Real-time wireless power transfer control for passive backscattering devices
First Claim
1. A wireless power distribution system comprising:
- an RF-energy harvesting sensor tag operable to generate a first backscatter signal; and
at least one base station operable to deliver RF power to the sensor tag by emitting a first waveform comprising a plurality of subcarriers in an RF channel,wherein the first backscatter signal is generated by the sensor tag by modulated scattering of the first waveform as incident upon the sensor tag,and further wherein the at least one base station controls energy harvested by the sensor tag by subsequently emitting a second waveform determined at least in part by a closed-loop feedback control algorithm responsive to measurements of the first backscatter signal, where the at least one base station selects the second waveform to compensate for impairments in the RF channel so that the sensor tag receives an incident waveform as a result of the emitted second waveform, the incident waveform substantially resembling the first waveform as emitted by the at least one base station prior to selecting the second waveform.
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Accused Products
Abstract
A method and apparatus is disclosed herein for real-time wireless power transfer control. In one embodiment, a system comprises: an RF-energy harvesting sensor tag operable to generate a first backscatter signal and at least one base station operable to deliver RF power to the sensor tag by emitting a first waveform comprising a plurality of subcarriers, wherein the first backscatter signal is generated by the sensor tag by modulated scattering of the first waveform as incident upon the sensor tag, and further wherein the at least one base station subsequently emits a second waveform determined at least in part by a closed-loop feedback control algorithm responsive to measurements of the first backscatter signal.
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Citations
19 Claims
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1. A wireless power distribution system comprising:
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an RF-energy harvesting sensor tag operable to generate a first backscatter signal; and at least one base station operable to deliver RF power to the sensor tag by emitting a first waveform comprising a plurality of subcarriers in an RF channel, wherein the first backscatter signal is generated by the sensor tag by modulated scattering of the first waveform as incident upon the sensor tag, and further wherein the at least one base station controls energy harvested by the sensor tag by subsequently emitting a second waveform determined at least in part by a closed-loop feedback control algorithm responsive to measurements of the first backscatter signal, where the at least one base station selects the second waveform to compensate for impairments in the RF channel so that the sensor tag receives an incident waveform as a result of the emitted second waveform, the incident waveform substantially resembling the first waveform as emitted by the at least one base station prior to selecting the second waveform. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for delivering power to an RF-energy harvesting backscatter sensor tag, the method comprising:
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transmitting, using a transmitter of a base station, a first waveform in an RF channel; measuring, using a receiver of the base station, a backscattered signal from the sensor tag, the backscattered signal resulting from the sensor tag performing modulated scattering of the first waveform as incident upon the sensor tag; computing adjustments to the first waveform based on measurements of the backscattered signal to compensate for impairments in the RF channel and applying the adjustments to create a second waveform; and transmitting the second waveform to the sensor tag so that the sensor tag receives an incident waveform as a result of the transmitted second waveform, the incident waveform substantially resembling the first waveform as transmitted by the base station prior to creating the second waveform. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. An article of manufacture having one or more recordable media storing instructions thereon which when executed by a system cause the system to perform a method for delivering power to an RF-energy harvesting backscatter sensor tag, the method comprising:
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transmitting, using a transmitter of a base station, a first waveform in an RF channel; measuring, using a receiver of the base station, a backscattered signal from the sensor tag, the backscattered signal resulting from the sensor tag performing modulated scattering of the first waveform as incident upon the sensor tag; computing adjustments to the first waveform based on measurements of the backscattered signal to compensate for impairments in the RF channel and applying the adjustments to create a second waveform; and transmitting the second waveform to the sensor tag so that the sensor tag receives an incident waveform as result of the transmitted second waveform, the incident waveform substantially resembling the first waveform as transmitted by the base station prior to creating the second waveform.
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19. A base station for use in a communication system having at least one RF harvesting backscatter sensor tag, the base station comprising:
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a transmitter to transmit a first waveform and a second waveform; a receiver to receive a backscattered signal from the sensor tag, the backscattered signal resulting from the sensor tag performing modulated scattering of the first waveform; a measurement unit coupled to the receiver to obtain measurements of the backscattered signal; a memory coupled to the measurement unit to store the measurements; and a controller, coupled to the memory, the transmitter, the receiver and the measurement unit, to compute adjustments to the first waveform based on the measurements of the backscattered signal and to cause the transmitter to transmit the second waveform to the sensor tag, the second waveform representing the first waveform with the adjustments applied thereto, so that the sensor tag receives an incident waveform as a result of the transmitted second waveform, the incident waveform substantially resembling the first waveform as transmitted by the base station prior to computing adjustments to the first waveform.
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Specification