Patent Description:
Many electronic devices communicate with each other using wireless local area networks (WLANs), such as those based on a communication protocol that is compatible with an IEEE <NUM> standard (which is sometimes referred to as `Wi-Fi'). However, a radio in an electronic device that communicates using wireless communication in a WLAN may consume a significant amount of power.

In order to address this challenge, a new radio technology called Low Power Wake Up Radio (LP-WUR) is being considered. The LP-WUR may be a companion to the main Wi-Fi radio in the electronic device. Notably, by using the LP-WUR, the electronic device may turn off its main radio and may wake up the main radio in response to the LP-WUR receiving an LP-WUR packet from an access point. For example, the access point may send the LP-WUR packet when there is a down-link packet for the electronic device.

However, the connection to the access point may be lost while the main radio is in a low-power operating mode. For example, the electronic device may roam outside of the range of the access point and, thus, may need to transition to another access point. When this occurs, the electronic device may need to awaken the main radio, and then may need to perform network/service discovery. The network/service discovery typically involves the main radio scanning through multiple channels, and perform multiple frame exchanges. Each scan may take, e.g., <NUM> to capture a beacon from the other access point. Moreover, after the beacon is received, the electronic device and the other access point may need to exchange: a probe request and response, an authentication request and response, as association request and response and/or a service-information request and response. Waking up the main radio to perform the scan and to exchange these frames may increase the power and may delay the operation of the electronic device.

<CIT>, entitled "Wake on One-to-Many Communication," US Patent Application Publication <CIT>, entitled "Low Power Discontinuous Reception with a Second Receiver," US Patent Application Publication <CIT>, entitled "Waking Up Internet of Things Devices in a High Efficiency Wireless Local-Area Network," and "US Patent Application Publication <CIT>, entitled "Apparatus, System and Method of Communicating a Wakeup Packet," disclose the use of a low-power operating mode and wake-up signaling. Another prior art example is disclosed in <CIT>.

An electronic device that provides a wake-up beacon according to claim <NUM> is provided.

A recipient electronic device for receiving the wake-up beacon according to claim <NUM> is provided.

A method for providing a wake-up beacon according to claim <NUM> is also provided.

The included drawings are for illustrative purposes and serve only to provide examples of possible structures and arrangements for the disclosed systems and techniques for intelligently and efficiently managing communication between multiple associated user devices.

The embodiments will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements.

Note that like reference numerals refer to corresponding parts throughout the drawings. Moreover, multiple instances of the same part are designated by a common prefix separated from an instance number by a dash.

An interface circuit in an electronic device (such as an access point) may provide a wake-up beacon to a recipient electronic device. During operation, the interface circuit may provide a wake-up beacon (such as a LP-WUR packet) associated with a predefined sub-channel in one or more channels in a band of frequencies, where the wake-up beacon is for a wake-up radio in the recipient electronic device. Moreover, the wake-up beacon may be provided within an associated time interval, such as a keep-alive interval of the electronic device.

In some embodiments, the wake-up beacon includes a field with channel information that specifies one or more second channels used by a main radio in the recipient electronic device. Note that the one or more second channels may be different from the one or more channels. Alternatively or additionally, the wake-up beacon may include a field with service information that specifies one or more types of services and/or a field with information specifying a transmit power of the interface circuit. The transmit power may be different from another wake-up beacon provided by the interface circuit. Moreover, the wake-up beacon may include information indicating that the recipient electronic device is to awaken a main radio to receive a beacon with DFS information associated with a band of frequencies.

Furthermore, the recipient electronic device may include an interface circuit that includes a wake-up radio (such as the LP-WUR) and a main radio. During operation, the wake-up radio may receive the wake-up beacon associated with the predefined sub-channel in one or more channels in the band of frequencies, where the wake-up beacon is associated with the electronic device, and the wake-up beacon is provided within the associated time interval. Then, the wake-up radio provides, to the main radio, a wake-up signal that transitions the main radio from a low-power mode to a higher-power mode based at least in part on the wake-up beacon. When a communication metric based at least in part on a transmit power of the wake-up beacon and a received signal strength associated with the wake-up beacon degrades, the wake-up radio may perform a scan for a second wake-up beacon associated with a second electronic device (such as a second access point) in a third predefined sub-channel in one or more third channels in a third band of frequencies. Alternatively, when another wake-up beacon is not received within a subsequent time interval, the wake-up radio may perform the scan for the second wake-up beacon.

By providing the wake-up beacon, this communication technique may maintain a connection between the electronic device and the recipient electronic device. Moreover, the communication technique may facilitate more efficient operation of the main radio. For example, the main radio may not be awaken as often and may not need to perform scans as often of the wireless environment of the recipient electronic device. Consequently, the communication technique may reduce power consumption and delays, and may improve the communication performance of the electronic device and the recipient electronic device. Thus, the communication technique may improve the user experience when using the electronic device or the recipient electronic device, and therefore may increase customer satisfaction and retention.

Note that the communication technique may be used during wireless communication between electronic devices in accordance with a communication protocol, such as a communication protocol that is compatible with an IEEE <NUM> standard (which is sometimes referred to as Wi-Fi). In some embodiments, the communication technique is used with IEEE <NUM>. 11BA and/or IEEE <NUM>. 11ax, which are used as illustrative examples in the discussion that follows. However, this communication technique may also be used with a wide variety of other communication protocols, and in electronic devices (such as portable electronic devices or mobile devices) that can incorporate multiple different radio access technologies (RATs) to provide connections through different wireless networks that offer different services and/or capabilities.

An electronic device can include hardware and software to support a wireless personal area network (WPAN) according to a WPAN communication protocol, such as those standardized by the Bluetooth® Special Interest Group (in Kirkland, Washington) and/or those developed by Apple (in Cupertino, California) that are referred to as an Apple Wireless Direct Link (AWDL). Moreover, the electronic device can communicate via: a wireless wide area network (WWAN), a wireless metro area network (WMAN) a WLAN, near-field communication (NFC), a cellular-telephone or data network (such as using a third generation (<NUM>) communication protocol, a fourth generation (<NUM>) communication protocol, e.g., Long Term Evolution or LTE, LTE Advanced (LTE-A), a fifth generation (<NUM>) communication protocol, or other present or future developed advanced cellular communication protocol) and/or another communication protocol. In some embodiments, the communication protocol includes a peer-to-peer communication technique.

The electronic device, in some embodiments, can also operate as part of a wireless communication system, which can include a set of client devices, which can also be referred to as stations, client electronic devices, or client electronic devices, interconnected to an access point, e.g., as part of a WLAN, and/or to each other, e.g., as part of a WPAN and/or an `ad hoc' wireless network, such as a Wi-Fi direct connection. In some embodiments, the client device can be any electronic device that is capable of communicating via a WLAN technology, e.g., in accordance with a WLAN communication protocol. Furthermore, in some embodiments, the WLAN technology can include a Wi-Fi (or more generically a WLAN) wireless communication subsystem or radio, and the Wi-Fi radio can implement an IEEE <NUM> technology, such as one or more of: IEEE <NUM>. 11a; IEEE <NUM>. 11b; IEEE <NUM>; IEEE <NUM>-<NUM>; IEEE <NUM>. 11n; IEEE <NUM>-<NUM>; IEEE <NUM>. 11ac; IEEE <NUM>. 11ax, or other present or future developed IEEE <NUM> technologies.

In some embodiments, the electronic device can act as a communications hub that provides access to a WLAN and/or to a WWAN and, thus, to a wide variety of services that can be supported by various applications executing on the electronic device. Thus, the electronic device may include an `access point' that communicates wirelessly with other electronic devices (such as using Wi-Fi), and that provides access to another network (such as the Internet) via IEEE <NUM> (which is sometimes referred to as 'Ethernet').

Additionally, it should be understood that the electronic devices described herein may be configured as multi-mode wireless communication devices that are also capable of communicating via different <NUM> and/or second generation (<NUM>) RATs. In these scenarios, a multi-mode electronic device or UE can be configured to prefer attachment to LTE networks offering faster data rate throughput, as compared to other <NUM> legacy networks offering lower data rate throughputs. For example, in some implementations, a multi-mode electronic device is configured to fall back to a <NUM> legacy network, e.g., an Evolved High Speed Packet Access (HSPA+) network or a Code Division Multiple Access (CDMA) <NUM> Evolution-Data Only (EV-DO) network, when LTE and LTE-A networks are otherwise unavailable.

In accordance with various embodiments described herein, the terms 'wireless communication device,' 'electronic device,' 'mobile device,' 'mobile station,' 'wireless station,' 'wireless access point,' 'station,' 'access point' and 'user equipment' (UE) may be used herein to describe one or more consumer electronic devices that may be capable of performing procedures associated with various embodiments of the disclosure.

<FIG> presents a block diagram illustrating an example of electronic devices communicating wirelessly. Notably, one or more electronic devices <NUM> (such as a smartphone, a laptop computer, a notebook computer, a tablet, or another such electronic device) and access point <NUM> may communicate wirelessly in a WLAN using an IEEE <NUM> communication protocol. Thus, electronic devices <NUM> may be associated with access point <NUM>. For example, electronic devices <NUM> and access point <NUM> may wirelessly communicate while: detecting one another by scanning wireless channels, transmitting and receiving beacons or beacon frames on wireless channels, establishing connections (for example, by transmitting connect requests), and/or transmitting and receiving packets or frames (which may include the request and/or additional information, such as data, as payloads). Note that access point <NUM> may provide access to a network, such as the Internet, via an Ethernet protocol, and may be a physical access point or a virtual or 'software' access point that is implemented on a computer or an electronic device. In the discussion that follows, electronic devices <NUM> are sometimes referred to as `recipient electronic devices.

As described further below with reference to <FIG>, electronic devices <NUM> and access point <NUM> may include subsystems, such as a networking subsystem, a memory subsystem, and a processor subsystem. In addition, electronic devices <NUM> and access point <NUM> may include radios <NUM> in the networking subsystems. More generally, electronic devices <NUM> and access point <NUM> can include (or can be included within) any electronic devices with networking subsystems that enable electronic devices <NUM> and access point <NUM> to wirelessly communicate with another electronic device. This can include transmitting beacons on wireless channels to enable the electronic devices to make initial contact with or to detect each other, followed by exchanging subsequent data/management frames (such as connect requests) to establish a connection, configure security options (e.g., IPSec), transmit and receive packets or frames via the connection, etc..

As can be seen in <FIG>, wireless signals <NUM> (represented by a jagged line) are communicated by radios <NUM>-<NUM> and <NUM>-<NUM> in electronic device <NUM>-<NUM> and access point <NUM>, respectively. For example, as noted previously, electronic device <NUM>-<NUM> and access point <NUM> may exchange packets using a Wi-Fi communication protocol in a WLAN. As illustrated further below with reference to <FIG>, radio <NUM>-<NUM> may receive wireless signals <NUM> that are transmitted by radio <NUM>-<NUM>. Alternatively, radio <NUM>-<NUM> may transmit wireless signals <NUM> that are received by radio <NUM>-<NUM>. However, as described further below with reference to <FIG>, radio <NUM>-<NUM> consumes additional power in a higher-power mode. If radio <NUM>-<NUM> remains in the higher-power mode even when it is not transmitting or receiving packets, the power consumption of electronic device <NUM>-<NUM> may be needlessly increased. Consequently, electronic devices <NUM> may include wake-up radios <NUM> that listen for and/or receive wake-up beacons (and/or other wake-up communications) from access point <NUM>. When a particular electronic device (such as electronic device <NUM>-<NUM>) receives a wake-up beacon, wake-up radio <NUM>-<NUM> may selectively wake up radio <NUM>-<NUM>, e.g., provide a wake-up signal that selectively transition radio <NUM>-<NUM> from a low-power mode to the higher-power mode.

During operation, access point <NUM> (such as radio <NUM>-<NUM>) may determine whether to send a wake-up beacon to one or more recipient electronic devices (such as electronic device <NUM>-<NUM>) with information that specifies that one or more recipient electronic devices transition from the low-power mode. For example, access point <NUM> may determine whether to send a wake-up beacon to electronic device <NUM>-<NUM> based at least in part on one or more types of services for which electronic device <NUM>-<NUM> previously indicated it will awaken radio <NUM>-<NUM> (such as in a wake-up request previously provided by electronic device <NUM>-<NUM> to access point <NUM>). Then, radio <NUM>-<NUM> may provide a wake-up beacon (such as a LP-WUR packet) for the one or more recipient electronic devices (and, notably, for one or more wake-up radios <NUM>). This wake-up beacon may be associated with a predefined sub-channel in one or more channels in a band of frequencies (e.g., radio <NUM>-<NUM> may transmit the wake-up beacon in the sub-channel), and the wake-up beacon may be provided within an associated time interval, such as a keep-alive interval of access point <NUM> (such as a keep-alive interval between, e.g., <NUM> and <NUM>).

As described further below with reference to <FIG>, the wake-up beacon may include a field with channel information that specifies one or more second channels used by radio <NUM>-<NUM> in electronic device <NUM>-<NUM>. Note that the one or more second channels may be different from the one or more channels. Thus, the wake-up beacon may be used to keep or maintain a connection between electronic device <NUM>-<NUM> and access point <NUM> and to specify the one or more second channels for radio <NUM>-<NUM>. Alternatively or additionally, as described further below with reference to <FIG>, the wake-up beacon may include a field with service information that specifies one or more types of services. For example, the service information may be hashed using a predefined hash function and/or the service information may include vendor information. In these embodiments, the wake-up beacon may be used to alert electronic device <NUM>-<NUM> to downlink traffic associated with a service provided by or facilitated by access point <NUM>, such as a service for which electronic device <NUM>-<NUM> may have previously indicated it wants to be woken. Furthermore, as described further below with reference to <FIG>, the wake-up beacon may include a field with information indicating that wake-up radio <NUM>-<NUM> is to awaken radio <NUM>-<NUM> to receive a beacon with DFS information associated with the band of frequencies (which may be the same of different than the band of frequencies associated with the wake-up beacon). This information may allow radio <NUM>-<NUM> to be awoken so that it can transition to one or more different channels when the band of frequencies includes a shared spectrum, thereby cleaning the band of frequencies for a higher-priority user.

After receiving the wake-up beacon, wake-up radio <NUM>-<NUM> may provide, to radio <NUM>-<NUM>, a wake-up signal that transitions radio <NUM>-<NUM> from the low-power mode to the higher-power mode. Then, radio <NUM>-<NUM> may operate using the one or more second channels. Alternatively, when the information does not specify electronic device <NUM>-<NUM>, wake-up radio <NUM>-<NUM> may take no further action, e.g., radio <NUM>-<NUM> may remaining in the low-power mode. More generally, in some embodiments after wake-up radio <NUM>-<NUM> receives the wake-up beacon, the wake-up radio <NUM>-<NUM> may analyze the information in the wake-up beacon to determine if radio <NUM>-<NUM> should transition from the lower power mode. Thus, in the embodiments, the 'intelligence' as to whether to transition from the low-power mode in the communication technique may be implemented by access point <NUM> (such as when access point <NUM> determines whether it will send the wake-up beacon to electronic device <NUM>-<NUM>) and/or in electronic device <NUM>-<NUM> (which may analyze the information included in the wake-up beacon).

In some embodiments, electronic device <NUM>-<NUM> determines a communication metric based at least in part on a transmit power of the wake-up beacon and a received signal strength associated with the wake-up beacon. Note that the transmit power of the wake-up beacon may be specified by information included in the wake-up beacon. This may allow radio <NUM>-<NUM> to dynamically vary the transmit power in different instances of wake-up beacons provided by access point <NUM>. Alternatively or additionally, radio <NUM>-<NUM> may have previously provided a packet to electronic device <NUM>-<NUM> that included information specifying a transmit power of radio <NUM>-<NUM> (in which case the transmit power may be quasi-static). Based at least in part on the communication metric, wake-up radio <NUM>-<NUM> may perform a scan for a second wake-up beacon associated with a second electronic device (such as a second access point) in a second predefined sub-channel in one or more third channels in a third band of frequencies. For example, wake-up radio <NUM>-<NUM> may scan for another access point in a different sub-channel in the same or different channel(s) and/or band of frequencies than those used by access point <NUM>. In some embodiments, when another wake-up beacon is not received within a subsequent time interval, wake-up radio <NUM>-<NUM> performs a scan for the second wake-up beacon associated with the second electronic device in the third predefined sub-channel in the one or more third channels in the third band of frequencies.

Note that wake-up radio <NUM>-<NUM> may operate continuously or in a duty-cycle mode. For example, wake-up radio <NUM>-<NUM> may wake up to or transition to the higher-power mode from the low-power mode to receive the wake-up beacon. In some embodiments, radio <NUM>-<NUM> may provide wake-up beacons once, as needed (such as when there is downlink traffic) or periodically (such as within the associated time interval).

In these ways, the communication technique may allow electronic devices <NUM> and access point <NUM> to communicate efficiently (such as with low latency and high throughput) while significantly reducing the power consumption associated with radios <NUM> in electronic devices <NUM>. These capabilities may improve the user experience when using electronic devices <NUM>.

Note that access point <NUM> and at least some of electronic devices <NUM> may be compatible with an IEEE <NUM> standard that includes trigger-based channel access (such as IEEE <NUM>. However, access point <NUM> and at least this subset of electronic devices <NUM> may also communicate with one or more legacy electronic devices that are not compatible with the IEEE <NUM> standard (i.e., that do not use multi-user trigger-based channel access). In some embodiments, at least a subset of electronic devices <NUM> use multi-user transmission (such as orthogonal frequency division multiple access or OFDMA). For example, radio <NUM>-<NUM> may provide a trigger frame for the subset of recipient electronic devices. This trigger frame may be provided after a time delay (such as a time delay between, e.g., <NUM> and <NUM>), so that radio <NUM>-<NUM> has sufficient time to transition to the higher-power mode. Moreover, after radio <NUM>-<NUM> receives the wake-up beacon and radio <NUM>-<NUM> transitions to the higher-power mode, radio <NUM>-<NUM> may provide a group acknowledgment to radio <NUM>-<NUM>. Notably, radio <NUM>-<NUM> may provide the acknowledgment during an assigned time slot and/or in an assigned channel in the group acknowledgment. However, in some embodiments the one or more recipient electronic devices may individually provide acknowledgments to radio <NUM>-<NUM>. Thus, after radio <NUM>-<NUM> receives the wake-up beacon and radio <NUM>-<NUM> transitions to the higher-power mode, radio <NUM>-<NUM> (and, more generally, the main radios in the one or more recipient electronic devices) may provide an acknowledgment to radio <NUM>-<NUM>.

In the described embodiments, processing a packet or frame in one of electronic devices <NUM> and access point <NUM> includes: receiving wireless signals <NUM> encoding a packet or a frame; decoding/extracting the packet or frame from received wireless signals <NUM> to acquire the packet or frame; and processing the packet or frame to determine information contained in the packet or frame (such as data in the payload).

In general, the communication via the WLAN in the communication technique may be characterized by a variety of communication-performance metrics. For example, the communication-performance metric may include: a received signal strength (RSS), a data rate, a data rate for successful communication (which is sometimes referred to as a 'throughput'), a latency, an error rate (such as a retry or resend rate), a mean-square error of equalized signals relative to an equalization target, inter-symbol interference, multipath interference, a signal-to-noise ratio (SNR), a width of an eye pattern, a ratio of number of bytes successfully communicated during a time interval (such as a time interval between, e.g., <NUM> and <NUM>) to an estimated maximum number of bytes that can be communicated in the time interval (the latter of which is sometimes referred to as the 'capacity' of a communication channel or link), and/or a ratio of an actual data rate to an estimated data rate (which is sometimes referred to as 'utilization').

Although we describe the network environment shown in <FIG> as an example, in alternative embodiments, different numbers and/or types of electronic devices may be present. For example, some embodiments may include more or fewer electronic devices. As another example, in other embodiments, different electronic devices can be transmitting and/or receiving packets or frames.

<FIG> presents a flow diagram illustrating an example method <NUM> for providing a wake-up beacon. This method may be performed by an electronic device, such as an interface circuit in access point <NUM> in <FIG>. During operation, the interface circuit may determine to provide the wake-up beacon (operation <NUM>) for a wake-up radio in a recipient electronic device. For example, the interface circuit may determine to provide the wake-up beacon when there is downlink traffic (such as data associated with a service) for the recipient electronic device. Then, the interface circuit may provide the wake-up beacon (operation <NUM>) associated with a predefined sub-channel in one or more channels in a band of frequencies, where the wake-up beacon is provided within an associated time interval.

Note that the electronic device may include an access point. Moreover, the wake-up beacon may include a LP-WUR packet. Furthermore, the wake-up beacon may be compatible with an IEEE <NUM> communication protocol. Additionally, the time interval may correspond to a keep-alive interval of the electronic device and/or the recipient electronic device.

In some embodiments, the wake-up beacon includes a field with channel information that specifies one or more second channels used by a main radio in the recipient electronic device. Note that the one or more second channels may be different from the one or more channels. Alternatively or additionally, the wake-up beacon may include a field with service information that specifies one or more types of services. For example, the service information may be hashed using a predefined hash function and/or the service information may include vendor information.

Moreover, the interface circuit may be configured to provide wake-up beacons periodically.

In some embodiments, the interface circuit optionally performs one or more additional operations (operation <NUM>). For example, prior to providing the wake-up beacon (operation <NUM>), the interface circuit may: receive a wake-up request associated with the recipient electronic device (such as from the recipient electronic device) that specifies one or more types of services for which the recipient electronic device will awaken the main radio; and provide a wake-up response associated with the recipient electronic device (such as to the recipient electronic device) based at least in part on the wake-up request. Moreover, the interface circuit may provide a wake-up packet for the recipient electronic device that includes information specifying one or more services offered by the electronic device.

Furthermore, the wake-up beacon may include a field with information specifying a transmit power of the interface circuit. The transmit power may be different from another wake-up beacon provided by the interface circuit, such as a wake-up beacon that was previously provided by the interface circuit. Alternatively or additionally, prior to providing the wake-up beacon (operation <NUM>), the interface circuit may provide a packet for the electronic device that includes information specifying a transmit power of the interface circuit.

<FIG> presents a flow diagram illustrating an example method <NUM> for receiving a wake-up beacon. This method may be performed by a recipient electronic device, such as an interface circuit in electronic device <NUM>-<NUM> in <FIG>. This interface circuit may include a wake-up radio and a main radio. During operation, the wake-up radio may receive the wake-up beacon (operation <NUM>) associated with the predefined sub-channel in one or more channels in the band of frequencies, where the wake-up beacon is associated with the electronic device (such as from the electronic device), and the wake-up beacon is provided within the associated time interval. Then, the wake-up radio may optionally analyze the wake-up beacon (operation <NUM>) to determine whether to wake up the main radio. If yes (operation <NUM>), the wake-up radio may provide, to the main radio, a wake-up signal (operation <NUM>) that transitions (operation <NUM>) the main radio from a low-power mode to a higher-power mode based at least in part on the wake-up beacon. Otherwise (operation <NUM>), the wake-up radio may not take further action (operation <NUM>).

In some embodiments, the interface circuit optionally performs one or more additional operations (operation <NUM>). For example, prior to the wake-up radio receiving the wake-up beacon (operation <NUM>), the main radio may: provide the wake-up request associated with the electronic device (such as to the electronic device) that specifies the one or more types of services for which the recipient electronic device will awaken the main radio; and receive the wake-up response associated with the electronic device (such as from the electronic device) based at least in part on the wake-up request. Alternatively or additionally, the main radio may receive the wake-up packet associated with electronic device (such as from the electronic device) that includes the information specifying the one or more services offered by the electronic device.

Moreover, the recipient electronic device may determine a communication metric based at least in part on a transmit power of the wake-up beacon and an RSS associated with the wake-up beacon. Based at least in part on the communication metric, the wake-up radio may perform a scan for a second wake-up beacon associated with a second electronic device (such as another access point) in a second predefined sub-channel in one or more second channels in a second band of frequencies.

Furthermore, prior to receiving the wake-up beacon (operation <NUM>), the main radio may receive the packet associated with the electronic device (such as from the electronic device) that includes the information specifying the transmit power of the electronic device.

Additionally, when another wake-up beacon (such as a subsequent wake-up beacon) is not received within a subsequent time interval, the wake-up radio may perform a scan for the second wake-up beacon associated with the second electronic device in the second predefined sub-channel in the one or more second channels in the second band of frequencies.

In some embodiments of methods <NUM> (<FIG>) and/or <NUM>, there may be additional or fewer operations. Moreover, the order of the operations may be changed, and/or two or more operations may be combined into a single operation or performed at least partially in parallel.

In some embodiments, at least some of the operations in methods <NUM> (<FIG>) and/or <NUM> are performed by an interface circuit in the electronic device. For example, at least some of the operations may be performed by firmware executed by an interface circuit, such as firmware associated with a MAC layer, as well as one or more circuits in a physical layer in the interface circuit.

The communication technique is further illustrated in <FIG>, which presents a flow diagram illustrating an example of communication between electronic device <NUM>-<NUM> and access point <NUM>.

After associating with access point <NUM>, interface circuit <NUM> in access point <NUM> may provide a wake-up packet <NUM> for electronic device <NUM>-<NUM> that includes information specifying one or more services offered by access point <NUM>. After receiving wake-up packet <NUM>, main radio <NUM> (such as radio <NUM>-<NUM>) in interface circuit <NUM> in electronic device <NUM>-<NUM> may transmit a wake-up request <NUM> to access point <NUM> that specifies one or more types of services <NUM> for which electronic device <NUM>-<NUM> will awaken main radio <NUM>. In response, interface circuit <NUM> provides a wake-up response <NUM> (such as an acknowledgment to wake-up request <NUM> to electronic device <NUM>-<NUM>). In some embodiments, interface circuit <NUM> optionally provides a packet <NUM> (or a frame) to electronic device <NUM>-<NUM> that includes information specifying a transmit power <NUM> of interface circuit <NUM>. Main radio <NUM> may provide the information to a wake-up radio <NUM> (such as wake-up radio <NUM>-<NUM>) in interface circuit <NUM>.

Subsequently, main radio <NUM> may transition to a low-power mode <NUM>. Next, interface circuit <NUM> may determine <NUM> to provide wake-up beacon <NUM> for wake-up radio <NUM>. For example, interface circuit <NUM> may determine <NUM> to provide wake-up beacon <NUM> when there is downlink traffic (such as data associated with a service) for electronic device <NUM>-<NUM>. Moreover, interface circuit <NUM> may provide wake-up beacon <NUM> associated with a predefined sub-channel in one or more channels in a band of frequencies, where wake-up beacon <NUM> is provided within an associated time interval (such as a keep-alive interval of access point <NUM>).

In some embodiments, wake-up beacon <NUM> includes a field with information <NUM>. For example, information <NUM> may include channel information that specifies one or more second channels used by main radio <NUM>. Note that the one or more second channels may be different from the one or more channels. Alternatively or additionally, information <NUM> may include service information that specifies one or more types of services. For example, the service information may be hashed using a predefined hash function and/or the service information may include vendor information. Furthermore, information <NUM> may a transmit power of interface circuit <NUM>. The transmit power may be different from another wake-up beacon provided by interface circuit <NUM>.

After receiving wake-up beacon <NUM>, wake-up radio <NUM> may extract and analyze information <NUM>. Then, wake-up radio <NUM> may perform a remedial action. For example, wake-up radio <NUM> may provide, to main radio <NUM>, a wake-up signal <NUM> that transitions main radio <NUM> from low-power mode <NUM> to a higher-power mode <NUM> based at least in part on wake-up beacon <NUM>. Alternatively or additionally, wake-up radio <NUM> may determine a communication metric <NUM> based at least in part on a transmit power of wake-up beacon <NUM> (which may be transmit power <NUM> and/or the transmit power specified in information <NUM>) and the RSS associated with wake-up beacon <NUM>. Based at least in part on communication metric <NUM> (such as a comparison of communication metric <NUM> and the RSS or when the RSS is a predefined fraction of transmit power <NUM>), wake-up radio <NUM> may perform a scan <NUM> for a second wake-up beacon associated with a second electronic device in a second predefined sub-channel in one or more second channels in a second band of frequencies.

In some embodiments, when wake-up radio <NUM> does not receive a wake-up beacon (such as wake-up beacon <NUM> or a subsequent wake-up beacon) within a subsequent time interval, wake-up radio <NUM> may perform a scan for the second wake-up beacon associated with the second electronic device in the second predefined sub-channel in the one or more second channels in the second band of frequencies.

<FIG> presents a flow diagram illustrating an example method <NUM> for providing a wake-up beacon. This method may be performed by an electronic device, such as an interface circuit in access point <NUM> in <FIG>. During operation, the interface circuit may determine to provide the wake-up beacon (operation <NUM>) for a wake-up radio in a recipient electronic device with information indicating that the recipient electronic device is to awaken a main radio to receive a beacon with DFS information associated with a band of frequencies. Then, the interface circuit may provide the wake-up beacon (operation <NUM>) for the wake-up radio in the recipient electronic device.

<FIG> presents a flow diagram illustrating an example method <NUM> for receiving a wake-up beacon. This method may be performed by a recipient electronic device, such as an interface circuit in electronic device <NUM>-<NUM> in <FIG>. This interface circuit may include a wake-up radio and a main radio. During operation, the wake-up radio may receive the wake-up beacon (operation <NUM>) associated with the electronic device (such as from the electronic device). Then, the wake-up radio may optionally analyze the wake-up beacon (operation <NUM>) to determine whether to wake up the main radio. If yes (operation <NUM>), the wake-up radio may provide, to the main radio, a wake-up signal (operation <NUM>) that transitions (operation <NUM>) the main radio from a low-power mode to a higher-power mode based at least in part on the wake-up beacon. Moreover, the main radio may receive a beacon (operation <NUM>) associated with the electronic device (such as from the electronic device) with the DFS information associated with the band of frequencies. Otherwise (operation <NUM>), the wake-up radio may not take further action (operation <NUM>).

The communication technique is further illustrated in <FIG>, which presents a flow diagram illustrating an example of communication between electronic device <NUM>-<NUM> and access point <NUM>. Notably, after associating with access point <NUM>, main radio <NUM> in interface circuit <NUM> in electronic device <NUM>-<NUM> may transition to a low-power mode <NUM>.

Subsequently, interface circuit <NUM> may receive wireless signals <NUM> in a band of frequencies. Based at least in part on wireless signals <NUM>, interface circuit <NUM> may determine <NUM> that main radio <NUM> cannot continue to use at least a portion of the band of frequencies. Consequently, interface circuit <NUM> may determine <NUM> provide wake-up beacon <NUM> for a wake-up radio <NUM> in interface circuit <NUM> with information indicating that electronic device <NUM>-<NUM> is to awaken main radio <NUM> to receive a beacon <NUM> with DFS information <NUM> associated with the band of frequencies. Then, interface circuit <NUM> may provide wake-up beacon <NUM> for wake-up radio <NUM>.

Next, wake-up radio <NUM> may receive wake-up beacon <NUM>. In response, wake-up radio <NUM> may provide, to main radio <NUM>, a wake-up signal <NUM> that transitions main radio <NUM> from low-power mode <NUM> to a higher-power mode <NUM> based at least in part on wake-up beacon <NUM>. Subsequently, interface circuit <NUM> may provide beacon <NUM> with DFS information <NUM> for main radio <NUM>. Based at least in part on DFS information <NUM>, main radio <NUM> may discontinue using at least a portion of the band of frequencies. For example, main radio <NUM> may switch <NUM> to another channel.

In some embodiments of the LP-WUR radio technology, the communication technique is used to maintain an existing connection between an access point and a recipient electronic device, to perform scans more efficiently and/or to reduce power consumption. When a main radio of a recipient electronic device (which is sometimes referred to as a 'station') is in deep sleep mode for very long time, the recipient electronic device can roam out range of an associated access point may need to transition to another access point.

In order to discovery which access point to associate with, the recipient electronic device may need to wake up the main radio to perform network/service discovery, which usually involves scanning through multiple channels, and performing multiple frame exchanges. For example, as noted previously, each channel scan may take.g., <NUM> to receive one or more beacons. Moreover, the frames exchanged may include: a probe request/response, an authentication request/response, an association request/response; and/or a service information request/response. Waking up the main radio to conduct these frame changes can consume more power and may increase a delay in the operation of the recipient electronic device. Consequently, these challenges may degrade the communication performance, which can negatively impact user experience.

In order to address these challenges, in the communication technique a LP-WUR or wake-up beacon may be used to selectively wake-up the main radio in at least the recipient electronic device. As shown in <FIG>, which presents a drawing illustrating an example of an interface circuit <NUM> in electronic device <NUM>-<NUM>, in the communication technique a LP-WUR <NUM> (such as wake-up radio <NUM>) may be a companion radio to a main (Wi-Fi) radio <NUM>-<NUM> in interface circuit <NUM>. LP-WUR <NUM> may allow electronic device <NUM>-<NUM> to turn off main radio <NUM>-<NUM>, e.g., whenever possible. Moreover, LP-WUR <NUM> may wake up main radio <NUM>-<NUM> when wake-up beacon <NUM> (such as a LP-WUR beacon), sent from optional LP-WUR <NUM> or radio <NUM>-<NUM> in access point <NUM>, specifies electronic device <NUM>-<NUM>. Note that in some embodiments LP-WUR <NUM> is configured to receive wireless signals, while main radio <NUM>-<NUM> is configured to transmit and to receive wireless signals. In these ways, the power consumption of LP-WUR <NUM> may be very low, e.g., lower than Bluetooth Low Energy. LP-WUR <NUM> can operate in an always-on mode and/or in a duty-cycle mode. For example, in the duty-cycle mode, LP-WUR <NUM> may turn on or listen for a wake-up beacon from access point <NUM> based at least in part on a keep-alive interval of access point <NUM>.

In such a basic service set (BSS) initiated transition trigger, electronic device <NUM>-<NUM> may use wake-up beacon <NUM> (or its absence) to determine when to transition to a different BSS. For example, based at least in part on a maximum wake-up beacon interval (such as the keep-alive interval of access point <NUM>), electronic device <NUM>-<NUM> may determine when to scan for another access point. Therefore, access point <NUM> may send a wake-up beacon or a regular WUR wake-up packet to electronic device <NUM>-<NUM> within this interval. If electronic device <NUM>-<NUM> does not receive anything from access point <NUM> within the time interval, then electronic device <NUM>-<NUM> may infer that it has roamed out of range of access point <NUM> and that it needs to discover another access point (e.g., it needs to start an active scan).

Moreover, in order to facilitate fast scanning in a LP-WUR, one or more, e.g., fixed <NUM> channels (e.g., channel <NUM>) may be defined in which access point <NUM> is allowed to send a wake-up beacon. Note that the wake-up beacon may be communicated in a narrow band (or sub-channel) or multiple narrow bands in such a <NUM> channel. For example, a predefined sub-channel may include a middle, narrow tone in a <NUM> channel. In some embodiments, the wake-up beacon includes information that specifies the operating channel information for the main radio and/or service/vendor information. As described further below, the wake-up beacon may include hashed information, such as a hashed value of a service set identifier (SSID) of electronic device <NUM>-<NUM>.

The LP-WUR may also facilitate service discovery. For example, simplified service information may be included in a wake-up beacon so electronic device <NUM>-<NUM> can discovery the service it desires without waking up the main radio. Moreover, the wake-up beacon may optionally include transmit power information to help electronic device <NUM>-<NUM> estimate the distance between access point <NUM> and electronic device <NUM>-<NUM> in order to facilitate BSS transition (e.g., to assist electronic device <NUM>-<NUM> in determining when to start an active scan).

<FIG> presents a drawing illustrating an example wake-up beacon <NUM> (which may be a special type of LP-WUR packet). This wake-up beacon may have a packet format that supports service discovery on or via a LP-WUR. Notably, wake-up beacon <NUM> may include: a wake-up-radio header <NUM>, a service-information field <NUM>, optional transmit power <NUM> and/or one or more additional fields <NUM>. Service-information field <NUM> may include information such as a service identifier <NUM> subfield and/or a vendor identifier <NUM> subfield for a provider of a service. The service identifier may be defined for different services. Thus, service identifier <NUM> may specify one or more types of services. For example, a cable service may use a service identifier of '<NUM>', a television service may use service identifier '<NUM>', etc. As noted previously, at least some of the information in wake-up beacon <NUM> (such as an SSID) may be hashed using a predefined hash function (e.g., the hash function may be defined in an IEEE standard, such as IEEE <NUM>. 11BA, so that access point <NUM> and electronic device <NUM>-<NUM> use the same hash function). This is because wake-up beacon <NUM> may have a low data rate (e.g., the modulation may include on-off keying or OOK, or similar modulation that has a very low data rate, such as, e.g., <NUM> kbps). Therefore, service-information field <NUM> may not include a large number of bits. Consequently, one or more hash functions may be used to reduce the number of bits that are needed.

As noted previously, wake-up beacon <NUM> may facilitate service discovery and wake up. For example, access point <NUM> and electronic device <NUM>-<NUM> may negotiate which service identifier(s) and/or vendor identifier(s) will be used to wake up the main radio using a LP-WUR request frame and a LP-WUR response frame. When electronic device <NUM>-<NUM> sends the LP-WUR request, it may include the specific service identifier and/or the vendor identifier that it wishes to be notified using a wake-up beacon. In response, access point <NUM> may send a LP-WUR response frame. Subsequently, access point <NUM> may send a wake-up beacon to electronic device <NUM>-<NUM> when it has traffic for the particular services and/or vendors. Thus, electronic device <NUM>-<NUM> may only wake up its main radio for a particular service from a particular vendor, and more generally based at least in part on one or more wake-up criteria. Note that access point <NUM> can also send a broadcast LP-WUR packet to broadcast the one or more types of services provided by access point <NUM> to electronic devices <NUM> in its BSS. In other embodiments, the order of items in the wake-up beacon <NUM> can vary and additional and/or different items can be included.

In some embodiments, transmit-power information for access point <NUM> is used for the BSS transition. Notably, in order to facilitate the BSS transition, access point <NUM> can notify electronic device <NUM>-<NUM> of the transmission power used to send or transmit the LP-WUR packet or the wake-up beacon (such as optional transmit power <NUM> in wake-up beacon <NUM>), and electronic device <NUM>-<NUM> can use the RSS together with the transmit power to calculate the pathloss and distance between electronic device <NUM>-<NUM> and access point <NUM> (either of which may be examples of the communication metric) without waking up the main radio. Note that the transmit power used by access point <NUM> for communicating with the LP-WUR and the main radio can be different.

Alternatively or additionally, access point <NUM> can notify electronic device <NUM>-<NUM> of the transmit power for the wake-up beacons when electronic device <NUM>-<NUM> negotiates the LP-WUR mode with access point <NUM>, in which case the transmit power may have a semi-static value. However, in some embodiments the transmit power is included in the wake-up beacon, in which case the transmit power used to send the wake-up beacon or a LP-WUR packet can be dynamically changed for each wake-up beacon or LP-WUR packet. <FIG> presents a drawing illustrating an example wake-up beacon <NUM>, with a subfield that includes information specifying transmit power <NUM>.

Using the transmit power and the RSS for the wake-up beacon, electronic device <NUM>-<NUM> may determine a communication metric. Moreover, based at least in part on the determined communication metric, electronic device <NUM>-<NUM> may determine it needs to perform an active scan. For example, access point <NUM> may notify electronic device <NUM>-<NUM> of its coverage distance (such as a distance of, e.g., <NUM>) while they negotiate the LP-WUR mode (such as by exchanging the wake-up request and the wake-up reply). Then, when electronic device <NUM>-<NUM> determines that the distance to access point <NUM> is larger than the coverage distance, electronic device <NUM>-<NUM> may perform an active scan. Alternatively or additionally, electronic device <NUM>-<NUM> may determine whether to perform an active scan based at least in part on a transmit power and/or an RSS, such as based at least in part on a threshold of, e.g., -<NUM> dBm, -<NUM> dBm or -<NUM> dBm. In other embodiments, the order of items in wake-up beacon <NUM> can vary and additional and/or different items can be included.

In some embodiments, channel information is included in the wake-up beacon. For example, the channel information may indicate whether the main radio is on a different channel from the wake-up beacon. If the main radio and the LP-WUR do not use the same channel then the wake-up beacon may indicate channel number for the main radio. <FIG> presents a drawing illustrating an example wake-up beacon <NUM>, including an indication whether the main radio and the LP-WUR use the same channel <NUM> and/or a main-radio channel <NUM> (such as a channel number for the main radio).

Furthermore, in some embodiments the wake-up beacon includes a check-beacon field. Notably, because the wake-up beacon may have a very low data rate (such as a data rate associated with on-off keying modulation), it may be difficult to convey some system-update information in this radio, such as: channel switch announcement, quiet channel announcement etc. In order for electronic device <NUM>-<NUM> to get this system-update information, the wake-up beacon may include a check-beacon field to notify electronic device <NUM>-<NUM> to wake up the main radio to receive a beacon using the main radio. For example, the check-beacon field may include, e.g., a one-bit indication. This indication may indicate that access point <NUM> need to leave a DFS channel or has to quiet electronic device <NUM>-<NUM>. Thus, the wake-up beacon may indicate that the main radio needs to scan for DFS and/or needs to switch channels. In other embodiments, the order of items in wake-up beacon <NUM> can vary and additional and/or different items can be included.

In summary, a wake-up beacon may be used to allow electronic device <NUM>-<NUM> to selectively transition to the higher-power mode and/or to enable fast BSS discovery via a LP-WUR. This wake-up beacon may be communicated using, e.g., a fixed <NUM> channel. Alternatively, the wake-up beacon may be communicated using, e.g., a fixed narrowband WUR channel within the <NUM>. Moreover, the wake-up beacon or another LP-WUR packet may include service information to help electronic device <NUM>-<NUM> discover services and/or to facilitate a BSS transition. The service information may include a service identifier and/or vendor information. Furthermore, the service information may be sent using one or more hash functions to reduce the number of bits. The specific service identifier and/or the vendor identifier that are used to wake up electronic device <NUM>-<NUM> can be requested and agreed with access point <NUM>. Additionally, the wake-up beacon may include channel information for the main radio, which may allow electronic device <NUM>-<NUM> to receive the main-radio beacon faster. In some embodiments, access point <NUM> provides the transmit power to electronic device <NUM>-<NUM> in order to help electronic device <NUM>-<NUM> decide whether to transition to a different access point or to which access point to transition. The transmit-power information can be sent to the main radio or can be included in the wake-up beacon, in which case the transmit power can be dynamically changed. In some embodiments, in order to help electronic device <NUM>-<NUM> discover system-update information, the wake-up beacon includes a check-beacon field. When the check-beacon field is set, electronic device <NUM>-<NUM> may need to wake up the main radio to receive the main beacon.

While access point <NUM> woke up main radio <NUM>-<NUM> using wake-up beacon <NUM> in the preceding example, in some embodiments wake-up beacon <NUM> may be used to wake up main radios (and, more generally, to convey information to) one or more recipient electronic devices. For example, during the communication technique, access point <NUM> may define a group of one or more recipient electronic devices and may use a single wake-up beacon to wake up the main radios in the group of recipient electronic devices. However, the recipient electronic devices in the group may not all have traffic when the group wake-up beacon is received. Consequently, the wake-up beacon may include a group wake-up indication map (WIM) that is carried or conveyed in the wake-up beacon. The group-WIM may be a bitmap that is used to indicate which recipient electronic devices are being awakened (such as a subset of the group of recipient electronic devices). For example, in some embodiments, if there are ten recipient electronic devices in a group, then the group-WIM may be, e.g., a <NUM>-bit field. In other embodiments, other mapping schemes or techniques can be used.

In general, access point <NUM> may group recipient electronic devices into a wake-up group based at least in part on one or more criteria. For example, access point <NUM> may define a group based at least in part on recipient electronic devices that have similar keep-alive intervals and/or that have previously specific a common service for which they will wake up their main radios.

We now describe embodiments of an electronic device. <FIG> presents a block diagram of an electronic device <NUM> (which may be a cellular telephone, an access point, another electronic device, etc.) in accordance with some embodiments. This electronic device includes processing subsystem <NUM>, memory subsystem <NUM>, and networking subsystem <NUM>. Processing subsystem <NUM> includes one or more devices configured to perform computational operations. For example, processing subsystem <NUM> can include one or more microprocessors, application-specific integrated circuits (ASICs), graphics processing units (GPUs), microcontrollers, programmable-logic devices, and/or one or more digital signal processors (DSPs).

Memory subsystem <NUM> includes one or more devices for storing data and/or instructions for processing subsystem <NUM> and networking subsystem <NUM>. For example, memory subsystem <NUM> can include dynamic random access memory (DRAM), static random access memory (SRAM), a read-only memory (ROM), flash memory, and/or other types of memory. In some embodiments, instructions for processing subsystem <NUM> in memory subsystem <NUM> include: program instructions or sets of instructions (such as program instructions <NUM> or operating system <NUM>), which may be executed by processing subsystem <NUM>. For example, a ROM can store programs, utilities or processes to be executed in a non-volatile manner, and DRAM can provide volatile data storage, and may store instructions related to the operation of electronic device <NUM>. Note that the one or more computer programs may constitute a computer-program mechanism, a computer-readable storage medium or software. Moreover, instructions in the various modules in memory subsystem <NUM> may be implemented in: a high-level procedural language, an object-oriented programming language, and/or in an assembly or machine language. Furthermore, the programming language may be compiled or interpreted, e.g., configurable or configured (which may be used interchangeably in this discussion), to be executed by processing subsystem <NUM>. In some embodiments, the one or more computer programs are distributed over a network-coupled computer system so that the one or more computer programs are stored and executed in a distributed manner.

In addition, memory subsystem <NUM> can include mechanisms for controlling access to the memory. In some embodiments, memory subsystem <NUM> includes a memory hierarchy that comprises one or more caches coupled to a memory in electronic device <NUM>. In some of these embodiments, one or more of the caches is located in processing subsystem <NUM>.

In some embodiments, memory subsystem <NUM> is coupled to one or more high-capacity mass-storage devices (not shown). For example, memory subsystem <NUM> can be coupled to a magnetic or optical drive, a solid-state drive, or another type of mass-storage device. In these embodiments, memory subsystem <NUM> can be used by electronic device <NUM> as fast-access storage for often-used data, while the mass-storage device is used to store less frequently used data.

Networking subsystem <NUM> includes one or more devices configured to couple to and communicate on a wired and/or wireless network (i.e., to perform network operations), including: control logic <NUM>, an interface circuit <NUM> and a set of antennas <NUM> (or antenna elements) in an adaptive array that can be selectively turned on and/or off by control logic <NUM> to create a variety of optional antenna patterns or `beam patterns. ' (While <FIG> includes set of antennas <NUM>, in some embodiments electronic device <NUM> includes one or more nodes, such as nodes <NUM>, e.g., a pad, which can be coupled to set of antennas <NUM>. Thus, electronic device <NUM> may or may not include set of antennas <NUM>. ) For example, networking subsystem <NUM> can include a Bluetooth™ networking system, a cellular networking system (e.g., a <NUM>/<NUM>/<NUM> network such as UMTS, LTE, etc.), a universal serial bus (USB) networking system, a networking system based on the standards described in IEEE <NUM> (e.g., a Wi-Fi® networking system), an Ethernet networking system, and/or another networking system.

In some embodiments, networking subsystem <NUM> includes one or more radios, such as a wake-up radio that is used to receive wake-up beacons, and a main radio that is used to transmit and/or receive frames or packets during a higher-power mode. The wake-up radio and the main radio may be implemented separately (such as using discrete components or separate integrated circuits) or in a common integrated circuit.

Networking subsystem <NUM> includes processors, controllers, radios/antennas, sockets/plugs, and/or other devices used for coupling to, communicating on, and handling data and events for each supported networking system. Note that mechanisms used for coupling to, communicating on, and handling data and events on the network for each network system are sometimes collectively referred to as a 'network interface' for the network system. Moreover, in some embodiments a 'network' or a 'connection' between the electronic devices does not yet exist. Therefore, electronic device <NUM> may use the mechanisms in networking subsystem <NUM> for performing simple wireless communication between the electronic devices, e.g., transmitting advertising or beacon frames and/or scanning for advertising frames transmitted by other electronic devices.

Within electronic device <NUM>, processing subsystem <NUM>, memory subsystem <NUM>, and networking subsystem <NUM> are coupled together using bus <NUM> that facilitates data transfer between these components. Bus <NUM> may include an electrical, optical, and/or electro-optical connection that the subsystems can use to communicate commands and data among one another. Although only one bus <NUM> is shown for clarity, different embodiments can include a different number or configuration of electrical, optical, and/or electro-optical connections among the subsystems.

In some embodiments, electronic device <NUM> includes a display subsystem <NUM> for displaying information on a display, which may include a display driver and the display, such as a liquid-crystal display, a multi-touch touchscreen, etc. Display subsystem <NUM> may be controlled by processing subsystem <NUM> to display information to a user (e.g., information relating to incoming, outgoing, or an active communication session).

Electronic device <NUM> can also include a user-input subsystem <NUM> that allows a user of the electronic device <NUM> to interact with electronic device <NUM>. For example, user-input subsystem <NUM> can take a variety of forms, such as: a button, keypad, dial, touch screen, audio input interface, visual/image capture input interface, input in the form of sensor data, etc..

Electronic device <NUM> can be (or can be included in) any electronic device with at least one network interface. For example, electronic device <NUM> may include: a cellular telephone or a smartphone, a tablet computer, a laptop computer, a notebook computer, a personal or desktop computer, a netbook computer, a media player device, an electronic book device, a MiFi® device, a smartwatch, a wearable computing device, a portable computing device, a consumer-electronic device, an access point, a router, a switch, communication equipment, test equipment, as well as any other type of electronic computing device having wireless communication capability that can include communication via one or more wireless communication protocols.

Although specific components are used to describe electronic device <NUM>, in alternative embodiments, different components and/or subsystems may be present in electronic device <NUM>. For example, electronic device <NUM> may include one or more additional processing subsystems, memory subsystems, networking subsystems, and/or display subsystems. Additionally, one or more of the subsystems may not be present in electronic device <NUM>. Moreover, in some embodiments, electronic device <NUM> may include one or more additional subsystems that are not shown in <FIG>. Also, although separate subsystems are shown in <FIG>, in some embodiments some or all of a given subsystem or component can be integrated into one or more of the other subsystems or component(s) in electronic device <NUM>. For example, in some embodiments program instructions <NUM> are included in operating system <NUM> and/or control logic <NUM> is included in interface circuit <NUM>.

Moreover, the circuits and components in electronic device <NUM> may be implemented using any combination of analog and/or digital circuitry, including: bipolar, PMOS and/or NMOS gates or transistors. Furthermore, signals in these embodiments may include digital signals that have approximately discrete values and/or analog signals that have continuous values. Additionally, components and circuits may be single-ended or differential, and power supplies may be unipolar or bipolar.

An integrated circuit (which is sometimes referred to as a 'communication circuit') may implement some or all of the functionality of networking subsystem <NUM>. This integrated circuit may include hardware and/or software mechanisms that are used for transmitting wireless signals from electronic device <NUM> and receiving signals at electronic device <NUM> from other electronic devices. Aside from the mechanisms herein described, radios are generally known in the art and hence are not described in detail. In general, networking subsystem <NUM> and/or the integrated circuit can include any number of radios. Note that the radios in multiple-radio embodiments function in a similar way to the described single-radio embodiments.

In some embodiments, networking subsystem <NUM> and/or the integrated circuit include a configuration mechanism (such as one or more hardware and/or software mechanisms) that configures the radio(s) to transmit and/or receive on a given communication channel (e.g., a given carrier frequency). For example, in some embodiments, the configuration mechanism can be used to switch the radio from monitoring and/or transmitting on a given communication channel to monitoring and/or transmitting on a different communication channel. (Note that 'monitoring' as used herein comprises receiving signals from other electronic devices and possibly performing one or more processing operations on the received signals).

In some embodiments, an output of a process for designing the integrated circuit, or a portion of the integrated circuit, which includes one or more of the circuits described herein may be a computer-readable medium such as, for example, a magnetic tape or an optical or magnetic disk. The computer-readable medium may be encoded with data structures or other information describing circuitry that may be physically instantiated as the integrated circuit or the portion of the integrated circuit. Although various formats may be used for such encoding, these data structures are commonly written in: Caltech Intermediate Format (CIF), Calma GDS II Stream Format (GDSII) or Electronic Design Interchange Format (EDIF). Those of skill in the art of integrated circuit design can develop such data structures from schematic diagrams of the type detailed above and the corresponding descriptions and encode the data structures on the computer-readable medium. Those of skill in the art of integrated circuit fabrication can use such encoded data to fabricate integrated circuits that include one or more of the circuits described herein.

While the preceding discussion used a Wi-Fi communication protocol as an illustrative example, in other embodiments a wide variety of communication protocols and, more generally, wireless communication techniques may be used. Thus, the communication technique may be used in a variety of network interfaces. Furthermore, while some of the operations in the preceding embodiments were implemented in hardware or software, in general the operations in the preceding embodiments can be implemented in a wide variety of configurations and architectures. Therefore, some or all of the operations in the preceding embodiments may be performed in hardware, in software or both. For example, at least some of the operations in the communication technique may be implemented using program instructions <NUM>, operating system <NUM> (such as a driver for interface circuit <NUM>) or in firmware in interface circuit <NUM>. Alternatively or additionally, at least some of the operations in the communication technique may be implemented in a physical layer, such as hardware in interface circuit <NUM>. In some embodiments, the communication technique is implemented, at least in part, in a MAC layer and/or in a physical layer in interface circuit <NUM>.

While examples of numerical values are provided in the preceding discussion, in other embodiments different numerical values are used. Consequently, the numerical values provided are not intended to be limiting.

While the preceding embodiments illustrated the use of a wake-up beacon that is communicated using Wi-Fi, in other embodiments of the communication technique Bluetooth Low Energy is used to communicate the wake-up beacon. Furthermore, the wake-up beacon may be communicated in the same or a different band of frequencies that the band(s) of frequencies used by the main radio. For example, the wake-up beacon may be communicated in one or more bands of frequencies, including: <NUM>, <NUM>, <NUM>, <NUM>, and/or a band of frequencies used by LTE.

In the preceding description, we refer to 'some embodiments. ' Note that `some embodiments' describes a subset of all of the possible embodiments, but does not always specify the same subset of embodiments.

Claim 1:
An electronic device (<NUM>), comprising:
a node (<NUM>) configured to communicatively couple to an antenna (<NUM>); and
an interface circuit (<NUM>), communicatively coupled to the node (<NUM>), configured to communicate with a recipient electronic device (<NUM>-<NUM>), and configured to:
group the recipient electronic device (<NUM>-<NUM>) into a wake-up group of recipient electronic devices having keep-alive intervals within a predefined range or that have a common service for which they will wake up their main radios, wherein the recipient electronic device has a main radio and a wake-up radio;
provide, to the node (<NUM>), a wake-up beacon (<NUM>) associated with a predefined sub-channel in one or more channels in a band of frequencies, wherein the wake-up beacon (<NUM>) is for a wake-up radio (<NUM>-<NUM>) in the recipient electronic device (<NUM>-<NUM>);
wherein the wake-up beacon (<NUM>) is provided within an associated time interval; and
wherein the associated time interval corresponds to a keep-alive interval of the electronic device (<NUM>) such that the absence of a wake-up beacon during the keep-alive interval causes the recipient electronic device (<NUM>-<NUM>) to scan for another electronic device.