U.S. patent application number 16/275217 was filed with the patent office on 2019-06-13 for method and apparatus for wireless transmission and reception of power.
The applicant listed for this patent is Atmosic Technologies Inc.. Invention is credited to Jason Chih-way Hou, Teresa Huai-Ying Meng, David Su, Manolis Terrovitis, Masoud Zargari.
Application Number | 20190181687 16/275217 |
Document ID | / |
Family ID | 66696469 |
Filed Date | 2019-06-13 |
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United States Patent
Application |
20190181687 |
Kind Code |
A1 |
Su; David ; et al. |
June 13, 2019 |
METHOD AND APPARATUS FOR WIRELESS TRANSMISSION AND RECEPTION OF
POWER
Abstract
Method and apparatus for wirelessly transmitting and receiving
power between devices are provided. A first device may convert
power into RF energy and transmit the RF energy to a second device.
In some implementations, the first device may steer the RF energy
using beamforming techniques to the second device. The second
device may receive and convert the RF energy into power for the
second device. In some implementations, the second device may be
powered solely or in part by power transmitted by the first device.
In some implementations, the first device may include two or more
RF energy harvesters and a power combiner. The power combiner may
combine power from the two or more RF energy harvesters to power
the second device and/or charge a battery.
Inventors: |
Su; David; (Saratoga,
CA) ; Terrovitis; Manolis; (Athens, GR) ;
Zargari; Masoud; (Irvine, CA) ; Hou; Jason
Chih-way; (San Jose, CA) ; Meng; Teresa
Huai-Ying; (San Francisco, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Atmosic Technologies Inc. |
Campbell |
CA |
US |
|
|
Family ID: |
66696469 |
Appl. No.: |
16/275217 |
Filed: |
February 13, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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15836504 |
Dec 8, 2017 |
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16275217 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H02J 50/001 20200101;
H04B 5/0062 20130101; H02J 50/20 20160201; H02J 50/40 20160201;
H04B 5/0037 20130101; H04B 5/0031 20130101 |
International
Class: |
H02J 50/20 20060101
H02J050/20; H04B 5/00 20060101 H04B005/00 |
Claims
1. A first wireless device for transmitting power to a second
wireless device, the first wireless device comprising: a first
antenna; and a first transceiver coupled to the first antenna and
configured to: transmit one or more radio frequency (RF)
pre-charging pulses to the second wireless device, the one or more
RF pre-charging pulses including energy available for power
harvesting by the second wireless device; and transmit a target
identification (ID) value to identify the second wireless
device.
2. The first wireless device of claim 1, wherein the target ID
value is encoded in the one or more RF pre-charging pulses.
3. The first wireless device of claim 1, wherein the one or more RF
pre-charging pulses are transmitted during a first time period, and
the target ID value is transmitted during a second time period
subsequent to the first time period.
4. The first wireless device of claim 1, wherein a transmit duty
cycle of the one or more RF pre-charging pulses and the target ID
is configured to limit an effective isotropic radiated power (EIRP)
of the transmitted RF pre-charging pulses and the target ID
value.
5. The first wireless device of claim 1, wherein a peak-to-average
power ratio of the one or more RF pre-charging pulses and the
target ID is configured to limit an effective isotropic radiated
power (EIRP) of the transmitted RF pre-charging pulses and the
target ID value.
6. The first wireless device of claim 1, wherein the target ID
value is selected from the group consisting of a device ID assigned
to a particular wireless device, a group ID assigned to a plurality
of wireless devices, and a broadcast ID addressing all wireless
devices within wireless range of the first wireless device.
7. The first wireless device of claim 1, further comprising: a
second antenna; and a second transceiver coupled to the second
antenna, the first transceiver and the second transceiver
configured to beamform the one or more RF pre-charging pulses in a
direction of the second wireless device.
8. The first wireless device of claim 7, wherein: the first
transceiver is configured to receive feedback data from the second
wireless device; and the first and second transceivers are
configured to beamform the one or more RF pre-charging pulses based
on the feedback data.
9. The first wireless device of claim 1, wherein the one or more RF
pre-charging pulses are modulated in accordance with one of a Wi-Fi
protocol, a Bluetooth protocol, or a Bluetooth Low Energy
protocol.
10. The first wireless device of claim 1, wherein the one or more
RF pre-charging pulses are transmitted in one of a 6 MHz, a 13 MHz,
a 27 MHz, a 40 MHz, a 400 MHz, a 900 MHz, a 2.4 GHz, and a 5 GHz
frequency band.
11. The first wireless device of claim 1, wherein the RF
pre-charging pulses are transmitted in a first frequency band, and
the target ID value is transmitted in a second frequency band
distinct from the first frequency band.
12. The first wireless device of claim 1, wherein the RF
pre-charging pulses are transmitted in response to receiving a
request a transmission of RF energy from the second wireless
device.
13. A method for transmitting power by a first wireless device,
comprising: transmitting, by a first transceiver of the first
wireless device, one or more radio frequency (RF) pre-charging
pulses to a second wireless device, the one or more RF pre-charging
pulses including energy available for power harvesting; and
transmitting a target identification (ID) value to identify the
second wireless device.
14. The method of claim 13, wherein the target ID value is encoded
in the one or more RF pre-charging pulses.
15. The method of claim 13, wherein the one or more RF pre-charging
pulses are transmitted during a first time period, and the target
ID value is transmitted during a second time period subsequent to
the first time period.
16. The method of claim 13, wherein a transmit duty cycle of the
one or more RF pre-charging pulses and the target ID are configured
to limit an effective isotropic radiated power (EIRP) of the
transmitted RF pre-charging pulses and the target ID value.
17. The method of claim 13, wherein a peak-to-average power ratio
of the one or more RF pre-charging pulses and the target ID are
configured to limit an effective isotropic radiated power (EIRP) of
the transmitted RF pre-charging pulses and the target ID value.
18. The method of claim 13, wherein the target ID value is selected
from the group consisting of a device ID assigned to a particular
wireless device, a group ID assigned to a plurality of wireless
devices, and a broadcast ID addressing all wireless devices within
wireless range of the first wireless device.
19. The method of claim 13, further comprising: transmitting, by a
second transceiver of the first wireless device, one or more
beamformed RF pre-charging pulses to the second wireless
device.
20. The method of claim 19, wherein: the first transceiver is
configured to receive feedback data from the second wireless
device; and the first and second transceivers are configured to
beamform the one or more RF charging pulses based on the feedback
data.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional application, and claims the
benefit of co-pending and commonly owned U.S. patent application
Ser. No. 15/836,504 entitled "METHOD AND APPARATUS FOR WIRELESS
TRANSMISSION AND RECEPTION OF POWER," filed on Dec. 8, 2017, which
is hereby incorporated by reference in its entirety.
TECHNICAL FIELD
[0002] The present embodiments relate generally to wireless
devices, and specifically to methods and apparatus for wireless
transmission and reception of power between wireless devices.
BACKGROUND OF RELATED ART
[0003] Portable devices (such as wireless communication devices,
wireless sensors, and IoT devices) are often battery powered to
provide mobility and convenience. Reducing the power consumption of
wireless communication devices may extend battery life and thereby
increase the time between battery recharging or replacement. Due to
size constraints, portable devices typically include batteries
having very limited power capacities or, in some instances, may not
include any battery.
[0004] Thus, there is a need to wirelessly transfer power to
devices with limited on-board power resources.
SUMMARY
[0005] This Summary is provided to introduce in a simplified form a
selection of concepts that are further described below in the
Detailed Description. This Summary is not intended to identify key
features or essential features of the claimed subject matter, nor
is it intended to limit the scope of the claimed subject
matter.
[0006] An apparatus and method are disclosed that may allow power
to be wirelessly transmitted between wireless communication
devices. In a first example, a wireless device for transmitting
power to a second wireless device is disclosed and may include an
antenna, a transceiver coupled to the antenna configured to
transmit one or more radio frequency pre-charging pulses for power
harvesting at the second wireless device, and transmit a target
identification value to identify the second wireless device.
[0007] In another example, another wireless device is disclosed and
may include an antenna, a transceiver coupled to the first antenna
and configured to decode a target identification (ID) value
included in a received RF signal, the transceiver comprising a
plurality of energy harvesting units configured to convert the
received RF signal into power for at least a portion of the device,
and a controller configured to assert a signal in response to
matching the target ID with a device ID that identifies the
device.
[0008] In another example, a method for operating a wireless device
is disclosed and may include determining a location of a second
wireless device, determining beamforming parameters based on the
determined location, and transmitting a beamformed paging signal to
provide power to the second wireless device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Aspects of the present disclosure are illustrated by way of
example and are not intended to be limited by the figures of the
accompanying drawings. Like numbers reference like elements
throughout the drawings and specification.
[0010] FIG. 1 depicts a wireless communication system within which
example embodiments may be implemented.
[0011] FIG. 2 is a block diagram of an example host device.
[0012] FIG. 3 is a block diagram of an example client device.
[0013] FIGS. 4A-4C are diagrams of example implementations of
paging signals.
[0014] FIG. 5 is a flowchart depicting an example operation for
operating a host device, in accordance with some embodiments.
[0015] FIG. 6 is a flowchart depicting an example operation for
operating a client device, in accordance with some embodiments.
DETAILED DESCRIPTION
[0016] In the following description, numerous specific details are
set forth such as examples of specific components, circuits, and
processes to provide a thorough understanding of the disclosure.
The term "coupled" as used herein means coupled directly to or
coupled through one or more intervening components or circuits.
Also, in the following description and for purposes of explanation,
specific nomenclature is set forth to provide a thorough
understanding of the example embodiments. However, it will be
apparent to one skilled in the art that these specific details may
not be required to practice the example embodiments. In other
instances, well-known circuits and devices are shown in block
diagram form to avoid obscuring the disclosure. Any of the signals
provided over various buses described herein may be
time-multiplexed with other signals and provided over one or more
common buses. Additionally, the interconnection between circuit
elements or software blocks may be shown as buses or as single
signal lines. Each of the buses may alternatively be a single
signal line, and each of the single signal lines may alternatively
be buses, and a single line or bus might represent any one or more
of a myriad of physical or logical mechanisms for communication
between components. The example embodiments are not to be construed
as limited to specific examples described herein but rather to
include within their scope all embodiments defined by the appended
claims.
[0017] The techniques described herein may be implemented in
hardware, software, firmware, or any combination thereof, unless
specifically described as being implemented in a specific manner.
Any features described as modules or components may also be
implemented together in an integrated logic device or separately as
discrete but interoperable logic devices. If implemented in
software, the techniques may be realized at least in part by a
non-transitory computer-readable storage medium comprising
instructions that, when executed, performs one or more of the
methods described below. The non-transitory computer-readable
storage medium may form part of a computer program product, which
may include packaging materials.
[0018] The non-transitory computer-readable storage medium may
include random access memory (RAM) such as synchronous dynamic
random access memory (SDRAM), read only memory (ROM), non-volatile
random access memory (NVRAM), electrically erasable programmable
read-only memory (EEPROM), FLASH memory, other known storage media,
and the like. The techniques additionally, or alternatively, may be
realized at least in part by a computer-readable communication
medium that carries or communicates code in the form of
instructions or data structures and that may be accessed, read,
and/or executed by a computer or other processor.
[0019] The various illustrative logical blocks, modules, circuits
and instructions described in connection with the implementations
disclosed herein may be executed by one or more processors, such as
one or more digital signal processors (DSPs), general purpose
microprocessors, application specific integrated circuits (ASICs),
application specific instruction set processors (ASIPs), field
programmable gate arrays (FPGAs), or other equivalent integrated or
discrete logic circuitry. The term "processor," as used herein may
refer to any of the foregoing structure or any other structure
suitable for implementation of the techniques described herein. In
addition, in some aspects, the functionality described herein may
be provided within dedicated software modules or hardware modules
configured as described herein. Also, the techniques could be fully
implemented in one or more circuits or logic elements. A
general-purpose processor may be a microprocessor, but in the
alternative, the processor may be any conventional processor,
controller, microcontroller, or state machine. A processor may also
be implemented as a combination of computing devices (such as a
combination of a DSP and a microprocessor), a plurality of
microprocessors, one or more microprocessors in conjunction with a
DSP core, or any other suitable configuration.
[0020] FIG. 1 depicts a wireless communication system 100 within
which aspects of the present disclosure may be implemented. The
wireless communication system 100 may include one or more wireless
communication devices such as a host device 110 and client devices
120 and 130. The host device 110 and the client devices 120 and 130
may be any suitable wireless communication device. Example wireless
communication devices may include a cell phone, personal digital
assistant (PDA), tablet device, laptop computer, or any other
suitable portable device. The host device 110 and the client
devices 120 and 130 may also be referred to as a user equipment
(UE), a subscriber station, a mobile unit, a subscriber unit, a
wireless unit, a remote unit, a mobile device, a wireless device, a
wireless communications device, a remote device, a mobile
subscriber station, an access terminal, a mobile terminal, a
wireless terminal, a remote terminal, a handset, a user agent, a
mobile client, a client, or some other suitable terminology.
[0021] For ease of explanation and clarity, the wireless
communication system 100 depicts a single host device 110 and two
client devices 120 and 130. In other embodiments, the wireless
communication system 100 may include any technically feasible
number of host devices and/or client devices. The host device 110
and the client devices 120 and 130 may communicate with each other
via one or more technically feasible wireless communication
protocols. In some implementations, the host device 110 and the
client devices 120 and 130 may communicate with each other (and
with other devices not shown for simplicity) via Wi-Fi,
Bluetooth.RTM., Bluetooth Low Energy (BLE), Long Term Evolution
(LTE), or any other suitable communication protocol. In some other
implementations, the host device 110 and client devices 120 and 130
may operate within the 900 MHz band, the 2.4 GHz industrial,
scientific, and medical (ISM) band, the 5 GHz ISM band, the 60 GHz
band or any other technically feasible frequency band.
[0022] In some implementations, the client devices 120 and 130 may
be battery powered (or may receive power from external power
sources), and may be capable of operating in a number of different
power modes or states. In some aspects, client devices 120 and 130
may operate in either a low-power state or an active power state.
In the low-power state, operations of one or more portions of the
client devices 120 and 130 may be suspended and/or one or more
circuits and components of the client devices 120 and 130 may be
powered down to reduce power consumption. In the active power
state, portions of the client devices 120 and 130 that were powered
down during the low-power state may be powered on, for example, so
that the client devices 120 and 130 are fully operational (such as
being capable of transmitting signals, receiving signals, and
processing signals).
[0023] In some other implementations, the client devices 120 and
130 may not be battery or alternating current (AC) powered, but may
instead derive power from transmitted RF energy. For example, the
client devices 120 and 130 may be small, remote devices for which
battery and/or external power sources are not feasible, available,
or desirable. In some aspects, the client devices 120 and 130 may
be environmental sensors (such as temperature sensors, air pressure
sensors, humidity sensors, and the like), door position sensors,
window position sensors, and the like. In other aspects, the client
devices 120 and 130 may be any suitable IoT device (such as
sensors, motion detectors, relay devices, and so on).
[0024] In some implementations, the client device 120 may include a
power receiver/communication circuit 125. The power
receiver/communication circuit 125 may receive RF energy from the
host device 110 (or any other nearby device that transmits or emits
RF energy), and convert the RF energy into power (such as
voltage/current) for the client device 120. In this manner, some of
the operations of the client device 120 may be powered by RF energy
transmitted from the host device 110. In addition, the power
receiver/communication circuit 125 may provide communication
functionality for the client device 120. For example, the power
receiver/communication circuit 125 may include a transceiver to
wirelessly transmit and receive data between the client device 120
and the host device 110, between the client device 120 and the
client device 130, and/or between the client device 120 and one or
more other wireless devices (not shown for simplicity). Similar to
the client device 120, the client device 130 may also include a
power receiver/communication circuit 135 to convert RF energy into
power and provide communication functionality.
[0025] In some implementations, the host device 110 may be powered
by a battery or through an external power source, for example, and
well suited to transmit power via RF energy to the client devices
120 and/or 130. In some implementations, the host device 110 may
include a power transmitter/communication circuit 115. The power
transmitter/communication circuit 115 may convert power from a
local power source (such as battery power and/or an external power
source, not shown for simplicity) into RF energy that may be
transmitted to other wireless devices (such as the client devices
120 and 130). In addition, the power transmitter/communication
circuit 115 may provide communication functionality for the host
device 110. For example, the power transmitter/communication
circuit 115 may include a transceiver to wirelessly transmit and
receive data between the host device 110 and a number of other
devices (such as the client devices 120 and 130).
[0026] In some implementations, the power transmitter/communication
circuit 115 may transmit a paging signal to the client devices 120
and 130. The paging signal may include one or more RF pre-charging
pulses. The RF pre-charging pulses may be pulses of RF energy that
may be used to power, at least partially, the client devices 120
and 130. In addition, the paging signal may include a target
identification (ID) field or value that identifies or addresses a
specific device, such as the client device 120 or the client device
130. In some implementations, the target ID may be a MAC address,
an IP address, or any other number or value that may be associated
with and/or used to identify or address the client device 120
and/or the client device 130.
[0027] In some implementations, the target ID may be a group ID
associated with a group of client devices (such as devices that
share a common device class, a common family, and/or a common
location), for example, so that the paging signal may identify or
address a group of client devices. In some aspects, the target ID
may correspond to client devices that are located in a common area.
In other aspects, the target ID may correspond to client devices
that perform a similar function. In some other implementations, the
target ID may be a broadcast ID that allows the paging signal to
identify or address all client devices within wireless range of the
host device 110.
[0028] Portions of the paging signal (such as the RF pre-charging
pulses and/or the target ID) may power at least a portion of a
client device. In some implementations, the paging signal may be
used to wake-up one or more other devices (such as the client
devices 120 and 130). The client devices 120 and 130 each may
determine whether the paging signal is addressed to or identifies
the respective client device. If the paging signal addresses or
identifies a given client device, then the given client device may
transition from the low power state to the active power state, for
example, based on reception of the paging signal identifying the
client device. Conversely, if the paging signal does not address or
identify the given client device, then the given client device may
remain in its current power state (such as not transitioning from
the low power state to the active power state).
[0029] As described above, the host device 110 may provide power to
the client devices 120 and 130 by transmitting RF energy. In some
instances, the client device 120 or 130 may include a power storage
device that is running low on charge. In response, the client
device 120 or 130 may request that the host device 110 increase the
amount of transmitted RF energy, even in conditions when the host
device 110 has no data to transmit.
[0030] In some aspects, the paging signal may be transmitted within
frequency bands that may be shared with other transceivers provided
within the client devices 120 and 130, respectively. For one
example, the client devices 120 and 130 may include one or more
transceivers (including Wi-Fi and Bluetooth transceivers) that
operate within a 6 MHz, a 13 MHz, a 27 MHz, a 40 MHz, a 400 MHz, a
900 MHz, a 2.4 GHz, a 5 GHz, and a 60 GHz industrial, scientific,
and medical (ISM) band. In another example, the client devices 120
and 130 may include one or more cellular transceivers that operate
within various frequency bands (some of which may overlap frequency
bands used by the one or more Wi-Fi and/or Bluetooth transceivers).
Thus, the paging signal and the power receiver/communication
circuits 125 and 135 of respective client devices 120 and 130 may
share an ISM band used by other transceivers of the respective
client devices 120 and 130.
[0031] In some implementations, the paging signal may not be
associated with any commercially available communication protocol
(such as Wi-Fi and Bluetooth communication protocols), but instead
may be based on a signaling technique independent of commercially
available communication protocols (such as a proprietary or
military communication protocol). In some implementations, the
paging signal may be transmitted on frequencies used by one or more
commercially available communication protocols. In some other
implementations, the paging signal may be transmitted on
frequencies different from the frequency bands used by commercially
available communication protocols. Example paging signals are
described in more detail below in conjunction with FIGS. 4A-4C.
[0032] FIG. 2 is a block diagram of an example host device 200. The
host device 200 may be an implementation of the host device 110 of
FIG. 1. The host device 200 may include antennas 201 and 202,
transceivers 210 and 211, a controller 240, and a memory 250.
Although two antennas and two transceivers are shown in the example
of FIG. 2, in other implementations, the host device 110 may
include any feasible number of antennas and transceivers. For
example, the host device 110 may include a single antenna and
transceiver, or may include three or more antennas and
transceivers. The transceiver 210 may be coupled directly or
indirectly to antenna 201, and the transceiver 211 may be coupled
directly or indirectly to antenna 202. The transceivers 210 and 211
may be implementations of the power transmitter and communication
circuit 115 of FIG. 1.
[0033] Transceiver 210 may transmit data to and receive data from
other wireless devices. For example, the transceiver 210 may
operate in accordance with the IEEE 802.11 family of standards, the
Bluetooth protocol, the Bluetooth Low Energy protocol, or any other
feasible communication protocol. In addition, the transceiver 210
may include an energy transmitter 215. The energy transmitter 215
may convert power from a local power source (such as a battery,
power supply, or the like, not shown for simplicity) into RF energy
that may be wirelessly transmitted to other devices via the antenna
201. The transmitted RF energy may be received by another wireless
device, and converted into power that may be used to power some or
all of the other wireless device. In a similar manner, the
transceiver 211 may also transmit and receive wireless data, and
may also include an energy transmitter 216 to transmit power (such
as described above with respect to the transmitter 215).
[0034] In some implementations, the transceivers 210 and 211 may
operate together to provide multiple-input multiple-output (MIMO)
and/or steered (beamformed) data communications. In a similar
manner, the energy transmitters 215 and 216 may operate together to
transmit steered (beamformed) power to other wireless devices.
[0035] The memory 250 may include a device ID storage 251 to store
one or more device IDs. In some implementations, a device ID may be
used as the target ID to identify one or more specific wireless
devices (such as the host device 200, the client devices 120 and/or
130). The device ID may be a MAC address, an IP address, or any
other number or value that may be associated with and/or used to
identify or address a particular wireless device.
[0036] Further, the memory 250 may include a non-transitory
computer-readable storage medium (such as one or more nonvolatile
memory elements, such as EPROM, EEPROM, Flash memory, a hard drive,
etc.) that may store the following software (SW) modules: [0037] a
communications control SW module 252 to control wireless
transmission and reception operations of the transceivers 210 and
211, for example, as described below for one or more operations of
FIG. 5; [0038] a beamforming SW module 253 to determine positions
of other wireless devices and direct the transceivers 210 and 211
to transmit beamformed data and/or RF energy pulses to the
determined positions, for example, as described below for one or
more operations of FIG. 5; and [0039] an energy transmitter SW
module 254 to manage operation of the energy transmitters 215 and
216, for example, as described below for one or more operations of
FIG. 5. In some implementations, one or more of the software
modules may be executed as a user application program. Each
software module includes program instructions that, when executed
by the controller 240, may cause the host device 200 to perform the
corresponding function(s). Thus, the non-transitory
computer-readable storage medium of memory 250 may include
instructions for performing all or a portion of the operations of
FIG. 5.
[0040] The controller 240, which may be coupled to the transceivers
210 and 211 and the memory 250, may be any one or more suitable
controllers or processors capable of executing scripts or
instructions of one or more software programs stored in the host
device 200 (e.g., within the memory 250). In some embodiments, the
controller 240 may be implemented with a hardware controller, a
processor, a state machine, or other circuits to provide the
functionality of the controller 240 executing instructions stored
in the memory 250.
[0041] The controller 240 may execute the communications control SW
module 252 to transmit and receive data via the transceivers 210
and 211. In some implementations, execution of the communications
control SW module 252 may enable the host device 200 to transmit
and receive data (including MIMO and beamformed data) to and from
other devices, and to transmit a non-beamformed paging signal
and/or a beamformed paging signal to a particular device (such as
one of the client devices 120 and 130) using the device IDs stored
in the device ID storage 251. In some implementations, execution of
the communications control SW module 252 may enable the host device
200 to receive a request from a client device to transmit RF
energy.
[0042] The controller 240 may execute the beamforming SW module 253
to determine locations of other wireless devices (such as the
client devices 120 and 130). Execution of the beamforming SW module
253 may also determine beamforming parameters (such as channel
coefficients and/or transceiver control settings) to transmit data
and/or paging signals as beamformed transmissions to the client
devices 120 and 130 via the transceivers 210 and 211. In some
implementations, execution of the beamforming SW module 253 may
cause one or more sounding packets (such as null data packets NDPs)
to be transmitted from the host device to one or both of the client
devices 120 and 130. In addition, execution of the beamforming SW
module 253 may enable analysis of feedback data (such as channel
state information sent in response to the sounding packets) from
other devices. The feedback data may be used to determine the
beamforming parameters (which may include a beamforming steering
matrix). In some implementations, the feedback data may also
include a request from a client device to transmit RF energy.
[0043] The controller 240 may execute the energy transmitter SW
module 254 to control the energy transmitters 215 and 216. In some
implementations, execution of the energy transmitter SW module 254
may cause the energy transmitters 215 and 216 to generate and
transmit one or more RF energy pulses (including RF pre-charging
pulses) to other devices. In some implementations, the RF energy
pulses may be beamformed and directed to particular client devices,
for example, based on their determined positions and using their
corresponding device IDs. In other implementations, the RF energy
pulses may not be beamformed but rather transmitted in multiple
directions. In some aspects, the RF energy pulses may be included
within a paging signal. In other aspects, the RF energy pulses may
be included within other suitable signals (such as unicast packets,
multi-cast packets, and/or broadcast packets).
[0044] FIG. 3 is a block diagram of an example client device 300.
The client device 300 may be an implementation of the client device
120 and/or the client device 130 of FIG. 1. The client device 300
may include antennas 301 and 302, transceivers 310 and 311, a power
combiner and storage unit 330, a controller 340, and a memory 350.
Although two antennas and two transceivers are shown in the example
of FIG. 3, in other implementations, the client device 300 may
include any feasible number of antennas and transceivers. The
transceiver 310 may be coupled directly or indirectly to the
antenna 301, and the transceiver 311 may be coupled directly or
indirectly to the antenna 302. The transceivers 310 and 311 may be
implementations of the power receiver/communication circuits 125
and 135 of respective client devices 120 and 130 of FIG. 1.
[0045] Similar to the transceivers 210 and 211 of FIG. 2, the
transceivers 310 and 311 may transmit and receive wireless data
from other wireless devices, including the host device 200. In
addition, the transceivers 310 and 311 may receive a paging signal
containing an encoded target ID that identifies or addresses the
client device 300. The transceiver 310 and/or the transceiver 311
may decode the target ID and provide the decoded target ID to the
controller 340. Upon reception of a paging signal addressed to the
client device 300 (which may be determined by comparing the decoded
target ID with a stored ID specific to the client device 300), the
transceiver 310 or 311 may assert a signal through the controller
340 that may be used to transition the client device from a first
operating state to a second operating state (such as from the low
power state to the active power state).
[0046] The transceiver 310 may include an adaptive matching unit
313 and an energy harvester 315. The energy harvester 315 may
receive RF energy from the adaptive matching unit 313, and convert
the RF energy into a power (voltage/current) to power, at least
partially, the client device 300. The adaptive matching unit 313
may be coupled to the antenna 301, and may be controlled at least
in part by the energy harvester 315. In some implementations, the
energy harvester 315 may sense a voltage (such as the average
voltage, the peak-to-peak voltage, or any other feasible voltage
measurement) from the antenna 301 and cause the adaptive matching
unit 313 to increase an amplitude of the RF signal provided to the
energy harvester 315, for example, to increase the amount of power
that may be converted by the energy harvester 315. In this manner,
received RF energy may be recovered from the RF pre-charging pulses
transmitted by the host device 200. Similarly, the transceiver 311
may include an adaptive matching unit 314 and an energy harvester
316 to receive RF energy from the antenna 302 and convert the RF
energy into power.
[0047] The power combiner and storage unit 330 may receive power
from the energy harvesters 315 and 316. The power combiner and
storage unit 330 may combine the power from the energy harvesters
315 and 316 to provide more voltage and/or current than may be
available from a single energy harvester. In some implementations,
the power combiner and storage unit 330 may accumulate power from
the energy harvesters 315 and 316. For example, the energy
harvesters 315 and 316 may harvest power from RF signals and may
accumulate the harvested power until power is needed by the client
device 300. In some other implementations, the power combiner and
storage unit 330 may include a battery to accumulate the harvested
power (battery not shown for simplicity). In this manner, the power
combiner and storage unit 330 may receive power from the energy
harvesters 315 and 316 to charge the included battery.
[0048] In some implementations, different energy harvesters may be
optimized to operate within different frequency ranges. For
example, the energy harvester 315 may be optimized to convert RF
energy within a 900 MHz frequency band, while the energy harvester
316 may be optimized to convert RF energy with the 2.4 GHz band.
The inclusion of multiple energy harvesters optimized for different
frequency bands may enable the client device 300 to more
efficiently convert RF energy into power from a wider range of
frequencies, for example, as compared with a client device that
includes only one energy harvester).
[0049] In some other implementations, the energy harvesters 315 and
316 may both be optimized to convert RF energy within the same
frequency band. For example, the energy harvesters 315 and 316 may
both be optimized to operate in the 2.4 GHz frequency band. The
location of the antennas 301 and 302 and/or the energy harvesters
315 and 316 may enable the energy harvesters 315 and 316 to receive
a correlated RF signal (based on wavelength and/or the relative
location of the RF transmitter). The energy harvesters 315 and 316
may generate power from the correlated RF signals, and the power
combiner and storage unit 330 may combine the generated power.
[0050] In another implementation, the energy harvesters 315 and 316
may be configured to receive different power levels of RF signals.
For example, the energy harvester 315 may be configured to receive
RF signals between -20 dBm and -30 dBm and the energy harvester 316
may be configured to receive signals between 0 dBm to -10 dBm. In
this manner, different energy harvesters may be used to receive
relatively strong RF signals and relatively weak RF signals. The
use of separate energy harvesters configured for different RF power
levels may involve a trade-off between sensitivity and circuit
complexity. For example, an energy harvester configured to receive
and convert relatively strong RF signals into power may have less
sensitivity than energy harvesters configured to receive and
convert relatively weak RF signals into power. In contrast, an
energy harvester configured to receive and convert relatively weak
RF signals into power may include additional circuitry to provide
protection from strong RF signals.
[0051] The memory 350 may include a device ID storage 351 to store
a device ID. In some implementations, a device ID may be used as a
target ID to identify a specific wireless device (such as the
client device 300). The device ID may be a MAC address, an IP
address, or any other number or value that may be associated with
and/or used to identify or address the client device 300.
[0052] Further, the memory 350 may include a non-transitory
computer-readable storage medium (such as one or more nonvolatile
memory elements, such as EPROM, EEPROM, Flash memory, a hard drive,
etc.) that may store the following software (SW) modules: [0053] a
communications control SW module 352 to control wireless
transmission and reception operations of the communication
transceivers 310 and 311, for example, as described below for one
or more operations of FIG. 6; [0054] a power combiner control SW
module 353 to control operation of the power combiner and storage
unit 330, for example, as described below for one or more
operations of FIG. 6; [0055] a beamformee SW module 354 to respond
to sounding packets received by the client device 300, for example,
as described below for one or more operations of FIG. 6; and [0056]
an adaptive matching SW module 355 to control operation of adaptive
matching units 313 and 314, for example, as described below for one
or more operations of FIG. 6.
[0057] The controller 340, which may be coupled to the transceivers
310 and 311, the power combiner and storage unit 330, and the
memory 350, may be any one or more suitable controllers or
processors capable of executing scripts or instructions of one or
more software programs stored in the client device 300 (e.g.,
within the memory 350). In some embodiments, the controller 340 may
be implemented with a hardware controller, a processor, a state
machine or other circuits to provide the functionality of the
controller 340 executing instructions stored in the memory 350.
[0058] The controller 340 may execute the communications control SW
module 352 to transmit and receive data via the transceivers 310
and 311. In some implementations, execution of the communications
SW module 352 may enable the client device 300 to transmit and
receive data (including MIMO and beamformed data) to and from other
devices, and to receive a paging signal (such as a paging signal
transmitted from the host device 110). In some implementations,
execution of the communication SW module 352 may enable the
controller 340 to compare the target ID encoded in the received
paging signal with the device ID stored in the device ID storage
351. If the target ID matches the device ID, then the controller
340 may assert a signal and transition the client device 300 from a
first operating state to a second operating state (such as from a
low power state to an active power state). Execution of the
communications SW module 352 may enable the client device 300 to
request a transmission of RF energy. For example, stored power in
the power combiner and storage unit 330 may be at a low level (a
level less than a threshold). In response, a request for a
transmission of RF energy may be transmitted to other devices, such
as the host device 200 of FIG. 2.
[0059] The controller 340 may execute the power combiner control SW
module 353 to cause or instruct the power combiner and storage unit
330 to combine and/or accumulate power (voltage and/or current)
provided from the energy harvesters 315 and 316. In some
implementations, execution of the power combiner control SW module
353 may cause or instruct the power combiner and storage unit 330
to accumulate power, for example, by charging a battery.
[0060] The controller 340 may execute the beamformee SW module 354
to respond to sounding packets and to provide feedback data that
may enable a host device to determine beamforming parameters
associated with the client device 300. In some implementations, the
beamforming parameters may enable the host device 110 to transmit
beamformed paging signals and/or data signals to the client device
300. In some aspects, the feedback data may include channel state
information from which the host device 110 may determine a
beamforming steering matrix. In some implementations, the feedback
data may include a request for a transmission of RF energy.
[0061] The controller 340 may execute the adaptive matching SW
module 355 to respond to RF signals received through one or both of
the antennas 301 and 302. Execution of the adaptive matching SW
module 355 may sense an amplitude of the received RF signal and
adjust one or more operating parameters (such as control voltages,
bias voltages, and the like) of the adaptive matching units 313 and
314 to increase a magnitude of the received RF signal. Increasing
the RF signal magnitude may increase an operating efficiency of
associated energy harvesters 315 and 316.
[0062] As described above with respect to FIGS. 1-3, a received RF
signal may include a paging signal. The paging signal may include
RF pre-charging pulses and data fields. The RF pre-charging pulses
may provide RF energy in advance of the data fields to enable the
energy harvester 315 and/or the energy harvester 316 to generate
power for at least a portion of the client device 300, for example,
to receive the data fields of the RF signal. Some example
implementations of paging signals are described below with respect
to FIGS. 4A-4C.
[0063] FIG. 4A is a diagram 400 depicting one implementation of a
paging signal 405 that may be transmitted by the host device 200 of
FIG. 2 to the client device 300 of FIG. 3. In some implementations,
the paging signal 405 may include one or more RF pre-charging
pulses 410 and a data field 411. Although only two RF pre-charging
energy pulses 410 are shown in the paging signal 405, in other
embodiments, the paging signal 405 may include any number of RF
pre-charging energy pulses. The RF pre-charging pulses 410 may
provide power for one or more portions of the client device 300.
The RF pre-charging pulses 410 may be transmitted during a first
time period (such as between times t.sub.0-t.sub.1).
[0064] In some aspects, the data field 411 may include an encoded
target ID and/or any other feasible data for transmission during a
second time period (such as between times t.sub.1-t.sub.2). In some
implementations, the data field 411 may be encoded via an on-off
keying (OOK) modulation technique. On-off keying uses the presence
and absence of RF energy to encode and transmit data. In some
aspects, the host device 110 may generate RF energy to indicate a
first logical state (e.g., a logical one), and may not generate RF
energy to indicate a second logical state (e.g., a logical zero).
In other aspects, the host device 110 may generate RF energy to
indicate a logical zero, and may not generate RF energy to indicate
a logical one. During the transmission of RF energy associated with
the paging signal 405, the host device 200 may not need to modulate
the transmitted RF energy according to Wi-Fi, Bluetooth, BLE, or
other communication protocols. Instead, the host device 200 may
transmit an unmodulated carrier signal within a frequency band from
which the client device 300 may detect a presence (or absence) of
RF energy.
[0065] As an example, the host device 200 may generate and transmit
RF energy via RF envelopes 412, 414, and 416. Using OOK, the RF
envelopes 412, 414, and 416 may represent logical ones, and a lack
of RF energy during periods or time slots 413 and 415 may represent
logical zeros. In other implementations, the RF envelopes 412, 414,
and 416 may represent logical zeros, and a lack of RF energy during
periods or time slots 413 and 415 may represent logical ones. In
the example of FIG. 4A, the RF envelopes 412, 414, and 416 may
encode a target ID of 101101.
[0066] In the example paging signal 405, the RF pre-charging pulses
410 and the data field 411 are illustrated as being transmitted at
the same power level. An average effective isotropic radiated power
(EIRP) of the paging signal 405, based on the transmit power level
of the RF pre-charging pulses 410 and the data field 411, may be
less than a regulatory limit. As illustrated in FIG. 4A, the paging
signal 405 may include discontinuous RF energy bursts. Thus, the RF
energy bursts may be interspersed with periods of no or relatively
low RF energy. This arrangement of RF energy bursts may enable the
peak-to-average power ratio of the paging signal 405 to be less
than the regulatory limit, although some portions of the paging
signal 405 may instantaneously exceed the regulatory limit.
[0067] In some implementations, the RF pre-charging pulses 410 may
be omitted from the paging signal 405, for example, leaving only
the data field 411 in the paging signal 405. The RF energy within
the data field 411 may be harvested and used to power the client
device 300 in a manner similar to the RF energy within the RF
pre-charging pulses 410. For example, the data field 411 may
include RF envelopes (RF energy) that encode a target ID. The data
field 411 (the target ID RF envelopes) may be received by, and
provide power for, the client device 300. The client device 300 may
also decode the data field 411 to receive the transmitted target
ID.
[0068] In some implementations, the RF pre-charging pulses 410 may
be transmitted in a different frequency band than the data field
411. For example, the RF pre-charging pulses 410 may be transmitted
within a 900 MHz frequency band, while the data field 411 may be
transmitted within a 2.4 GHz or 5 GHz frequency band. In this
manner, the propagation properties of a first frequency band may be
used to transmit power, while the propagation properties of a
second frequency band may be used to transmit data. Moreover,
transmitting the RF pre-charging pulses 410 and the data field 411
in different frequency bands may reduce interference of the data
field 411.
[0069] In some other implementations, the RF pre-charging pulses
410 and the data field 411 may be transmitted within a similar or
shared frequency band. In these other implementations, the antennas
and other RF components of the associated transceivers and energy
harvesters of a client device may be optimized for a single
frequency band and shared between the transceivers and the energy
harvesters.
[0070] In still other implementations, the RF pre-charging pulses
410 may be transmitted according to a first communication protocol,
and the data field 411 may be transmitted according to a second
communication protocol (different than the first communication
protocol). For example, the RF pre-charging pulses 410 may be
transmitted according to a Wi-Fi communication protocol, and the
data field 411 may be transmitted according to a Bluetooth
protocol. In this implementation, relatively high power RF
pre-charging pulses 410 may be transmitted to provide power to a
client device, while relatively lower power data fields 411 may be
used to transmit data to the client device.
[0071] FIG. 4B is a diagram 420 depicting another implementation of
a paging signal 425 that may be transmitted by the host device 200
of FIG. 2 to the client device 300 of FIG. 3. The paging signal 425
may include one or more RF pre-charging pulses 430 transmitted
during a first time period (between times t0-t1), and may include a
data field 431 transmitted during a second time period (between
times t1-t2). In some implementations, the data field 431 may
consist of continuous or relatively continuous RF energy
transmitted between times t1-t2. Although an increased amount of RF
energy may be transmitted (as compared to the paging signal 405 of
FIG. 4A), the transmit power of the paging signal 425 may be
selected to provide an average EIRP less than or equal to a
regulatory limit.
[0072] FIG. 4C is a diagram 440 depicting another implementation of
a paging signal 445 that may be transmitted by the host device 200
of FIG. 2 to the client device 300 of FIG. 3. The paging signal 445
may include one or more RF pre-charging pulses 450 transmitted
during a first time period (between times t0-t1), and may include a
data field 451 transmitted during a second time period (between
times t1-t2). The transmit power associated with the RF
pre-charging pulses 450 may be much greater (such as by more than a
threshold amount) than the transmit power associated with the data
field 451. In some implementations, the transmit power of the RF
pre-charging pulses 450 may exceed a regulatory limit or threshold.
However, by controlling a transmit duty cycle of the paging signal
445 (transmission times of RF pre-charging pulses 450 vs
transmission times of data fields 451), the overall EIRP of the
paging signal 445 may be maintained within regulatory limits. The
larger transmit power of the RF pre-charging pulses 450 (as
compared with the transmit power of the data fields 451) may enable
energy harvesters within the client device 300, such as the energy
harvesters 315 and 316 of FIG. 3, to convert and/or accumulate
power for the client device 300 prior to receiving the data fields
451. In some implementations, the peak-to-average power ratio of
the paging signal 445 may be less than the regulatory limit,
although some portions of the paging signal 445 may instantaneously
exceed the regulatory limit.
[0073] FIG. 5 is a flowchart depicting an example operation 500 for
operating a host device, in accordance with some embodiments.
Although described herein as being performed by the host device 200
of FIG. 2, the operation 500 may be performed by the host device
110 of FIG. 1, or by any other suitable device. The operation
begins as the host device 200 determines a location of a client
device and/or receives a request for RF energy (510). In some
implementations, the transceivers 210 and 211 of the host device
200 may transmit one or more sounding packets to determine the
location of the client device. The client device may use the
sounding packet to determine channel conditions or channel state
information (CSI), and send a feedback frame containing the
determined channel conditions or the CSI to the host device 200. In
some other implementations, the host device 200 may receive a
request for an RF energy transmission from a client device (such as
client device 300).
[0074] Next, the host device 200 determines beamforming parameters
based on the determined location of the client device (520). In
some implementations, the host device may determine the beamforming
parameters based on the received feedback frame, for example, to
determine a steering matrix that can be used to steer one or more
signals in the direction of the located client device. The
beamforming parameters may include phase and/or amplitude settings
for the transceivers 210 and 211, for example, to enable
constructive and destructive interference on signals transmitted by
the transceivers 210 and 211.
[0075] Next, the host device 200 operates an energy transmitter to
convert a local power source to RF energy (530). In some
implementations, the energy transmitter 215 or the energy
transmitter 216 may generate a paging signal, one or more
pre-charging pulses, and/or one or more data fields that may
include a target ID.
[0076] Next, the host device 200 transmits RF energy (540). In some
aspects, the RF energy provided by the energy transmitter 215
and/or the energy transmitter 216 may be transmitted by the
transceivers 210 and 211 in accordance with the beamforming
parameters determined at 520. In this manner, the RF energy may be
transmitted and steered towards one or more client devices (such as
in the direction of the located client devices). In some
implementations, the transmitted RF energy may not be beamformed.
Thus, operations 510, 520, and portions of 540 may be omitted to
transmit RF energy to one or more client devices. In some other
implementations, in response to a request for an RF energy
transmission, the host device 200 may transmit a modified paging
signal. The modified paging signal may be similar to the paging
signals 405, 425, and 445 of FIGS. 4A, 4B, and 4C respectively. For
example, the paging signals 405, 425, and 445 may be modified to
omit data and only include the pre-charging energy pulses 410, 430,
and 450 of FIGS. 4A-4C. In some other implementations, null data
(zero data) may be included in the data fields 411, 431, and 451.
In this manner, RF energy may be transmitted even when the paging
signals 405, 425, and 445 do not include data for any particular
client device.
[0077] FIG. 6 is a flowchart depicting an example operation 600 for
operating a client device, in accordance with some embodiments.
Although described herein as being performed by the client device
300 of FIG. 3, the operation 600 may be performed by the client
device 120 or the client device 130 of FIG. 1, or by any other
suitable device. The operation begins as the client device 300
receives one or more sounding packets from a host device (610).
Next, the client device 300 may transmit feedback data (such as
channel state information and/or feedback matrices) in response to
the received sounding packets (620). Information included in the
feedback data may enable the host device to determine a steering
matrix that can be used to transmit a beamformed RF signal toward
the client device 300. In some implementations, the feedback data
may include a request for an RF energy transmission.
[0078] Next, the client device 300 receives an RF signal (630). In
some implementations, the RF signal may be a paging signal
including one or more RF pre-charging pulses and data fields. Next,
the client device 300 may determine whether an amplitude of the
received RF signal can be increased (640). In some aspects, the
amplitude of the received RF signal may be increased by adjusting
one or both of the adaptive matching units 313 and 314. Increasing
the amplitude of the received RF signal may increase the efficiency
of one or both of the associated energy harvesters 315 and 316.
[0079] If the amplitude of the received RF signal can be increased,
then the client device 300 may adjust one or both of the adaptive
matching units 313 and 314 to increase the amplitude of the
received RF signal (650). In some implementations, the energy
harvester 315 and/or the energy harvester 316 may generate control
signals to increase the amplitude of the received RF signal. Next,
the client device 300 may operate one or both of the energy
harvesters 315 and 316 to convert the RF signal into power for the
client device 300 (660). If the amplitude of the RF signal cannot
be increased (as determined at 640), then the operation proceeds to
660 to operate one or both of the energy harvesters 315 and 316. In
some implementations, the client device 300 may optionally combine
and/or accumulate power from a plurality of energy harvesters using
the power combiner and storage unit 330.
[0080] In some implementations, responding to sounding packets
and/or increasing an amplitude of the received RF signal may be
optional operations. Thus, one or more operations 610, 620, 640, or
650 may be omitted, and an RF signal may be received at 630 and
converted into power at 660.
[0081] In the foregoing specification, the example embodiments have
been described with reference to specific exemplary embodiments
thereof. It will, however, be evident that various modifications
and changes may be made thereto without departing from the broader
scope of the disclosure as set forth in the appended claims. The
specification and drawings are, accordingly, to be regarded in an
illustrative sense rather than a restrictive sense.
* * * * *