering and use of data available from various sources, e.g., to improve or enhance functionality. The present disclosure contemplates that in some instances, this gathered data may include personal information data that uniquely identifies or can be used to contact or locate a specific person. Such personal information data can include demographic data, location-based data, telephone numbers, email addresses, Twitter ID&#39;s, home addresses, data or records relating to a user&#39;s health or level of fitness (e.g., vital signs measurements, medication information, exercise information), date of birth, or any other identifying or personal information. The present disclosure recognizes that the use of such personal information data, in the present technology, may be used to the benefit of users. 
     The present disclosure contemplates that the entities responsible for the collection, analysis, disclosure, transfer, storage, or other use of such personal information data will comply with well-established privacy policies and/or privacy practices. In particular, such entities should implement and consistently use privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining personal information data private and secure. Such policies should be easily accessible by users, and should be updated as the collection and/or use of data changes. Personal information from users should be collected for legitimate and reasonable uses of the entity and not shared or sold outside of those legitimate uses. Further, such collection/sharing should only occur after receiving the informed consent of the users. Additionally, such entities should consider taking any needed steps for safeguarding and securing access to such personal information data and ensuring that others with access to the personal information data adhere to their privacy policies and procedures. Further, such entities can subject themselves to evaluation by third parties to certify their adherence to widely accepted privacy policies and practices. In addition, policies and practices should be adapted for the particular types of personal information data being collected and/or accessed and adapted to applicable laws and standards, including jurisdiction-specific considerations. For instance, in the US, collection of, or access to, certain health data may be governed by federal and/or state laws, such as the Health Insurance Portability and Accountability Act (HIPAA); whereas health data in other countries may be subject to other regulations and policies and should be handled accordingly. Hence different privacy practices should be maintained for different personal data types in each country. 
     Despite the foregoing, the present disclosure also contemplates embodiments in which users selectively block the use of, or access to, personal information data. That is, the present disclosure contemplates that hardware and/or software elements can be provided to prevent or block access to such personal information data. For example, the present technology may be configurable to allow users to selectively “opt in” or “opt out” of participation in the collection of personal information data, e.g., during registration for services or anytime thereafter. In addition to providing “opt in” and “opt out” options, the present disclosure contemplates providing notifications relating to the access or use of personal information. For instance, a user may be notified upon downloading an app that their personal information data will be accessed and then reminded again just before personal information data is accessed by the app. 
     Moreover, it is the intent of the present disclosure that personal information data should be managed and handled in a way to minimize risks of unintentional or unauthorized access or use. Risk can be minimized by limiting the collection of data and deleting data once it is no longer needed. In addition, and when applicable, including in certain health related applications, data de-identification can be used to protect a user&#39;s privacy. De-identification may be facilitated, when appropriate, by removing specific identifiers (e.g., date of birth, etc.), controlling the amount or specificity of data stored (e.g., collecting location data a city level rather than at an address level), controlling how data is stored (e.g., aggregating data across users), and/or other methods. 
     Therefore, although the present disclosure may broadly cover use of personal information data to implement one or more various disclosed embodiments, the present disclosure also contemplates that the various embodiments can also be implemented without the need for accessing such personal information data. That is, the various embodiments of the present technology are not rendered inoperable due to the lack of all or a portion of such personal information data.

Metadata:
Filing Date: 20210603
Publication Date: 20240312
Grant Date: 20240312
Priority Date: 20200626
Inventors: WANG, QI
LIU, YONG
JIANG, JINJING
KNECKT, JARKKO L.
VERMA, LOCHAN
WU, TIANYU
YONG, SU KHIONG
LI, GUOQING
Assignee: APPLE INC
CPC Classifications: [{"code": "H04W36/304", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W24/04", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04L45/24", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W28/082", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W52/0258", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W52/0216", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W24/04", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W52/0258", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W24/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W84/12", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y02D30/70", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W52/0258", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L45/24", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W28/082", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W84/12", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W36/304", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W36/304", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 78827144