Subscription based MISO and MIMO wireless energy transfer

• US 9,800,059 B2
• Filed: 09/19/2013
• Issued: 10/24/2017
• Est. Priority Date: 09/19/2012
• Status: Active Grant

• Current Assignee: Duke University
• Original Assignee: Duke University
• Inventors: Reynolds, Matthew, Arnitz, Daniel
• Primary Examiner(s): Chen, Sibin
• Application Number:
  US14/429,477
• Publication Number:
  US 20150229133A1
• Time in Patent Office: 1,496 Days
• CPC Class Codes: H02J 11/00 Circuit arrangements for providing service supply to auxiliaries of stations in which electric power is generated, distributed or converted
• CPC Class Codes: H02J 50/001 Energy harvesting or scavenging
• CPC Class Codes: H02J 50/20 using microwaves or radio frequency waves
• CPC Class Codes: H02J 50/40 using two or more transmitting or receiving devices H02J50/50 takes precedence
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04W 52/225 Calculation of statistics, e.g. average, variance
• CPC Class Codes: H04W 52/24 using SIR [Signal to Interference Ratio] or other wireless path parameters
• CPC Class Codes: H04W 52/245 taking into account received signal strength
• CPC Class Codes: H04W 52/246 where the output power of a terminal is based on a path parameter calculated in said terminal
• CPC Class Codes: H04W 52/281 taking into account user or data type priority

Abstract

Subscription based multiple-input-single-output and multiple-input-multiple-output wireless energy transfer enables selective charging and powering of mobile devices using a plurality of spatially distributed transmitters that are synchronized under the control of a transmitter controller. Amplitude, phase, and frequency of each transmitter is controlled to promote or deny the transfer of energy to particular mobile devices or positions through optimization techniques based on the incident power level at each mobile device subscribing to the system. Measurements related to the incident power level may be directly provided by the mobile device or the incident power is remotely determined through analysis of backscatter gains.

Claims

1. A subscription based MIMO radio-frequency energy transfer system, comprising:

one or more storage media having instructions stored thereon at least directing the system to;

determine a presence of one or more devices in an area, wherein the one or more devices derive at least part of their operating energy from incident radio-frequency energy;

verify that the one or more devices are subscribed devices; and

transfer radio-frequency energy to the one or more subscribed devices according to a power level representing radio-frequency energy incident upon the subscribed devices;

a plurality of transmitters;

a transmitter controller for controlling the plurality of transmitters, the transmitter controller configured to adjust an amplitude and phase of each transmitter of the plurality of transmitters for transferring the energy to the subscribed devices; and

a plurality of receivers and a receiver processor configured to at least combine signals from the plurality of receivers.

2. The system of claim 1, wherein the plurality of transmitters are spatially dispersed around the area.

3. The system of claim 2, wherein the one or more devices comprise at least two devices independently moving within and out of the area.

4. The system of claim 1, wherein the transmitter controller is further configured to select a subset of the plurality of transmitters to transfer the energy to the subscribed devices, the subset selected according to radio-frequency channel information of the subscribed devices.

5. The system of claim 4, wherein the subset of the plurality of transmitters comprise at least two transmitters with a maximum channel gain to the subscribed devices.

6. The system of claim 1, wherein the one or more storage media have instructions stored thereon at least directing the system to further:

determine an optimized set of transmitter amplitudes (|A|) and phases (∠

A) using information about the power level received from the subscribed devices, the optimized set being used by the transmitter controller to adjust the amplitude and phase of the plurality of transmitters.

7. The system of claim 1, wherein the one or more storage media have instructions stored thereon at least directing the system to further:

determine an optimized set of transmitter amplitudes (|A|) and phases (∠

A) using information about the power level obtained from a backscatter signal of the subscribed devices received from the plurality of receivers, the optimized set being used by the transmitter controller to adjust the amplitude and phase of the plurality of transmitters.

8. The system of claim 7, wherein using the information about the power level obtained from the backscatter signal of the subscribed devices received from the plurality of receivers comprises:

optimizing a receiver power level representing energy of the backscatter signal of each of the subscribed devices incident upon the plurality of receivers.

9. The system of claim 7, wherein using the information about the power level obtained from the backscatter signal of the subscribed devices received from the plurality of receivers comprises:

generating a backscatter gain matrix from the backscatter signal of each of the subscribed devices received from the plurality of receivers;

performing a decomposition of the backscatter gain matrix to generate an autocovariance matrix, and

solving the autocovariance matrix for channel gain and phase.

10. The system of claim 1, wherein in response to a plurality of subscribed devices being determined to be in the area, the system maximizes the total energy transferred to all the subscribed devices.

11. The system of claim 10, wherein each device is assigned a designated frequency range at which the energy is transferred.

12. The system of claim 1, wherein the one or more storage media have instructions stored thereon at least directing the system to further identify a blocked device in the area and actively deny power to the blocked device,

wherein the transmitter controller is further configured to adjust amplitudes and phases of the plurality of transmitters to minimize energy incident upon the blocked device.

13. The system of claim 1, wherein the radio-frequency energy is transferred to at least one subscribed device of the one or more subscribed devices at a first frequency, the transmitter controller being further configured to adjust amplitudes and phases of the plurality of transmitters to minimize energy incident upon the at least one subscribed device at a second frequency while maximizing energy incident the at least one subscribed device at the first frequency.

14. The system of claim 13, wherein the second frequency is a frequency in a communication frequency range of the at least one subscribed device.

15. The system of claim 1, wherein the radio-frequency energy is transferred to at least one subscribed device of the one or more subscribed devices such that maximum available energy is transmitted to each of a plurality of antennas of the at least one subscribed device.

16. The system of claim 1, wherein the radio-frequency energy is transferred to the subscribed devices such that maximum available energy is transmitted to at least one subscribed device of the one or more subscribed devices and an area extending a distance around the at least one subscribed device.

17. One or more storage media having instructions stored thereon for performing a method of subscription based MIMO radio-frequency energy transfer comprising:

determining a presence of a device in an area;

verifying that the device is a subscribed device; and

transferring radio-frequency energy from a MIMO system to the subscribed device according to a power level representing radio-frequency energy incident the subscribed device wherein the power level is determined by the system by;

analyzing backscatter signals received by a plurality of receivers associated with the MIMO system to generate a backscatter gain matrix; and

performing channel decorrelation of the backscatter gain matrix to obtain a total power level (P_Avm).

18. The one or more storage media of claim 17, wherein the power level is the total power level (P_Avm) given by

19. The one or more storage media of claim 18, wherein the channel gain c_lm,k is received from the mobile device m.

20. The one or more storage media of claim 18, wherein a carrier amplitude and phase |a_l,k|e^J∠

a^l,kc_lm,k is received from the mobile device m.

21. The one or more storage media of claim 18, wherein a power per frequency component

22. The one or more storage media of claim 18, wherein the total power level is received from the mobile device m.

23. One or more storage media having instructions stored thereon for performing a method of subscription based MIMO radio-frequency energy transfer comprising:

determining a presence of a device in an area;

verifying that the device is a subscribed device; and

transferring radio-frequency energy from a MIMO system to the subscribed device according to a power level representing radio-frequency energy incident the subscribed device, wherein the power level is given by;

24. A method of subscription based MIMO wireless energy transfer, the method comprising:

determining a presence of a mobile device wherein the mobile device derives at least part of its operating energy from incident wireless energy;

determining whether the mobile device is a subscriber or a blocked device;

in response to a determination that the mobile device is the subscriber, optimizing a gain and phase of a plurality of transmitters to enable maximum energy transfer to the mobile device;

in response to a determination that the mobile device is the blocked device, optimizing a gain and phase of a plurality of transmitters to enable minimum possible energy transfer to the mobile device;

determining whether a backscatter gain or an estimated backscatter gain of the mobile device is available to the MIMO system;

generating a channel gain matrix from backscatter signals received by the MIMO system;

decorrelating the channel gain matrix using the backscatter gain or the estimated backscatter gain to determine the power level; and

using the power level to optimize the gain and phase of the plurality of transmitters.

25. The method of claim 24, further comprising:

in response to receiving a power level signal from the mobile device, using the power level signal to optimize the gain and phase of the plurality of transmitters.

26. The method of claim 24, further comprising:

determining a received power level from backscatter signals received by receivers of the MIMO system; and

using the received power level to optimize the gain and phase of the plurality of transmitters.

27. The method of claim 24, wherein optimizing the gain and phase of the plurality of transmitters comprises solving a maximum or a minimum of a cost function with constraints on amplitude normalization, magnitude of the amplitude, and the phase.

28. The method of claim 27, wherein the cost function comprises a combination function such as minimizing peak power, minimizing average power, maximizing average power, or minimizing minimum power, subject to constraints derived at least in part from an economic aspect of the subscription.