System and method for signals transmission in complex scattering environments using interaction of the waves with a nonlinear object

• US 9,424,665 B1
• Filed: 01/06/2014
• Issued: 08/23/2016
• Est. Priority Date: 01/04/2013
• Status: Active Grant

• Current Assignee: University of Maryland
• Original Assignee: University of Maryland
• Inventors: Frazier, Matthew, Taddese, Biniyam TesFaye, Anlage, Steven Mark
• Primary Examiner(s): Ratcliffe, Luke
• Assistant Examiner(s): Baghdasaryan, Hovhannes
• Application Number:
  US14/147,993
• Time in Patent Office: 960 Days
• US Class Current: 1/1
• CPC Class Codes: G01S 7/52038 involving non-linear properties of the propagation medium or of the reflective target
• CPC Class Codes: G01S 7/52046 Techniques for image enhancement involving transmitter or receiver image enhancement by image data processing G06T5/00
• CPC Class Codes: G01S 7/52049 using correction of medium-induced phase aberration
• CPC Class Codes: G01V 2210/588 Non-linear media
• CPC Class Codes: G06T 11/005 Specific pre-processing for tomographic reconstruction, e.g. calibration, source positioning, rebinning, scatter correction, retrospective gating
• CPC Class Codes: H04K 1/00 Secret communication
• CPC Class Codes: H04K 1/06 by transmitting the information or elements thereof at unnatural speeds or in jumbled order or backwards
• CPC Class Codes: H04K 2203/12 for acoustic communication
• CPC Class Codes: H04K 2203/14 for the transfer of light or images, e.g. for video-surveillance, for television or from a computer screen
• CPC Class Codes: H04K 2203/16 for telephony
• CPC Class Codes: H04K 2203/24 for communication related to weapons
• CPC Class Codes: H04K 3/43 characterized by the control of the jamming power, signal-to-noise ratio or geographic coverage area
• CPC Class Codes: H04K 3/46 characterized in that the jamming signal is produced by retransmitting a received signal, after delay or processing
• CPC Class Codes: H04K 3/62 by exposing communication, processing or storing systems to electromagnetic wave radiation, e.g. causing disturbance, disruption or damage of electronic circuits, or causing external injection of faults in the information
• CPC Class Codes: H04K 3/68 using passive jamming, e.g. by shielding or reflection shielding of apparatus or components against electric or magnetic field H05K9/00
• CPC Class Codes: H04K 3/825 by jamming
• CPC Class Codes: H04K 3/92 related to allowing or preventing remote control

Abstract

A system and method for safe communication in a complex scattering environment is achieved by means of providing a passive nonlinear object in the wave propagation environment which nonlinearly interacts with the waves to create an exclusive communication channel between the nonlinear object and any point where the waves can be collected. Excitations generated by the nonlinearity in the time-reversal mirror are gathered, time-reversed, and retransmitted into the environment. The retransmitted signals arrive and are reconstructed exclusively at the location of the nonlinear object or linear object depending on the linearity or nonlinearity of the retransmitted sonas. The principles of the system and method are useful in numerous applications where signal communication or power delivery is desired to an object whose location is not known or dynamically changed in an exclusive, highly localized, precise, and secure fashion.

Claims

1. A method of signal transmission in wave propagating environments, comprising the steps of:

(a) exposing at least one non-linear object to waves propagating in a wave propagating environment of interest, thereby causing generation of intermodulation product signals originating at said at least one nonlinear object and propagating to a receiving port provided in said wave propagating environment of interest, and establishing a linear port in said wave propagating environment of interest for transmission of said waves into said wave propagating environment of interest;

(b) detecting at said receiving port a full sona signal including at least one nonlinear sona corresponding to said intermodulation product signals, and a linear sona corresponding to said waves reverberating in said waves propagating environment of interest;

(c) extracting said at least one nonlinear sona and said linear sona from said full sona signal at said receiving port;

(d) time-reversing said linear and nonlinear sonas; and

(e) transmitting said time-reversed at least one nonlinear sona and said time-reversed linear sona from said receiving port into said wave propagating environment of interest, wherein said time-reversed at least one nonlinear sona propagates in said wave propagating environment of interest to, and reconstructs exclusively at a location of said at least one nonlinear object, thus producing a nonlinear time-reversed signal, thereby establishing an exclusive wave-enabled communication channel between said at least one nonlinear object and said receiving port, and

wherein said time-reversed linear sona reconstruct exclusively at said linear port, thus obtaining a linear time-reversed signal exclusively at a location of said linear port.

2. The method of claim 1, further comprising the steps of:

in said step (a), exposing said at least one nonlinear object to pulsed said waves propagating in the wave propagating environment of interest, thereby inducing a pulsed nonlinear response of said at least one nonlinear object, including pulsed harmonic signals,

in said step (b), detecting at said receiving port said full sona including said intermodulation product and/or said pulsed harmonic signals, and

in said step (e), reconstructing time-reversed said pulsed harmonic signals.

3. The method of claim 1, further comprising the steps of:

in said step (b), applying a Fast Fourier transform computation to said detected full sona signal,

wherein the Fast Fourier Transform results in combination of signals at a wave frequency f_pulse, harmonic frequency f_nonlinear of the excitations of said at least one nonlinear object, and signals at intermodulation frequencies, including f_pulse+f_nonlinear.

4. The method of claim 3, further comprising the steps of:

in said step (c), applying a band-pass filter centered at said intermodulation frequencies, including f_pulse+f_nonlinear, to said full sona signal to extract said nonlinear sona therefrom.

5. The method of claim 2, further comprising the steps of:

in said step (c), applying a bandpass filter centered at said harmonic frequency f_nonlinear to said full sona to extract said nonlinear time-reverse pulsed harmonic signals.

6. The method of claim 1, further comprising the steps of:

in said step (c), applying a band-pass filter centered at a wave frequency f_pulse to said full sona signal to extract said linear sona therefrom.

7. The method of claim 1, further comprising the steps of:

after said step (c), applying a pulse code modulation to said nonlinear sona received through the steps of;

(f) assigning a 1 bit value to said non-linear sona received at said receiving port, thereby creating a 1 bit sona,

(g) creating a 0 bit sona from said nonlinear sona received at said receiving port,

(h) creating a coded message including a series of said 1 bit sonas and said 0 bit sonas interposed in a predetermined sequence,

(i) in said step (e), transmitting said coded message from said receiving port into said waves propagating environment of interest,

(j) detecting presence and absence of reconstructed nonlinear time-reversed signals at said at least one nonlinear object, wherein said 1 bit sonas are detected at said at least one nonlinear object, and wherein said 0 bit sonas are not reconstructed at said at least one nonlinear object,

(k) detecting non-linear time-reversed signals, and

(l) decoding said detected nonlinear time-reversed signals.

8. The method of claim 7, further comprising the steps of:

in said step (g), applying Fast Fourier Transform to said nonlinear sona, thereby transforming said nonlinear sona into the frequency domain,

adding a random Gaussian noise to the phase information of said nonlinear sona in frequency domain, thereby creating a noisy-phase signal, and

applying an Inverse Fast Fourier transform to said noisy-phase signal to transform said noisy-phase signal into the time domain.

9. The method of claim 1, further comprising the steps of:

after said step (c), encoding an image by means of said nonlinear sona, and

in said step (e), broadcasting said encoded image into said wave propagating environment of interest, thereby directing said image to be reconstructed exclusively at the location of said at least one nonlinear object.

10. The method of claim 1, further comprising the steps of:

after said step (c), encoding an image by means of said linear sona, and

in said step (e), broadcasting said encoded image into said wave propagating environment of interest, thereby directing said image to be reconstructed exclusively at the location of said linear port.

11. The method of claim 1, further comprising the steps of:

after said step (b), establishing the presence of said at least one nonlinear object in said wave propagating environment of interest if frequency components outside the said wave bandwidth are detected,

in said step (d), time-reversing and amplifying said frequency components originating from said at least one nonlinear object, and

in said step (e), reconstructing said amplified time-reversed signal at said at least one nonlinear object, thereby affecting the operation mode thereof.

12. The method of claim 1, wherein said wave propagating environment of interest is a biological system, further comprising the steps of:

prior to said step (a), introducing non-linear substances having non-linear dynamics to a biological system, wherein said nonlinear substances are bio-chemically directed to and accumulating at a location of interest in said biological system, and

in said steps (d) and (e), time reversing said at least one non-linear sona received from said non-linear substances, and transmitting said time-reversed at least one non-linear sona into said biological system to be reconstructed exclusively at said location of interest.

13. The method of claim 12, wherein said location of interest contains a tumor, and wherein said at least one time-reversed non-linear sona includes a radiation wave capable of destroying tissues of the tumor.

14. The method of claim 1, further comprising the steps of:

in a wireless power transfer system, providing a nonlinear tag at a receiving antenna of an object to receive power,

coupling a power source to said receiving port, and

in said step (e), transmitting power from said power source to said receiving antenna through an exclusive communication channel established between said nonlinear tag and said power source using said nonlinear time-reversed signal.

15. The method of claim 1, wherein said waves include either of electromagnetic, acoustic, seismic, quantum mechanical, and biological waves.

16. The method of claim 1, wherein said at least one non-linear object includes either of diodes, transistors, electrostatic-discharge diodes, metal-insulator-metal junctions, active circuits (electromagnetic), cracks (acoustic), geological faults, mineral and petroleum deposits (seismic), or superconductors, superfluids, p/n junctions, quantum dots, nanoparticles (quantum mechanical), magnetic particles, biological, and bio-chemical substances.

17. A system for signal transmission in wave propagating environments, comprising:

a waves propagating environment of interest,

a receiving port in said waves propagating environment of interest,

at least one non-linear object exposed to said waves in said waves propagating environment of interest and producing intermodulation product or harmonic signals originating thereat and propagating to said receiving port,

a linear source of waves,

a signal detector coupled to said receiving port and configured to detect a full sona signal including at least one non-linear sona corresponding to said intermodulation product and/or harmonic signals and a linear sona corresponding to said waves reverberating in said waves propagating environment of interest,

a first bandpass filter centered at frequencies of said intermodulation product or harmonic signals, and applied to said full sona to extract at least one nonlinear sona therefrom,

a second bandpass filter centered at frequencies of said waves and applied to said full sona to extract a linear sona therefrom,

a time-reversing unit coupled to said receiving port and configured to apply time-reversion routine to said at least one nonlinear sona, and

a transmitter coupled to said receiving port and said time-reversing unit and configured to transmit said time-reversed at least one nonlinear sona into said waves propagation environment of interest, wherein said transmitted time-reversed at least one nonlinear sona propagates towards a location of said at least one nonlinear object and reconstructs exclusively thereat, thus attaining an exclusive communication channel extending between said at least one nonlinear object and said receiving port,

wherein said linear sona is time-reversed in said time-reversing unit, and transmitted by said transmitter into said waves propagating environment, and wherein said time-reversed linear sona reconstruct exclusively at a location of said linear source of waves.

18. The system of claim 17, wherein said waves propagating environment included pulsed waves, wherein said at least one nonlinear object, being exposed to said pulsed waves, produces pulsed harmonic signals, and

wherein said nonlinear pulsed time-reversed harmonic signals reconstruct exclusively at said location of said at least one nonlinear object.

19. The system of claim 17, further including a processor unit operatively coupled to said receiving port and configured to apply a pulse code modulation routine to said at least one nonlinear sona,

said pulse code modulation routine being configured to:

create a 1 bit sona from said at least one nonlinear sona received at said receiving unit;

to create a 0 bit sona by applying a Fast Fourier transform to thereby transforming said nonlinear sona into the frequency domain,

adding a random Gaussian noise to the phase information of said nonlinear sona in frequency domain, thereby creating a noisy-phase signal, and

applying an Inverse Fast Fourier transform to said noisy-phase signal to transform the same into the time domain; and

creating, by said processor unit, an encoded message including a series of said 1 bit sonas and 0 bit sonas interposed in a predetermined sequence;

wherein said transmitter is configured to transmit said encoded message from said receiving port into said waves propagating environment of interest; and

wherein said processor unit is further configured to;

measure the reconstructed nonlinear time-reversed signals at the location of said at least one nonlinear object, wherein said 1 bit sonas are detected at said at least one nonlinear object, and wherein said 0 bit sonas are not reconstructed at said at least one nonlinear object, and

to decode said measured reconstructed nonlinear time-reversed signals.

20. The system of claim 17, further including:

an image source,

a processor unit operatively coupled to said image source and said receiving port and configured for encoding said image by said nonlinear sona,

wherein said transmitter unit is coupled to said processing unit to broadcast time-reversed said encoded image into said wave propagating environment of interest, thereby directing said time-reversed encoded image for reconstruction exclusively at said at least one nonlinear object.

21. A system of claim 17, wherein said at least one nonlinear object is a nonlinear substance compatible with biological environment and bio-chemically directed and accumulated at a location of interest in said waves propagating environment of interest, and

wherein said time-reversed nonlinear sona includes radiation waves capable of destroying biological tissues exclusively at said location of interest.