High bit-rate magnetic communication

• US 9,853,837 B2
• Filed: 04/01/2015
• Issued: 12/26/2017
• Est. Priority Date: 04/07/2014
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Krause, James Michael, Manickam, Arul
• Primary Examiner(s): Washburn, Daniel
• Assistant Examiner(s): HAILEGIORGIS, FITWI Y
• Application Number:
  US14/676,740
• Publication Number:
  US 20150326410A1
• Time in Patent Office: 1,000 Days
• Field of Search: 375295, 375219, 375259, 375316, 455411, 324322, 324225
• CPC Class Codes: H04B 5/24 Inductive coupling
• CPC Class Codes: H04L 25/0266 Arrangements for providing Galvanic isolation, e.g. by means of magnetic or capacitive coupling
• CPC Class Codes: H04L 25/05 Electric or magnetic storage of signals before transmitting or retransmitting for changing the transmission rate

Abstract

A magnetic communications transmitter includes a magnetic field generator and a controller. The magnetic field generator is configured to generate a magnetic field. The controller is configured to control the magnetic field generator by controlling an electrical current supplied to the magnetic field generator, and causing the magnetic field generator to generate an optimized variable amplitude triangular waveform.

Claims

1. A magnetic communications transmitter, the transmitter comprising:

a magnetic field generator configured to generate a vector magnetic field; and

a controller configured to control the magnetic field generator,

wherein;

controlling the magnetic field generator comprises;

controlling an electrical current supplied to the magnetic field generator, and

causing the magnetic field generator to generate an optimized variable amplitude triangular waveform,

wherein the controller is configured to encode active channel information in a portion of the generated vector magnetic field by modulating an amplitude of the optimized variable amplitude triangular waveform to form a MAX and an OFF symbol, the active channel information utilized by a receiver to determine an angle of arrival for the generated vector magnetic field and to demodulate the vector magnetic field by using a vector indicated by the MAX and OFF symbol of the active channel information of the optimized variable amplitude triangular waveform.

2. The transmitter of claim 1, wherein the optimized triangular waveform comprises a coherent amplitude modulated triangular waveform.

3. The transmitter of claim 1, wherein the transmitter is configured to transmit magnetic data packets, wherein each magnetic data packet comprises data portions and auxiliary portions.

4. The transmitter of claim 3, wherein the data potions comprises data symbols comprising amplitude modulated triangular waveforms, wherein the auxiliary portions comprise MAX and OFF symbols.

5. The transmitter of claim 4, wherein the transmitter is configured to transmit, during MAX symbols, a highest magnetic data symbol, to enable synchronization and calibration of a received signal at a receiver.

6. The transmitter of claim 4, wherein the transmitter is configured to transmit, during the OFF symbols, no data symbol to allow synchronization and background measurement at a receiver, wherein the background measurement enables the receiver to perform motion compensation, and wherein the motion compensation includes compensation for rotations in Earth'"'"'s magnetic field.

7. The transmitter of claim 1, wherein the transmitter is configured to enable simultaneous multiple channel communication.

8. The transmitter of claim 7, wherein the simultaneous multiple channel communication is enabled by the encoding of active transmitting channel information in MAX symbols of transmitted magnetic data packets.

9. A magnetic communications receiver, the receiver comprising:

a magnetic field sensor configured to sense a modulated magnetic field comprising multiple channels; and

a signal processor configured to demodulate each channel of the multiple channels of the sensed modulated magnetic field,

wherein;

each channel of the modulated magnetic field comprises an optimized variable amplitude triangular waveform, the magnetic field sensor detecting a direction of a polarization of a B-field vector corresponding to a channel for a transmitter using a transmitted MAX and OFF symbol of the modulated magnetic signal, the signal processor configured to demodulate the channel of the sensed modulated magnetic field using the detected direction.

10. The receiver of claim 9, wherein the magnetic field sensor comprises a diamond nitrogen-vacancy (DNV) sensor.

11. The receiver of claim 9, wherein the receiver is configured to decode magnetic data packets including magnetic data symbols, OFF symbols, and MAX symbols, and wherein the signal processor is configured to demodulate the magnetic data symbol including coherent amplitude modulated triangular waveform.

12. The receiver of claim 11, wherein the receiver is configured to measure background during OFF symbols, wherein the receiver is configured to leverage the background measurement to compensate for rotations in Earth'"'"'s magnetic field.

13. The receiver of claim 9, wherein the receiver is configured to perform synchronization and calibration during MAX symbols.

14. The receiver of claim 9, wherein the receiver is configured to retrieve data from simultaneous multiple channel communication.

15. The receiver of claim 14, wherein the receiver is configured to decode active transmitting channel information of multiple channel communication using information in MAX symbols of transmitted magnetic data packets.

16. A method for facilitating magnetic communications, the method comprising:

providing a magnetic field generator configured to generate a magnetic field; and

providing a controller configured to control the magnetic field generator,

wherein;

the controller is configured to;

control an electrical current supplied to the magnetic field generator, and

cause the magnetic field generator to generate an optimized variable amplitude triangular waveform,

wherein the controller is configured to encode active channel information in a portion of the generated vector magnetic field by modulating an amplitude of the optimized variable amplitude triangular waveform to form a MAX and an OFF symbol, the active channel information utilized by a receiver to determine an angle of arrival for the generated vector magnetic field and to demodulate the vector magnetic field by using a vector indicated by the MAX and OFF symbol of the active channel information of the optimized variable amplitude triangular waveform.

17. The method of claim 16, wherein the optimized variable amplitude triangular waveform comprise magnetic data symbols, wherein the magnetic data symbols are included in magnetic data packets further including MAX and OFF symbols.

18. The method of claim 17, further comprising transmitting, during the MAX symbols, a highest magnetic data symbol, to enable synchronization and calibration of a received signal at a receiver.

19. The method of claim 17, further comprising:

during the MAX symbols, transmitting a highest magnetic data symbol, to enable synchronization and calibration of a received signal at a receiver; and

during the OFF symbols, transmitting no data symbol to allow synchronization and background measurement at a receiver, wherein the background measurement enables the receiver to perform motion compensation, and wherein the motion compensation includes compensation for rotations in Earth'"'"'s magnetic field.

20. The method of claim 16, further comprising enabling simultaneous multiple channel communication, wherein the simultaneous multiple channel communication is enabled by the encoding of active transmitting channel information in MAX symbols of transmitted magnetic data packets.