Methods and systems for wireless communication by magnetic induction

• US 7,831,205 B2
• Filed: 06/15/2007
• Issued: 11/09/2010
• Est. Priority Date: 01/16/2007
• Status: Expired due to Fees

• Current Assignee: Utah State University
• Original Assignee: Utah State University
• Inventors: Shenai, Krishna, Jack, Nathan
• Primary Examiner(s): Anderson; Matthew D
• Assistant Examiner(s): GONZALES, APRIL GUZMAN
• Application Number:
  US11/763,961
• Publication Number:
  US 20080171512A1
• Time in Patent Office: 1,243 Days
• Field of Search: 455/41.1, 455/40, 455/41.2, 324/3, 324/6, 324/452, 324/457, 324/67, 324/662, 324/671, 324/674, 324/335, 324/72, 166/248, 166/64, 166/261, 166/258, 136/244, 136/246, 136/255, 136/263, 250/307, 331/40, 331/25, 331/37, 365/66, 365/226, 365/52
• US Class Current: 455/40
• CPC Class Codes: H04B 5/48 Transceivers

Abstract

Disclosed are embodiments of methods and systems for wireless data transmission by magnetic induction. In one embodiment, a network of magnetic induction units is provided. The units may be configured to transmit a data signal by modulation of a time-varying magnetic field. One or more units may also be configured to receive a data signal received from another magnetic induction unit. In one specific implementation, a network of underground magnetic induction units is provided, each having a sensor connected thereto. Each of the units, or a subset of the units, may be configured to transmit its sensed data to an adjacent or nearby unit, which, in turn, may retransmit the original data, along with additional appended data, to another adjacent unit. The network data may thereby be relayed in a multi-hop fashion until it reaches a desired destination.

Claims

1. A system for wireless data transmission by magnetic induction, the system comprising:

a first magnetic induction unit configured to transmit a first data signal by modulation of a time-varying magnetic field, wherein the first magnetic induction unit is positioned within a non-gaseous substance, and wherein the first magnetic induction unit comprises an onboard power source;

a first sensor, wherein the data contained in the first data signal is obtained from the first sensor;

a second magnetic induction unit configured to receive the first data signal from the first magnetic induction unit and configured to transmit a second data signal wherein the second data signal comprises data from the first data signal, and;

a second sensor operatively connected with the second magnetic induction unit wherein the second data signal further comprises appended data received from the second sensor.

2. The system of claim 1, wherein the first magnetic induction unit comprises a first single ferromagnetic coil configured to transmit the data signal in a first direction.

3. The system of claim 2, wherein the first magnetic induction unit further comprises a second single ferromagnetic coil configured to transmit the data signal in a second direction.

4. The system of claim 1, wherein the second magnetic induction unit is configured to transmit the second data signal through a secondary communication technology.

5. The system of claim 4, wherein the secondary communication technology comprises at least one of radiofrequency transmission, infrared transmission, and wired electronic transmission.

6. The system of claim 1, wherein the first magnetic induction unit is positioned underground.

7. The system of claim 1, wherein the second magnetic induction unit is positioned within the non-gaseous substance.

8. The system of claim 1, wherein the non-gaseous substance comprises at least one of soil, rock, water, and biological matter.

9. The system of claim 1, further comprising a digital oscillator for modulation of a magnetic carrier signal.

10. The system of claim 1, wherein the second magnetic induction unit is further configured to demodulate the data signal.

11. The system of claim 1, further comprising a base unit configured to receive and process data from the first and second magnetic induction units.

12. A system for underground wireless data transmission by magnetic induction, the system comprising:

a plurality of magnetic induction network nodes each configured to send and receive data signals generated by modulating a magnetic carrier signal, wherein the magnetic induction network nodes are positioned underground, and wherein the magnetic induction network nodes each have an onboard power supply; and

a plurality of soil moisture sensors positioned underground and operatively connected to the plurality of magnetic induction network nodes, wherein at least a subset of the plurality of magnetic induction network nodes are each configured to receive data from at least one of the soil moisture sensors, generate a data signal by modulating a magnetic carrier signal, and transmit the data signal to another magnetic induction network node.

13. The system of claim 12, wherein the magnetic induction network nodes are configured for directional transmission of a data signal.

14. The system of claim 12, further comprising a base unit configured to receive and process data from each of the plurality of magnetic induction network nodes.

15. The system of claim 14, wherein the base unit is further configured to relay the received data to a secondary system.

16. The system of claim 15, wherein the base unit is configured to relay the received data to the secondary system via at least one of a radiofrequency transmission, an infrared transmission, and a wired electronic transmission.

17. The system of claim 12, wherein at least a subset of the magnetic induction network nodes are configured to receive data from an adjacent node, append data to the received data, and transmit the received data and the appended data to another adjacent node.

18. The system of claim 12, further comprising an automated irrigation system operatively connected to the network nodes and configured to distribute water in accordance with data received from the soil moisture sensors.

19. A method for transmitting data signals by magnetic induction, the method comprising:

sensing a variable at a first node;

generating a first modulated magnetic carrier signal with data corresponding to the sensed variable;

transmitting the first modulated magnetic carrier signal to a second node;

sensing a variable at the second node;

generating a second modulated magnetic carrier signal with data corresponding to the variable sensed at the second node;

superimposing data from the variable sensed at the second node on the first modulated magnetic carrier signal by modulation selected from a group consisting of frequency-shift keying (FSK) modulation, phase-shift keying (PSK) modulation, and amplitude modulation (AM); and

transmitting the second modulated magnetic carrier signal to a base node.

20. The method of claim 19, wherein the step of transmitting the first modulated magnetic carrier signal to the second node comprises transmitting the first modulated magnetic carrier signal in a predetermined direction to the second node.

21. The method of claim 19, wherein the second modulated magnetic carrier signal comprises a modulation of the first modulated magnetic carrier signal.

22. The method of claim 19, wherein a digital oscillator is used to generate the first modulated magnetic carrier signal.

23. The method of claim 19, further comprising demodulating the second modulated magnetic carrier signal at the base node.

24. The method of claim 23, wherein the second modulated magnetic carrier signal is demodulated with a microcontroller.

25. The method of claim 24, wherein the step of demodulating the second modulated magnetic carrier signal comprises:

counting the peaks of the second modulated magnetic carrier signal over a predetermined period of time with a digital counter; and

supplying the microcontroller with peak count data for Frequency-Shift Keying (FSK) demodulation.

26. The method of claim 24, wherein the step of demodulating the second modulated magnetic carrier signal comprises:

digitizing the received amplitudes of the second modulated magnetic carrier signal with an analog-to-digital converter; and

supplying the microcontroller with digitized amplitude data for Amplitude Modulation (AM) demodulation.

27. The method of claim 19, wherein the step of transmitting the first modulated magnetic carrier signal to a second node comprises transmitting the first modulated magnetic carrier signal underground to the second node.

28. The method of claim 27, wherein the variable comprises soil moisture content.