Communications system

• US 20040102219A1
• Filed: 12/18/2003
• Published: 05/27/2004
• Est. Priority Date: 11/29/1999
• Status: Active Grant

• Current Assignee: Commonwealth Scientific & Industrial Research Organisation (Commonwealth Of Australia As Represented By Department Of Industry, Innovation, Climate Change, Science, Research And Tertiary Education)
• Original Assignee: Commonwealth Scientific & Industrial Research Organisation (Commonwealth Of Australia As Represented By Department Of Industry, Innovation, Climate Change, Science, Research And Tertiary Education)
• Inventors: Jacka, Colin Eric, Bunton, John David, Daniels, Graham Ross
• Granted Patent: US 7,043,195 B2
• Time in Patent Office: Days
• US Class Current: 455/560
• CPC Class Codes: H04B 5/02 using transceiver
• CPC Class Codes: H04B 5/48 Transceivers
• CPC Class Codes: H04B 7/2606 Arrangements for base station coverage control, e.g. by using relays in tunnels
• CPC Class Codes: H04W 88/085 Access point devices with remote components

Abstract

A communications system, including at least one base station (8) at the surface, at least one repeater station (6) below the surface, and at least one mobile station (4) below the surface, the stations (4, 6, 8) establishing a bidirectional communications path between the mobile station (4) and the base station (8).

Claims

1. A communications system, including:

at least one base station at the surface;

at least one repeater station below the surface; and

at least one mobile station below the surface;

said stations establishing a bidirectional communications path between the mobile station and the base station.

2. A communications system as claimed in claim 1, wherein the communications path from the mobile station to the repeater station is a magnetically coupled wireless communications path.

5. A communications system as claimed in claim 1 or 3, wherein the bidirectional communications path includes a first uplink from the mobile station to the repeater station and a second uplink from the repeater station to the base station.

6. A communications system as claimed in claim 5, wherein the communications path includes a downlink from the base station to the mobile station.

7. A communications system as claimed in claim 5, wherein the communications path include downlinks from the base station to the repeater station and from the repeater station to the mobile station, respectively.

8. A communications system as claimed in claim 1, wherein at least part of the communications path to and from the mobile station is wireless.

9. A communications system as claimed in claim 1 or 3, wherein the downlink to and the uplink from the mobile station is wireless.

10. A communications system as claimed in claim 1 or 3, wherein said communications path is wireless.

11. A communications system as claimed in claim 1 or 3, wherein said communications path has first carrier frequencies between the mobile station and the repeater station and second carrier frequencies between the repeater station and the base station that are substantially different.

12. A communications system as claimed in claim 11, wherein the first carrier frequencies are substantially higher than the second carrier frequencies.

13. A communications system as claimed in claim 1 or 3, wherein the antennas of the stations include conductive loops, and the antennas of the base station and the repeater station have substantially collinear axes, and the antennas of the repeater station and the mobile station are substantially coplanar.

14. A communications system as claimed in claim 13, wherein a carrier frequency between stations is determined by k/(σ

μ

r²) Hz, where;

k varies, depending on the direction of a receive loop relative to a transmit loop of said antennas, from about 2.55 when loop axes are collinear to about 4.75 when loop axes are coplanar;

σ

is the conductivity of the transmission medium;

μ

is the permeability of the transmission medium; and

r is the range of the communications path.

15. A communications system as claimed in claim 14, wherein for communications through earth, a carrier frequency between the mobile station and the repeater station is approximately 10 kHz and a carrier frequency between the repeater station and the base station is approximately 500 Hz.

16. A communications system as claimed in claim 13, wherein the mobile station includes an antenna with a relatively reduced aperture compared to the apertures of the repeater station and the base station antennas.

17. A communications system as claimed in claim 1 or 3 including a plurality of the repeater station arranged in a cellular structure to cover respective communication cells.

18. A communications system as claimed in claim 1 or 3, wherein said stations include link management means for monitoring characteristics of links between the stations, respectively, and for adapting communication parameters of links between the stations on the basis of said characteristics.

19. A communications system as claimed in claim 18, wherein said characteristics include link integrity and quality based on signal strength and signal-to-noise ratio (SNR) data.

20. A communications system as claimed in claim 19, wherein said parameters include frequency, timeslot, modulation type and/or data rate allocation.

21. A communications system as claimed in claim 20, wherein said modulation type includes one of QPSK, QAM and m-FSK.

22. A communications system as claimed in claim 21, wherein said modulation type allows feedback error recovery by including FEC encoding.

23. A communications system as claimed in claim 20, wherein the data rate between said mobile stations and said repeater station is at least one bit/s and the data rate between said repeater station and said base station is greater than 10 bit/s.

24. A communications system as claimed in claim 18, wherein said at least one base station includes a control station for said stations.

25. A communications system as claimed in claim 24, wherein the control station includes a master of said link management means for controlling said adapting of said communication parameters.

26. A communications system as claimed in claim 25, wherein said control station includes message scheduling means for determining traffic bandwidth allocation and generating traffic bandwidth allocation commands for said master link management means.

27. A communications system as claimed in claim 24, wherein said repeater station concentrates and edits traffic on said communications path, under the control of said control station.

28. A communications system as claimed in claim 18, wherein messages for a user of said mobile station are segmented and encoded to provide feedback error recovery.

29. A communications system as claimed in claim 18, wherein said link management means and said communications path are adapted to execute link integrity monitoring.

30. A communications system as claimed in claim 18, wherein said link management means and said communications path are adapted to execute broadcast message delivery with confirmation.

31. A communications system as claimed in claim 18, wherein said link management means and said communications path are adapted to execute directed message delivery in both directions of said path with confirmation.

32. A communications system as claimed in claim 18, wherein said link management means and said communications path are adapted to enable determination of the location of said mobile station.

33. A communications system as claimed in claim 1 or 3, wherein said at least one mobile station has a beacon mode during which said mobile station generates a unique beacon signal detectable in the absence of said communications path.

34. A communications system as claimed in claim 1 or 3, having a downlink mode establishing a unidirectional link from said base station to said mobile station without reliance on said repeater station.

3. A communications system, including:

at least one base station;

at least one repeater station; and

at least one mobile station;

said stations establishing a bidirectional communications path between the mobile station and the base station, and the communications path from the mobile station to the repeater station is a magnetically coupled wireless communications path.

4. A communications system as claimed in claim 3, wherein said at least one base station is at the surface, said at least one repeater station is below the surface, and said at least one mobile station is below the surface.

35. A communications system, including:

a receiver station;

a mobile station; and

conducting means magnetically coupled to said mobile station and said receiver station, said stations establishing a communications path therebetween using said conducting means.

36. A communications system as claimed in claim 35, wherein said conducting means includes a conductive loop.

37. A communications system as claimed in claim 36, wherein said conductive loop comprises a conductor loop with a series of capacitance between said mobile station and said receiver station.

38. A communications system as claimed in claim 36, wherein conductive loop includes a long conductor earthed at both ends.

39. A communications system as claimed in any one of claims 35 to 38, wherein said stations include antennas comprising conductive loops.