Patent Description:
A mesh network is a network that includes electronic devices that communicate with each other wirelessly. In a mesh network, devices (sometimes called nodes) connect directly, dynamically and non-hierarchically to as many other nodes as possible and cooperate with one another to efficiently route data.

Mesh networks can be useful to gather data collected from sensor networks. In such networks, sensor devices detect conditions of nearby environments. For example, the sensor devices can be deployed in storage spaces, where the sensor devices detect occupancy statuses or a presence of an object of the storage devices. The sensor devices can also be deployed in medical facilities, where the tag devices monitor statuses of patients. In some aspects, the sensor devices transmit gathered information, such as the occupancy statuses and the patient statuses, to a source device.

In some aspects, the electronic devices of the mesh network are wireless devices. The electronic devices can be powered by internal batteries. However, the internal batteries have limited capacity and also require replacement or wired charging from time to time. The replacements and charging can be costly and troublesome.

Wireless power transmission is the transmission of electrical energy without wires as a physical link. Various techniques for wireless power charging exist. For example, power transmission may be made via radio waves, including microwaves. However, power transmission falls off quickly as the distance between a source and target device increases. For this reason, over distances, power transmission via radio waves often amounts to little more than trickle charging.

Improved methods of charging sensor devices in a mesh network are needed.

<CIT> describes, according to its abstract, an apparatus including an antenna, an energy storage device, a receiver, and an indicator assembly. The receiver may be coupled to the antenna and the energy storage device. The receiver may be configured to receive wireless energy via the antenna such that an energy storage level of the energy storage device is increased. The indicator assembly may be coupled to the receiver and may be configured, in response to the receiver receiving the wireless energy, to provide an indication based, at least in part, on a characteristic of the wireless energy.

Some aspects of this disclosure relate to apparatuses and methods for implementing power retransmissions in a mesh network. For example, systems and methods are provided for wireless power retransmissions between devices in the mesh network.

Some aspects of this disclosure relate to a device comprising a wireless transceiver configured to receive a radio frequency (RF) emission from a source device, an energy-harvesting unit configured to charge the first device wirelessly, using a first part of the RF emission, and a processor communicatively coupled to the transceiver. The processor is configured to modulate the first part of the RF emission based on information detected by the device and determine that an energy level of the device is above a threshold. The processor is further configured to transmit, in response to determining that the energy level is above the threshold, using the wireless transceiver, the modulated first part of the RF emission to the source device. The processor is further configured to transmit, in response to determining that the energy level is above the threshold, using the wireless transceiver, a second part of the RF emission wirelessly to another device to charge the other device.

Some aspects of this disclosure relate to a method of operating a device communicating with a source device. The method comprises receiving an RF emission from the source device and charging the first device wirelessly using a first part of the RF emission. The method further comprises modulating the first part of the RF emission based on information detected by the device and determining that an energy level of the device is above a threshold. The method further comprises transmitting the modulated first part of the RF emission to the source device and transmitting a second part of the RF emission wirelessly to another device to charge the other device, in response to determining that the energy level is above the threshold.

Some aspects of this disclosure relate to a system comprising a source device, a first device, and a second device. The source device is configured to transmit an RF emission wirelessly to the first device. The first device is configured to receive the RF emission from the source device and charge the first device wirelessly, using a first part of the RF emission. The first device is further configured to transmit a second part of the RF emission wirelessly to a second device. The second device is configured to receive the second part of the RF emission and charge the second device wirelessly, using the second part of the RF emission.

This Summary is provided merely for purposes of illustrating some aspects to provide an understanding of the subject matter described herein. Accordingly, the above-described features are merely examples and should not be construed to narrow the scope 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. The invention to which the present European patent relates is defined in the appended claims.

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.

The present disclosure is described with reference to the accompanying drawings. In the drawings, generally, like reference numbers indicate identical or functionally similar elements.

Disclosed herein are apparatuses and methods for implementing wireless power retransmissions in a mesh network. According to embodiments, a device receives power through RF transmission from a source device. The device assesses whether it has reached a threshold level of energy gathered through wireless charging. After it has reached the threshold level, the device transmits information it has collected to the source device. It transmits the information collected by modulating at least a portion of the RF signal it receives from the source device.

In this way, embodiments provide that the device is power by the source device wirelessly. Therefore, the device no longer requires battery or battery replacements. In addition, the threshold level ensures signal qualities of the transmission of the device when it arrives at the source device.

Electronic devices in the mesh network include, but are not limited to, tag devices, wireless sensor devices, wireless communication devices, home entertainment devices, smartphones, laptops, desktops, tablets, personal assistant devices, monitors, televisions, wearable devices, Internet of Things (IoT) devices, vehicle onboard devices, surveillance devices, and the like.

The source device can be a base station, a router, a control center, a television, customer-premises equipment, and the like. For another example, the mesh network can be a wireless sensor network that includes sensor devices, such as wireless sensors. The wireless sensors gather information, such as temperature, sound, and pressure, in locations of the wireless sensors and transmit to a source device, such as a base station. For another example, the mesh network can be a smart home network. The electronic devices can be smart home devices, such as cameras, smart meters, light control devices, home entertainment devices, and so on. A user can communicate with and control the smart home devices through a source device, such as a central computer or a smart phone.

In some aspects, the electronic devices rely on wireless charging to support operations of the electronic devices. For example, the electronic devices can harvest energies from radio frequency (RF) emissions from the source device.

In some aspects, a first electronic device locates outside a range of the source device. In other words, the RF emission from the source device does not reach the first electronic device. In such as case, a second electronic device, located between the source device and the first electronic device, can relay the RF emission from the source device to the first electronic device. For example, the second electronic device can reflects the RF emission received from the source device.

<FIG> illustrates an example system <NUM> implementing power retransmissions of a mesh network, according to some aspects of the disclosure. Example system <NUM> is provided for the purpose of illustration only and does not limit the disclosed aspects. System <NUM> may include, but is not limited to, a source device <NUM> and electronic devices <NUM>, <NUM>, and <NUM>. The source device <NUM> may include, but not limited to, a television, a base station, an access points (AP), a router, a control center, a smart phone, a computer, customer-premises equipment, and the like. The electronic devices <NUM>, <NUM>, and <NUM> may include, but is not limited to, tag devices, wireless sensor devices, wireless communication devices, smartphones, laptops, desktops, tablets, personal assistants, monitors, televisions, wearable devices, Internet of Things (IoT) devices, vehicle communication devices, and the like.

In some aspects, the electronic devices <NUM>, <NUM>, and <NUM> can communicate with each other in a mesh network. For example, the electronic device <NUM> communicates with the electronic device <NUM> via a wireless connection <NUM>. The electronic device <NUM> communicates with the electronic device <NUM> via a wireless connection <NUM>. The electronic device <NUM> can also communicate with the electronic device <NUM> indirectly via the electronic device <NUM>. In some aspects, the source device <NUM> can communicate with the electronic devices <NUM>, <NUM>, and <NUM> via wireless connections <NUM>, <NUM>, and <NUM>, respectively. In other aspects, the source device <NUM> communicates with electronic devices <NUM> and <NUM> indirectly via the electronic device <NUM>. For example, the electronic devices <NUM> and <NUM> may locate outside a range of the source device <NUM>.

In some aspects, the electronic devices <NUM>, <NUM>, and <NUM> may perform an initialization process for authentication. For example, the electronic devices <NUM>, <NUM>, and <NUM> are assigned with a pre-shared key sequence and use the pre-shared key sequence to encrypt and decrypt messages communicated among them. The electronic device <NUM> can encrypt a message with the pre-shared key and transmits the encrypted message to the electronic device <NUM> via the wireless connection <NUM>. The electronic device <NUM>, upon receiving the encrypted message, can decrypt and retrieve the message using the pre-shared key sequence. In some aspects, the electronic devices <NUM>, <NUM>, and <NUM> receive the pre-shared key sequence from a network controller (not shown). The pre-shared key sequence can also be generated by the electronic devices <NUM>, <NUM>, and <NUM>. For example, the electronic device <NUM> can generate the pre-shared key sequence and transmit it to the electronic devices <NUM> and <NUM> to be used in later communications. In other aspects, the mesh network employs asymmetric encryption. In other words, the electronic devices <NUM>, <NUM>, and <NUM> share their public key sequences with each other and encrypt the messages using the public key sequences. For example, electronic device <NUM> encrypts the message using the public key sequence of <NUM>, which is shared by the electronic device <NUM> previously, and transmits the encrypted message to the electronic device <NUM>. The electronic device <NUM>, upon receiving the encrypted message, can decrypt it using a private key of the electronic device <NUM>, wherein the private key sequence of the electronic device <NUM> corresponds to the public key sequence of the electronic device <NUM>.

In some aspects, the electronic device <NUM> can harvest energies from RF emissions received from the source device <NUM>. The RF emission includes Wi-Fi signals, Bluetooth™ signals, cellular signals, such as <NUM> signals and <NUM> signals, television signals, or other kinds of RF signals. The electronic device <NUM> can operate using the harvested energies. For example, the electronic device <NUM> can monitor patient status and/or gather environment information using the harvested energies. The electronic device <NUM> can also transmit information back to the source device <NUM> using the harvested energies.

In some aspects, the electronic device <NUM> can reflect a portion of the RF emissions received from the source device <NUM> to the electronic device <NUM>. For example, the electronic device <NUM> reflects the portion of the RF emission by changing an impedance of a transceiver of the electronic device <NUM>. In some aspects, the electronic device <NUM> reflects the portion of the RF emission by determining that an energy level of the electronic device <NUM> is above a threshold. Similarly, the electronic device <NUM> can harvest energies from the portion of the RF emission to operate. In some aspects, the electronic device <NUM> can also reflect a sub-portion of the RF emission to the electronic device <NUM> by determining that an energy level of the electronic device <NUM> is above a threshold. The thresholds of the electronic devices <NUM> and <NUM> can be the same or different.

In some aspects, the electronic device <NUM> reflects the portion of the RF emission to the electronic device <NUM> after transmitting the gathered information back to the source device <NUM>.

In some aspects, the electronic devices <NUM> and <NUM> transmit information back to the source device <NUM> indirectly. For example, the electronic device <NUM> transmits, via the wireless connection <NUM>, the information to the electronic device <NUM>, which relays the information to the source device <NUM> via the wireless connection <NUM>. Similarly, the electronic device <NUM> transmits the information to the source device <NUM> through a two-hop relay via the electronic devices <NUM> and <NUM>. In some aspects, the electronic devices <NUM> and <NUM> transmit information indirectly based on energy levels of the electronic devices <NUM> and <NUM>. In other aspects, the electronic devices <NUM> and <NUM> transmit information indirectly based on a configuration message received. For example, the source device <NUM> transmits the configuration message to the electronic devices <NUM> and <NUM> indicating indirect or direct transmissions to the source device <NUM>.

In some aspects, the source device <NUM> discovers the mesh network by broadcasting an initialization message. The initialization message may request electronic devices receiving it to send a feedback message to the source device <NUM>. The electronic devices <NUM>, <NUM>, and <NUM> may receive the initialization message and send feedback messages back to the source device <NUM> via the wireless connections <NUM>, <NUM>, and <NUM>, respectively. In some aspects, the electronic device <NUM> is physically closer to the source device <NUM> compared with the electronic devices <NUM> and <NUM>. Therefore, the feedback message from the electronic device <NUM> arrives at the source device <NUM> earlier than those of the electronic devices <NUM> and <NUM>. In such a case, the source device <NUM> determines that the electronic device <NUM> is a host device and broadcast the selection of the host device to the electronic devices <NUM>, <NUM>, and <NUM>.

In some aspects, the source device <NUM> configures the RF emission based on the selection of the host device. For example, the source device <NUM> configures one or more beams of the RF emission to point to the host device, such as the electronic device <NUM>. For another example, the source device <NUM> configures a transmission power of the RF emission based on a signal power level of the feedback message received from the host device, such as the electronic device <NUM>. Specifically, the source device <NUM> transmits the initialization message with a high power level to attempt to reach at least the electronic device <NUM> (e.g., a nearest electronic device capable of retransmission), because channel conditions of the wireless connection <NUM>, such as a path loss and fading effects, are not known. Once the source device <NUM> receives a feedback message from the electronic device <NUM>, the source device <NUM> or any involved electronic device <NUM>, <NUM>, and/or <NUM>, for example, may adjust the power level of a transmission or retransmission accordingly. For example, in some aspects, source device <NUM> may determine, based at least in part on the feedback message from electronic device <NUM> (e.g., any information contained therein or derived therefrom, with respect to power level, distance, angle, etc.), an appropriate power level for subsequent transmission to or from electronic device <NUM>. Additionally, or alternatively, electronic device <NUM> (or <NUM>, <NUM>, etc.) may determine, based at least in part on an emission from source device <NUM> (e.g., any information contained therein or derived therefrom), an appropriate power level for retransmission to any other device or back to source device <NUM>, in some aspects.

For example, a transmission power level may be increased as necessary to establish a communication link via wireless connections <NUM> or <NUM>. Additionally, or alternatively, a transmission power level may be decreased, so as to reduce possible interference that may affect other devices, for some example use cases. In order to make such adjustments, source device <NUM> or any capable electronic devices (e.g., <NUM>, <NUM>, <NUM>) may be configured, via specific circuitry, programmable circuitry, and/or any other computing means (e.g., processor <NUM>), to determine whether a power level is above or below a given threshold to establish the communication link, and/or whether a power level is above or below a given threshold sufficient to cause interference to other electronic devices within range (if such other electronic devices have been detected), according to some aspects and for some further example use cases. Based on either or both of these determinations, including via any averaging and/or weighting algorithms, source device <NUM> or electronic devices <NUM>, <NUM>, <NUM>, etc., may configure or reconfigure a power level to adjust (to raise or to lower) a power level of a transmission or retransmission, or may determine that no adjustment is needed to a power level, at least until another electronic device is detected, according to some example aspects.

In some aspects, the power level of the initialization message depends on capabilities of the source device <NUM>. For example, the source device <NUM> configures the power level of the initialization message based on a range of the source device <NUM>. The source device <NUM> can also configure the power level based on RF situations around the source device <NUM>. For example, the source device <NUM> may constrain the power level to reduce interference to other nearby devices. In addition, the source device <NUM> can configure the power level of the initialization message based on a distribution of the mesh network. For example, the source device <NUM> may determine that the mesh network of electronic devices <NUM>, <NUM>, and <NUM> has a relatively sparse distribution. In such a case, the electronic device <NUM> can configure the power level to be relatively high, such as at or near a maximum power level of the electronic device <NUM> (e.g., per device capability or configuration). On the other hand, the electronic device <NUM> may determine that the mesh network has a relatively dense distribution and may accordingly configure the power level to be lower, such as <NUM>-<NUM>% of the maximum power level of the electronic device <NUM>, in some example use cases.

In some aspects, the electronic devices <NUM>, <NUM>, and <NUM> establish the wireless connections <NUM> and <NUM> prior to receiving the initialization message from the source device <NUM>. For example, the electronic devices <NUM>, <NUM>, and <NUM> establishes the wireless connections <NUM> and <NUM> via neighbor discovery processes. Therefore, the electronic device <NUM> has location information of the electronic devices <NUM> and <NUM>. In some aspects, the electronic devices <NUM>, <NUM>, and <NUM> have location information of each other.

In some aspects, the location information includes angles of arrival. The electronic devices <NUM>, <NUM>, and <NUM> can determine the location information of each other by measuring angles of arrival. For example, the electronic device <NUM> can determine the location information of the electronic device <NUM> by measuring an angle of arrival of signals from the electronic device <NUM>, wherein the angle of arrival corresponds to a strongest receiving signal power. The electronic device <NUM> can then transmit to the electronic device <NUM> in a direction corresponding to the angle of arrival. More details of measuring the angles of arrival are discussed further below.

<FIG> illustrates a block diagram of an example system 200A of an electronic device implementing the power retransmissions of a mesh network, according to some aspects of the disclosure. The system 200A may be any of the devices (e.g., the source device <NUM> and the electronic devices <NUM>, <NUM>, and <NUM>) of the system <NUM>. The system 200A includes a processor <NUM>, one or more transceivers <NUM>, an energy-harvesting unit <NUM>, a communication infrastructure <NUM>, a memory <NUM>, an operating system <NUM>, an application <NUM>, one or more antennas <NUM>, one or more power-storage unit <NUM>, and a power-splitting unit <NUM>. Illustrated systems are provided as exemplary parts of system 200A, and system 200A may include other circuit(s) and subsystem(s). Also, although the systems of system 200A are illustrated as separate components, the aspects of this disclosure may include any combination of these, e.g., less, or more components.

The memory <NUM> may include random access memory (RAM) and/or cache, and may include control logic (e.g., computer software) and/or data. The memory <NUM> may include other storage devices or memory. According to some examples, the operating system <NUM> may be stored in the memory <NUM>. The operating system <NUM> may manage transfer of data from the memory <NUM> and/or the one or more applications <NUM> to the processor <NUM> and/or the one or more transceivers <NUM>. In some examples, the operating system <NUM> maintains one or more network protocol stacks (e.g., mesh network protocol stack, Wi-Fi protocol stack, Internet protocol stack, cellular protocol stack, and the like) that may include a number of logical layers. At corresponding layers of the protocol stack, the operating system <NUM> includes control mechanisms and data structures to perform the functions associated with that layer.

According to some examples, the application <NUM> may be stored in the memory <NUM>. The application <NUM> may include applications (e.g., user applications) used by wireless system 200A and/or a user of wireless system 200A. The applications in the application <NUM> may include applications such as, but not limited to, environment sensing, power control, configuration control, radio streaming, video streaming, remote control, and/or other user applications.

The system 200A may also include the communication infrastructure <NUM>. The communication infrastructure <NUM> provides communication between, for example, the processor <NUM>, the one or more transceivers <NUM>, the energy -harvesting unit <NUM>, the memory <NUM>, and the power-storage unit <NUM>. In some implementations, the communication infrastructure <NUM> may include a bus. In some further aspects, the communication infrastructure <NUM> or bus may additionally include a bus controller.

The processor <NUM>, alone, or together with instructions stored in the memory <NUM> performs operations enabling system 200A of the system <NUM> to implement the power retransmissions of the mesh network, as described herein. Alternatively, or additionally, the processor <NUM> can be "hard coded" to implement antenna mapping for uplink performance improvement, as described herein.

The one or more transceivers <NUM> transmit and receive communications signals support the power retransmissions of the mesh network. In some aspects, the one or more transceivers <NUM> include front end components, such as amplifiers, mixers, band-pass filters (BPFs), local oscillators, and/or other signal generators or equivalent sources, for example. The one or more transceiver <NUM> may also include a variable impendence to adjust an impedance matching. Additionally, the one or more transceivers <NUM> transmit and receive communications signals that support mechanisms for measuring communication link(s), generating and transmitting system information, and receiving the system information. According to some aspects, the one or more transceivers <NUM> may be coupled to the antenna <NUM> to wirelessly transmit and receive the communication signals. For example, the antenna <NUM> receives the RF emissions from the source device <NUM>. Antenna <NUM> may include one or more antennas that may be the same or different types. The one or more transceivers <NUM> allow system 200A to communicate with other devices that may be wired and/or wireless. In some examples, the one or more transceivers <NUM> may include processors, controllers, radios, sockets, plugs, buffers, and like circuits/devices used for connecting to and communication on networks. According to some examples, the one or more transceivers <NUM> include one or more circuits to connect to and communicate on wired and/or wireless networks.

According to some aspects of this disclosure, the one or more transceivers <NUM> may include a cellular subsystem, a sensor network 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 in the arts based on the discussion provided herein. In some implementations, the one or more transceivers <NUM> may include more or fewer systems for communicating with other devices.

In some examples, the one or more the transceivers <NUM> may 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 <NUM>.

Additionally, or alternatively, the one or more the transceivers <NUM> may 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, the transceiver <NUM> may include a Bluetooth™ transceiver.

Additionally, the one or more the transceivers <NUM> may include one or more circuits (including a cellular transceiver) for connecting to and communicating on cellular networks. The cellular networks may include, but are not limited to, <NUM>/<NUM>/<NUM> networks such as Universal Mobile Telecommunications System (UMTS), Long-Term Evolution (LTE), and the like. For example, the one or more transceivers <NUM> may be configured to operate according to one or more of Rel-<NUM>, Rel-<NUM>, Rel-<NUM>, or other releases of 3GPP standard.

The system 200A may also include the energy-harvesting unit <NUM>. The energy-harvesting unit <NUM> receives the RF emissions from the antenna <NUM>, wherein the RF emission is transmitted by the source device <NUM> or other electronic devices, such as electronic device <NUM>. Then, the RF emission received by the antenna <NUM> is split by the power-splitting unit <NUM>. The power-splitting unit <NUM> receives the RF emission from the antenna <NUM> and splits the RF emission into a first RF emission and a second RF emission. The power-splitting unit <NUM> can split the RF emission by a percentage. For example, the power-splitting unit <NUM> may split the RF emission equally. The power-splitting unit <NUM> can be a resistive power splitter, a hybrid power splitter, or other kinds of power splitters. After splitting, the power-splitting unit <NUM> transmits the first RF emission to the energy-harvesting unit <NUM> and transmits the second RF emission to the transceiver <NUM>. The energy-harvesting unit <NUM> gathers electrical energies from the first RF emission and stores the electrical energies in the power-storage unit <NUM>. The power-storage unit <NUM> is also referred to as an energy-storage unit. The power-storage unit <NUM> comprises at least one of a battery, a capacitor, or a combination thereof. In some aspects, the power-storage unit <NUM> provides the electrical energies to other components of the system 200A, such as the processor <NUM> and the transceiver <NUM>.

In some aspects, the system 200A may also include a sensor unit (not shown). The sensor unit can gather information, such as occupancy statuses, presence statutes, patient statuses, and environment information as described above. The sensor unit stores the information in the memory <NUM>. The power-storage unit <NUM> also provides the electrical energies to the sensor unit.

In some aspects, the processor <NUM>, coupled to the transceiver <NUM>, can demodulate and/or decode the second RF emission received by the transceiver <NUM>. For example, the processor <NUM> detects, from the second RF emission, a configuration message transmitted by the source device <NUM> as described above in <FIG>. In some aspects, the configuration message indicates information required by the source device <NUM>. The processor <NUM> extracts the information from the memory <NUM> and modulates the information to transmit back to the source device <NUM>. For example, the processor <NUM> modulates the information as a backscatter signal and transmits the backscatter signal to the source device <NUM> by reflecting the second RF emission. Specifically, the processor <NUM> processes a first part of the second RF emission to detect the configuration message and reflects a second part of the second RF emission back to the source device <NUM> as the backscatter signal. In other words, the second RF emission is further split into two parts.

In some aspects, the processor <NUM> modulate the second part of the second RF emission by varying power levels of the second part of the second RF emission when reflecting it back to the source device <NUM>. For example, the processor <NUM> modulates the second part of the second RF emission, such as using an ON-OFF shift keying modulation scheme and/or comparable technique(s) as described in additional detail further below. In some aspects, the ON-OFF shift keying modulation scheme may also refer to an ON-OFF keying (OOK) modulation scheme. Specifically, the transceiver <NUM> further comprises the variable impedance as described above. The processor <NUM> controls an impedance value of the variable impedance to modulate the second part of the second RF emission. The power levels of the reflected second part of the second RF emission from the antenna <NUM> to the source device <NUM> depend on matching of the impedance value of the transceiver <NUM> and an impedance value of the antenna <NUM>.

For example, as described in <FIG>, the processor <NUM> can configure the impedance value of the variable impedance to be in impedance ranges <NUM>, <NUM>, or <NUM>. The impedance range <NUM> can be a characteristic impedance range with an upper bound <NUM>, a lower bound <NUM>, and a middle point <NUM>. For example, the upper bound <NUM>, the lower bound <NUM>, and the middle point <NUM> can be <NUM> ohms, <NUM> ohms, and <NUM> ohms, respectively. When the impedance value is within the impedance range <NUM>, the second part of the second RF emission passes through and is not reflected to the source device <NUM>. Accordingly, a power level of the reflected second part of the second RF emission is low and corresponds to a power level range <NUM>. The source device <NUM> can estimate the power level based on received signals in a time period and determine that the power level is within the power level range <NUM>. In such a case, the source device <NUM> determines that a received binary value to be "<NUM>", On the other hand, the impedance value can be within the impedance ranges <NUM> and <NUM>, outside the impedance range <NUM>. In such a case, the second part of the second RF emission is reflected to the source device <NUM>. Accordingly, the power level of the reflected second part of the second RF emission is high and corresponds to power levels ranges <NUM> or <NUM>. The source device <NUM> can estimate the power level based on the received signals in a time period and determine that the power level is within the power level ranges <NUM> or <NUM>. In such a case, the source device <NUM> determines that the received binary value to be "<NUM>". In a nutshell, "<NUM>" corresponds to a high power level, and " <NUM>" corresponds to a low power level.

The reflected signals, such as the reflected second part of the second RF emission, also referred to as backscatter signals, may be modulated using ON-OFF shift keying or other modulation schemes described further below. Devices, such as the source device <NUM>, receiving the reflected second part of the second RF emission, decodes the binary sequence by measuring the power levels of the reflected second part of the second RF emission. In some aspects, the antenna <NUM> comprises a first element and a second element. In some aspects, the system 200A receives the RF emission using the first element of the antenna <NUM>, and separately reflects the second part of the second RF emission using the second element of the antenna <NUM>. In other aspects, the system 200A receives the RF emission and reflects the second part of the second RF emission both using the same element of the antenna <NUM>.

In some aspects, the processor <NUM> transmits the information by generating report signals. For example, the processor <NUM>, coupled with the transceiver <NUM>, generates a modulated signal based on the information using modulations techniques, such as amplitude modulation (AM), frequency modulation (FM), frequency shift keying (FSK), phase shift keying (PNK), binary PSK (BPSK), amplitude shift keying (ASK), ON-OFF keying (OOK or ON-OFF shift keying), quadrature amplitude modulation (QAM), and so on. In some aspects, the transceiver <NUM> further comprises a power amplifier, which amplifies the modulated signal and sends it to the antenna <NUM> for transmission. In some aspects, the power amplifier of the transceiver <NUM> can also amplify the reflected second part of the second RF emission described above.

In some aspects, the processor <NUM> controls directionalities of the antenna <NUM>. For example, the processor <NUM>, coupled with the transceiver <NUM>, controls a radiation pattern of the antenna <NUM> and points the antenna <NUM> toward a direction. The processor <NUM> can control the radiation pattern of the antenna <NUM> using components of the transceiver <NUM>, such as phase shift circuit. The processor <NUM> can control the radiation pattern of the antenna <NUM> to point to the source device <NUM> when transmitting the modulated signal or reflecting the second part of the second RF emission. In some aspects, the antenna <NUM> comprises an antenna array that includes two or more antennas. In such a case, the processor <NUM>, coupled with the transceiver <NUM>, changes the radiation pattern of the antenna <NUM> by configuring beamforming of the antenna array. In other aspects, the system 200A performs unidirectional transmission of the modulated signal or reflects the second part of the second RF emission.

In some aspects, the system <NUM>, such as the electronic device <NUM>, reflects a part of the RF emission to other devices, such as the electronic device <NUM>, in addition to the source device <NUM>. For example, the electronic device <NUM> reflects the part of the RF emission received from the source device <NUM> to the electronic <NUM> when the processor <NUM> determines that an energy level of the power-storage unit <NUM> is above a threshold. In some aspects, the processor <NUM> monitors the energy level of the power-storage unit <NUM>. The processor <NUM> may determine that the energy level is higher than the threshold while the antenna <NUM> receives the RF emission. For example, the antenna <NUM> receives RF emission in a <NUM> period. After a time point of <NUM>, the processor <NUM> may determine that the energy level is higher than the threshold. The system 200A then reflects the remaining RF emission to other electronic devices, such as the electronic device <NUM>. In some aspects, the part of the RF emission reflected by the electronic device <NUM> also includes the configuration message.

In some aspects, the system 200A reflects the remaining RF emission by controlling the variable impedance of the transceiver <NUM>. For example, the processor <NUM> changes the variable impedance of the transceiver <NUM> so that it does not match the impedance of the antenna <NUM>. In some aspects, the processor <NUM> also changes the radio pattern of the antenna <NUM> to point to the electronic device <NUM>.

In some aspects, the electronic device <NUM> determines the threshold based on the configuration message received from the source device <NUM>. For example, the configuration message includes a power level value of the threshold. In some aspects, the configuration message may indicate the threshold to be an energy level that supports certain functions of the electronic device <NUM>. For example, the threshold corresponds to energy consumptions of components of the electronic device <NUM>. The threshold may indicate <NUM> volt for operations of the processor <NUM> and indicate <NUM> volts for stable operations of the transceiver <NUM> and the memory <NUM>. For another example, the configuration message indicates the threshold to be an energy level to support the electronic device <NUM> to transmit the modulated signal or reflect the second part of the second RF emission to the source device <NUM>. In such a case, the processor <NUM> determines the threshold by estimating power consumptions of the processor <NUM> and transceiver <NUM> to transmit the modulated signal or reflect the second part of the second RF emission to the source device <NUM> or transmit to the electronic devices <NUM> and <NUM>. For example, as described in more details below, the threshold corresponds to signal qualities, such as signal-to-noise (SNR). The electronic device <NUM> can perform calibrations with the source device <NUM> and the electronic devices <NUM> and <NUM> to estimate a power level required to satisfy the signal qualities. The electronic device <NUM> can estimate by performing channel estimation or other estimations. In some aspects, the configuration message indicates the threshold to also include power consumptions of the sensor unit of the electronic device <NUM> so that the sensor unit can gather additional information. Therefore, the processor <NUM> may also estimate power consumptions of the sensor unit.

In some aspects, the configuration message indicates the threshold to be an energy level that supports functions of the electronic device <NUM> for a period of time. For example, the configuration message may indicate that the threshold supports the electronic device <NUM> to gather additional information using the sensor unit and transmit the modulated signals based on the additional information for <NUM>. The processor <NUM> then determines the threshold by estimating power consumptions in <NUM>. In some aspects, the source device <NUM> transmits the RF emission periodically. The electronic device <NUM> can determine the threshold based on the periodicity of the RF emission from the source device <NUM>. For example, the source device <NUM> transmits the RF emission for <NUM> for every <NUM>. In such a case, if the configuration message indicates a period of <NUM>, the electronic device <NUM> may determine the threshold based on a period of <NUM>, instead of the period of <NUM>, because the electronic device <NUM> can be charged by a second RF emission after <NUM>. In other words, the electronic device <NUM> considers future RF emissions when determining the threshold. In some aspects, the configuration message may indicate periodicity of RF emissions of the source device <NUM>. In other aspects, the electronic device <NUM> may infer (e.g., via averaging and/or regression) or otherwise determine the periodicity based on the RF emissions received previously.

In some aspects, the source device <NUM> determines the periodicity of the RF emission based on required information. For example, the source device <NUM> includes a request for results of monitoring a patient in the RF emission, which triggers the source devices <NUM>, <NUM>, and/or <NUM> to transmit information (e.g., regarding a patient or other subject of monitoring) back to the source device <NUM>. The source device <NUM> may transmit the RF emission every <NUM> seconds. In such a case, the information of the patient is updated every <NUM> seconds.

In other aspects, the source device <NUM> may include the request in some RF emissions. For example, the source device transmits the RF emission every <NUM> seconds. However, the source device includes the request in the RF emission every <NUM> minutes. In other words, not all RF emissions include the request. In yet another aspect, the source device <NUM> transmits the RF emission when an update of the patient information is required. To operate clocks, timers, or other means of determining or enforcing periodic actions, the source device <NUM> may include a system clock, system timer, or equivalent circuitry, systems, or services, for example, running at an equal or greater frequency (equal or shorter period or periodicity) than that of any other recurring operation or action of monitoring or generating signals or RF emissions, according to some example use cases.

In some aspects, the electronic device <NUM> can determine the threshold based on conditions of the electronic device <NUM>. For example, the electronic device <NUM> determines the threshold based on an amount of the information stored in the memory <NUM>. Specifically, the electronic device <NUM> estimates energies required to transmit the information stored in the memory <NUM>. In addition, the electronic device <NUM> can determine the threshold based on transmission of the information. For example, the electronic <NUM> waits until the transmission of the information is complete to reflect the remaining RF emission to the electronic device <NUM>. In some aspects, the electronic device <NUM> can also determine based on energies required by other devices, such as the electronic device <NUM>. For example, the electronic device <NUM> transmits a request for energy to the electronic device <NUM>. The electronic device <NUM> estimates a total energy of the RF emission and determines the threshold by deducting the requested energy from the total energy of the RF emission. In some aspects, the electronic device <NUM> considers the requested energy of the electronic device <NUM> to be the same as the electronic device <NUM>. In such a case, the electronic device <NUM> determines the threshold to be a half of the total energy of the RF emission.

In some aspects, the electronic device <NUM> also reflects the RF emission received from the electronic device <NUM> to the electronic device <NUM> in a similar way. For example, the electronic device <NUM> determines a threshold of the electronic device <NUM> as described above. The electronic device <NUM> determines that an energy level of a power-storage unit <NUM> of the electronic device <NUM> is above the threshold and reflects the remained RF emission to the electronic device <NUM>. In some aspects, the electronic device <NUM> determines location information of the electronic devices <NUM> and <NUM> in a neighboring discovery process as described above. In such as case, the processor <NUM> of the electronic device <NUM> can configure a radiation pattern of the antenna <NUM> of the electronic device <NUM> to point to the electronic device <NUM> when reflecting the RF emission to the electronic device <NUM>.

In some aspects, the electronic device <NUM> relays signals from the electronic device <NUM> to the source device <NUM>. For example, the electronic device <NUM> receives the signals from the electronic device <NUM>. The electronic device <NUM> also receives a second RF emission from the source device <NUM>. The electronic device <NUM> modulates a portion of the second RF emission based on the signals received from the source device <NUM> and transmits the modulated portion of the second RF emission back to the source device <NUM>. The electronic device <NUM> can modulate the portions of the second RF emission using the ON-OFF shift keying modulation scheme or generate a reporting message using other modulations.

As discussed in more detail below with respect to <FIG>, the system 200A may implement different mechanisms for the power retransmissions in the mesh network as discussed with respect to the system <NUM> of <FIG>.

<FIG> illustrates a block diagram of an example system 200B of an electronic device implementing the power retransmissions of a mesh network, according to some aspects of the disclosure. The system 200B may be any of the devices (e.g., the source device <NUM> and the electronic devices <NUM>, <NUM>, and <NUM>) of the system <NUM>. The system 200B includes a processor <NUM>, one or more transceivers <NUM>, an energy-harvesting unit <NUM>, a communication infrastructure <NUM>, a memory <NUM>, an operating system <NUM>, an application <NUM>, one or more antennas <NUM>, one or more power-storage unit <NUM>, a power-splitting unit <NUM>, and a matching circuit <NUM>. Illustrated systems are provided as exemplary parts of system 200B, and system 200B may include other circuit(s) and subsystem(s). Also, although the systems of system 200B are illustrated as separate components, the aspects of this disclosure may include any combination of these, e.g., less, or more components.

Functions of the processor <NUM>, the transceiver <NUM>, the energy-harvesting unit <NUM>, the communication infrastructure <NUM>, the memory <NUM>, the operating system <NUM>, the application <NUM>, the one or more antennas <NUM>, the one or more power-storage unit <NUM>, and the power-splitting unit <NUM> of the system 200B are similar to those of the system 200A of <FIG>. Either or both of the matching circuit <NUM> and/or the transceiver <NUM> may be configured to allow variable impedance. In some aspects, the matching circuit <NUM> may include a variable impedance, while the transceiver <NUM> may not include the variable impedance, for example. In other aspects, the transceiver <NUM> may include the variable impedance. The processor <NUM> controls the matching circuit <NUM> and configures an impedance value of the variable impedance. For example, the processor <NUM> can configure the impedance value to be within the characteristic impedance range <NUM>, as described above. In such a case, RF emissions received by the antenna <NUM> pass through the matching circuit <NUM> and are split to the transceiver <NUM> and the energy-harvesting unit <NUM> by the power-splitting unit <NUM>. On the other hand, the processor <NUM> can configure the impedance value to be outside the characteristic impedance range <NUM>. In such cases, the RF emissions are reflected to the source device <NUM> or the electronic devices <NUM> or <NUM>.

As discussed in more detail below with respect to <FIG>, the system 200B may implement different mechanisms for the power retransmissions in the mesh network as discussed with respect to the system <NUM> of <FIG>.

<FIG> illustrates an example method <NUM> for multi-device power retransmissions. As a convenience and not a limitation, <FIG> may be described with regard to elements of <FIG>, <FIG>, <FIG>, and <FIG>. Method <NUM> may represent the operation of devices (for example, the source device <NUM> and the electronic devices <NUM>, <NUM>, and <NUM> of <FIG>) implementing the multi-device power retransmissions. The example method <NUM> may also be performed by system 200A of <FIG> or 200B of <FIG>, controlled or implemented by processor <NUM>, and/or computer system <NUM> of <FIG>. But method <NUM> 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>.

At <NUM>, source device <NUM> transmits an RF emission to the device <NUM>. In some aspects, the RF emission includes a configuration message. The sources device <NUM> configures electronic devices, such as electronic devices <NUM>, <NUM>, and <NUM> using the configuration message. In some aspects, the source device <NUM> repeats the configuration message a plurality of times in the RF emission.

At <NUM>, the electronic device <NUM> determines a threshold. In some aspects, the configuration message includes the threshold. For example, the electronic device <NUM> decodes the RF emission and extracts the configuration message. In some aspects, because the configuration message repeats in the RF emission, the electronic device <NUM> can extract the configuration message by decoding any portions the RF emission, such as a beginning of the RF emission. In some aspects, the configuration message indicates the threshold to be an energy level to support certain functions of the electronic device <NUM> as described above. In such a case, the electronic device <NUM> determines the threshold by estimating the energy level.

At <NUM>, the electronic device <NUM> charges using a first part of the RF emission. For example, the electronic device <NUM> harvests electrical energies from the first part of the RF emission using an energy-harvesting unit <NUM> of the electronic device <NUM>. In some aspects, the electronic device <NUM> determines the first part of the RF emission based on the threshold. For example, the electronic device <NUM> estimates a current energy level of the electronic device <NUM> and determines the first part of the RF emission based on a difference between the current energy level and the threshold. The electronic device <NUM> also uses the first part of the RF emission to transmit backscatter signals. In some aspects, the electronic device <NUM> determines the first part of the RF emission by monitoring the current energy level of the electronic device <NUM>, as described below in <NUM>.

At <NUM>, the electronic device <NUM> determines that the current energy level is higher than the threshold. In some aspects, the current energy level increases as the electronic device <NUM> charges using the first part of the RF emission. The electronic device <NUM> monitors the current energy level of the electronic device <NUM> constantly and determines whether the current energy level is higher than the threshold. For example, the electronic device <NUM> monitors the current energy level by monitoring a voltage level of the power-storage unit <NUM> of the electronic device <NUM>. In some aspects, the electronic device <NUM> considers a tolerance level. For example, the electronic device <NUM> considers a tolerance level of <NUM>% and determines whether the current energy level is higher than <NUM>% of the threshold. On the other hand, the electronic device <NUM> can also determine whether the current energy level is higher than <NUM>% of the threshold. In some aspects, the electronic device <NUM> stops charging when the current power level is higher than the threshold.

In this way, by checking to determine when a threshold is reached, embodiments provide that the electronic device <NUM> has enough energies to perform certain functions, such as determining detection results in <NUM>, modulation in <NUM>, and transmission in <NUM>.

At <NUM>, the electronic device <NUM> determines detection results. In some aspects, as described above, the electronic device <NUM> can gather information, such as occupancy statuses, presence status, patient statuses, and environment information. The electronic device <NUM> can be a dedicated sensor that gathers certain kinds of information. For example, the electronic device <NUM> may be a temperature sensor that gathers temperature information of a nearby environment. In some aspects, the electronic device <NUM> can be a general sensing device. For example, the electronic device <NUM> may be able to gather patient statuses by monitoring a pulse rate, a body temperature, an oxygen level, and/or movements of a patient. In such a case, the configuration message indicates required information. For example, the configuration message may indicate the body temperature and the electronic device <NUM> measures the body temperature of a patient without gathering other information to save power.

In some aspects, the electronic device <NUM> determines detection results by receiving from a presence detector. For example, the presence detector is coupled with the electronic device <NUM> and constantly transmits the detection results to the electronic device <NUM>. In other aspects, the electronic device <NUM> can be the presence detector and transmits the detection results to the electronic device <NUM> via the wireless connection <NUM>.

At <NUM>, the electronic device <NUM> modulates the first part of the RF emission. For example, the electronic device <NUM> modulates the first part of the RF emission using the ON-OFF shift keying modulation scheme based on the detection results. The modulated first part of the RF emission can be backscatter signals. In other words, the first part of the RF emission includes a first and a second portions. The electronic device <NUM> charges using the first portion and generates the backscatter signals using the second portion. In other aspects, the electronic device <NUM> can also generate signals based on the detection results using modulation schemes such as amplitude modulation, frequency modulation, frequency shift keying, phase shift keying, amplitude shift keying, quadrature amplitude modulation, and so on.

At <NUM>, the electronic device <NUM> transmits the modulated first part of the RF emission to the source device <NUM>. In some aspects, the electronic device <NUM> controls a radiation pattern of the antenna <NUM> of electronic device <NUM> to point to the source device <NUM> when transmitting the modulated first part of the RF emission. For example, the configuration message includes location information of the source device <NUM> and the electronic device <NUM> points the antenna <NUM> towards a location of the source device <NUM> based on the location information. The electronic device <NUM> can also estimate an angle of arrival of the RF emission received from the source device <NUM> and control the radiation pattern of the antenna <NUM> based on the angle of arrival of the RF emission. For example, the electronic device <NUM> can scan <NUM>° in <NUM>° angular increments and estimate signal power levels of each incremental angle. The electronic device <NUM> can determine the angle of arrival to be an estimated angle with a strongest power level of the RF emission received from the source device <NUM>.

In some aspects, the modulated first part of the RF emission arrives at the source device <NUM> with certain signal qualities. For example, the signal qualities include a received signal power, a SNR, a bit error rate (BER), a block error rate (BLER), and so on. The source device <NUM> can configure the signal qualities using the configuration message. For example, the configuration message indicates minimum signal qualities, such as a minimum received signal power. In such a case, the electronic device <NUM> determines the threshold in <NUM> based on the minimum signal qualities. For example, the electronic device <NUM> comprises a power amplifier that amplifies the modulated first part of the RF emission so that it arrives at the source device <NUM> with a signal power that is higher than the minimum received signal power. The electronic device <NUM> can determine the threshold based on power consumptions of the power amplifier. For the same reasons above, the electronic device <NUM> transmits the modulated first part of the RF emission to the source device <NUM> when it determines that the current energy level is higher than the threshold.

In some aspects, the electronic device <NUM> also considers channel conditions of the wireless connection <NUM> when determining the threshold. For example, the transmitted modulated first part of the RF emission experiences degradation, such as a path loss, when traveling from the electronic device <NUM> to the source device <NUM>. The electronic device <NUM> amplifies the modulated first part of the RF emission to compensate for the path loss. In some aspects, the channel conditions of the wireless connection <NUM> are reciprocal. In such a case, the electronic device <NUM> estimates the channel conditions based on the RF emission received from the source device <NUM>. The source device <NUM> can also estimate the channel conditions of the wireless connection <NUM> based on signals received from the electronic device <NUM>, such as the feedback message from the electronic device <NUM>. The source device <NUM> can then include the channel conditions of the wireless connection <NUM> in the configuration message, wherein the configuration message is transmitted to the electronic device <NUM> by the source device <NUM> as described above.

At <NUM>, the electronic device <NUM> transmits a second part of the RF emission. In some aspects, the electronic device <NUM> determines the second part of the RF emission based on the first part of the RF emission. For example, the electronic device <NUM> estimates a total energy level of the RF emission and determines the second part of the RF emission by subtracting an energy level of the first part of the RF emission from the total energy level. The electronic device <NUM> can estimate the total energy level of the RF emission based on RF emissions received previously. The electronic device <NUM> can also determine the total energy level of the RF emission based on the configuration message. In some aspects, the electronic device <NUM> waits until the transmission of <NUM> completes to transmit the second part of the RF emission to the electronic device <NUM>. In other words, the electronic device <NUM> transmits to the source device <NUM> and to the electronic device <NUM> sequentially.

In some aspects, the electronic device <NUM> controls the radiation pattern of the antenna <NUM> of electronic device <NUM> to point to the electronic device <NUM> when transmitting the second part of the RF emission. For example, electronic device <NUM> determines a location of the electronic device <NUM> in a neighbor discovery process and points the antenna <NUM> towards the location of the electronic device <NUM>. The electronic device <NUM> can also predict the location of the electronic device <NUM> when the electronic device <NUM> is mobile. For example, the electronic device <NUM> determines a velocity of the electronic device <NUM> based on previous locations of the electronic device <NUM>. The electronic device <NUM> then predicts a current location of the electronic device <NUM> based on a last known location and the velocity of the electronic device <NUM>.

At <NUM>, the electronic device <NUM> charges using the second part of the RF emission similarly as the electronic device <NUM> in <NUM>.

At <NUM>, the electronic device <NUM> determines a second detection result. Similar to <NUM>, the electronic device <NUM> can gather information, such as occupancy statuses, patient statuses, and environment information. The electronic device <NUM> can be a dedicated sensor that gathers certain kinds of information. For example, the electronic device <NUM> may be a temperature sensor that gathers temperature information of a nearby environment. In some aspects, the electronic device <NUM> can be a general sensing device. For example, the electronic device <NUM> may be able to gather patient statuses by monitoring a pulse rate, a body temperature, an oxygen level, and movements of a patient. In other aspects, the configuration message indicates required information. For example, the electronic device <NUM> decodes and extracts the configuration message from the second part of the RF emission received from the electronic device <NUM>. The configuration message may indicate the body temperature and the electronic device <NUM> may measure the body temperature without gathering other information to save power.

At <NUM>, the electronic device <NUM> modulates the second part of the RF emission. The electronic device <NUM> can modulate the second part of the RF emission using at least one modulation technique, such as the ON-OFF shift keying modulation scheme, other modulation techniques disclosed elsewhere herein, or equivalent(s), based on the second detection result. The modulated second part of the RF emission can be backscatter signals. In other words, the second part of the RF emission includes a first and a second portions. The electronic device <NUM> charges using the first portion and generates the backscatter signals using the second portion. In other aspects, the electronic device <NUM> can also generate signals based on the second detection result using modulation schemes such as amplitude modulation, frequency modulation, frequency shift keying, phase shift keying, amplitude shift keying, quadrature amplitude modulation, and so on.

At <NUM>, the electronic device <NUM> transmits the modulated second part of the RF emission to the source device <NUM>. In some aspects, the electronic device <NUM> transmits to the source device <NUM> directly via the wireless connection <NUM>. The electronic device <NUM> may comprise a power amplifier that amplifies the modulated second part of the RF emission before transmission. In other aspects, the electronic device <NUM> transmits the modulated second part of the RF emission to the source device <NUM> indirectly via the electronic device <NUM>. The electronic device <NUM> may configure the modulated second part of the RF emission to indicate the indirection transmission. For example, the electronic device <NUM> can add a header in the modulated second part of the RF emission, wherein the header indicates the source device <NUM> as a destination. The electronic device <NUM>, upon receiving the modulated second part of the RF emission, can extract the destination from the header and retransmits to the source device <NUM>.

In some aspects, the electronic device <NUM> determines whether to transmit directly or indirectly based on an energy level of the electronic device <NUM>. For example, if the energy level of the electronic device <NUM> is above a direct transmission threshold, the electronic device <NUM> transmits directly to the source device <NUM>. Otherwise, the electronic device <NUM> transmits indirectly via the electronic device <NUM>. In other aspects, the electronic device <NUM> determines whether to transmit directly or indirectly based on an energy level of the second part of the RF emission. For example, when the electronic device <NUM> transmits the modulated second part of the RF emission as backscatter signals, such as the modulated second part of the RF emission, signal strengths of the backscatter signals depend on signal strengths of the second part of the RF emission received. If the signal strengths of the second part of the emission are higher than a direct backscatter threshold, the electronic device <NUM> transmits to the source device <NUM> directly via the wireless connection <NUM>. Otherwise, the electronic device <NUM> transmits indirectly via the electronic device <NUM>. In some aspects, the electronic devices <NUM>, <NUM>, and <NUM> can determine the direct backscatter threshold during an initialization period. For example, the electronic devices <NUM>, <NUM>, and <NUM> can determine the direct backscatter threshold after the initialization process for authentication as described above. The electronic device <NUM> can calibrate with the electronic device <NUM> to determine the direct backscatter threshold. The calibration can be based on signal qualities, such as an SNR, as described above.

<FIG> illustrates an example method for determining a threshold of the power retransmissions in the mesh network, as described in <NUM> of <FIG>. As a convenience and not a limitation, <FIG> may be described with regard to elements of <FIG>, <FIG>, and <FIG>. Method <NUM> may represent the operation of devices (for example, the source device <NUM> and the electronic devices <NUM>, <NUM>, and <NUM> of <FIG>) implementing the power retransmissions in the mesh network. The example method <NUM> may also be performed by system 200A of <FIG> or 200B of <FIG>, controlled or implemented by processor <NUM>, and/or computer system <NUM> of <FIG>. But method <NUM> 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>.

At <NUM>, the electronic device <NUM> determines whether a threshold expires. In some aspects, the electronic device <NUM> determines the threshold based on the configuration message received from the source device <NUM>. The configuration message may also include a lifetime of the threshold, such as <NUM> seconds. In other words, the threshold expires in <NUM> seconds after the electronic device <NUM> determines the threshold. If the threshold is expired, the control moves to <NUM>.

At <NUM>, the electronic device <NUM> decodes a first part of a RF emission received from the source device <NUM> and extracts the configuration information as described above.

At <NUM>, the electronic device <NUM> determines whether a threshold configuration is available. For example, the electronic device <NUM> determines whether the configuration message indicates the threshold. In some aspects, the configuration message includes other information, such as channel conditions and a total power level of the RF emission, but not an indication of the threshold. In other aspects, the configuration message indicates the threshold. In such a case, the control moves to <NUM>.

At <NUM>, the electronic device <NUM> resets the threshold by determining a new threshold based on the configuration message, as described in <NUM> of <FIG>.

At <NUM>, the electronic device <NUM> resets a threshold timer based on a lifetime of the threshold indicated in the configuration message.

Referring back to <NUM>, if the threshold expires, the control moves to <NUM>.

At <NUM>, the electronic device <NUM> maintains the threshold. In some aspects, the electronic device <NUM> does not extract the configuration message because there is no need to update the threshold. In other aspects, the electronic device <NUM> extracts the configuration message to obtain other information, such as channel conditions, even though the threshold is not expired.

Referring back to <NUM>, if the threshold configuration is not available in the configuration message, the control moves to <NUM>.

At <NUM>, the electronic device <NUM> estimates a total energy level of the RF emission. For example, the electronic device <NUM> determines the total energy level based on RF emissions received previously. In some aspects, the electronic device <NUM> determines the total energy level of the RF emission based on a running average of energy levels of the previously received RF emissions. For example, the electronic device <NUM> can store data representing the energy levels of the previously received RF emissions in the memory <NUM> when calculating the running average. In other aspects, the electronic device <NUM> determines the total energy level based on the configuration message.

At <NUM>, the electronic device <NUM> determines the threshold based on the total energy level. For example, the electronic device <NUM> determines the threshold to be a predetermined portion of the total energy level, such as <NUM>%. In some aspects, the electronic device <NUM> can determine the predetermined portion based on the configuration message. In some aspects, the electronic device <NUM> determines the threshold based on characteristics of the RF emission. For example, the electronic device <NUM> may determine that the RF emission includes a beacon. The electronic device <NUM> can determine based on previously received RF emissions or based on the configuration message received from the source device <NUM>. In such a case, the electronic device <NUM> splits the beacons of the RF emission equally into a first half and a second half. In other words, the threshold is <NUM>% of a total energy of the beacon.

Various aspects may be implemented, for example, using one or more computer systems, such as computer system <NUM> shown in <FIG>. Computer system <NUM> may be any computer capable of performing the functions described herein once programmed, including the functions described ins <FIG>, by source devices <NUM> and electronic devices <NUM>, <NUM>, and <NUM> of <FIG>, 200A of <FIG>, or 200B of <FIG>. Processor <NUM> is connected to a communication infrastructure <NUM> (e.g., a bus. ) Computer system <NUM> also includes user input/output device(s) <NUM>, such as monitors, keyboards, pointing devices, etc., that communicate with communication infrastructure <NUM> through user input/output interface(s) <NUM>. Computer system <NUM> also includes a main or primary memory <NUM>, such as random access memory (RAM). Main memory <NUM> may include one or more levels of cache. Main memory <NUM> has stored therein control logic (e.g., computer software) and/or data.

According to some aspects, secondary memory <NUM> 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 <NUM>. Such means, instrumentalities or other approaches may include, for example, a removable storage unit <NUM> and an interface <NUM>. Examples of the removable storage unit <NUM> and the interface <NUM> 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.

The operations in the preceding aspects may 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 <NUM>, main memory <NUM>, secondary memory <NUM> and removable storage units <NUM> and <NUM>, 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 <NUM>), 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>. In particular, aspects may operate with software, hardware, and/or operating system implementations other than those described herein.

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 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. In addition, alternative aspects may perform functional blocks, steps, operations, methods, etc. using orderings different from those described herein.

Claim 1:
A device (<NUM>, <NUM>), comprising:
one or more antennas (<NUM>) configured to receive a radio frequency, RF, emission wirelessly from a source device (<NUM>);
a power splitting circuitry (<NUM>) configured to:
split the RF emission into a first part and a second part of the RF emission based on a threshold,
transmit the first part of the RF emission to an energy harvesting circuitry (<NUM>) of the device (<NUM>,<NUM>), and
transmit the second part of the RF emission to a wireless transceiver (<NUM>) of the device (<NUM>,<NUM>);
the energy harvesting circuitry (<NUM>) configured to charge the device (<NUM>,<NUM>) using the first part of the RF emission;
the wireless transceiver (<NUM>) configured to receive the second part of the RF emission; and
a processor (<NUM>) communicatively coupled to the wireless transceiver (<NUM>) and configured to:
modulate (<NUM>) the first part of the RF emission based on information detected by the device (<NUM>,<NUM>);
determine that an energy level of an energy storage unit (<NUM>) of the device (<NUM>,<NUM>) is above the threshold (<NUM>); and
in response to determining that the energy level is above the threshold (<NUM>), transmit (<NUM>), using the wireless transceiver (<NUM>), the second part of the RF emission wirelessly to a second device (<NUM>) to charge the second device (<NUM>).