Mobile communications system

• US 7,379,673 B2
• Filed: 08/14/2007
• Issued: 05/27/2008
• Est. Priority Date: 06/27/2002
• Status: Expired due to Fees

• Current Assignee: Johns Hopkins University
• Original Assignee: Johns Hopkins University
• Inventors: Frank, Joseph, Krill, Jerry A., Duncan, Donald D., Cipriano, Joseph, Sova, Raymond M., Moore, Craig R.
• Primary Examiner(s): Chan; Jason
• Assistant Examiner(s): WANG, QUAN ZHEN
• Application Number:
  US11/838,504
• Publication Number:
  US 20080044187A1
• Time in Patent Office: 287 Days
• Field of Search: 398/118, 398/125, 398/121
• US Class Current: 398/118
• CPC Class Codes: H04B 10/118 specially adapted for satellite communication
• CPC Class Codes: H04B 7/18508 with satellite system used as relay, i.e. aeronautical mobile satellite service
• CPC Class Codes: H04B 7/18521 Systems of inter linked satellites, i.e. inter satellite service for optical links between satellites H04B10/118

Abstract

A communications system for wireless transceiving of information, comprising an optical array subsystem for transceiving optical signals and a millimeter wave subsystem for transceiving millimeter wave signals, and a beam steering controller for controlling the direction of the optical and millimeter wave signals. The communication system may be on a flying platform, such as a satellite and may communicate with multiple remote terminals.

Claims

1. A system, comprising:

on a flying platform;

a position determiner for the flying platform that issues position signals relating to the position of the flying platform;

a beam steering controller that issues beam steering signals responsive to the position signals;

a millimeter-wave transmit array configured to transmit multiple millimeter-wave signals to free-space in different directions according to the beam steering signals;

a millimeter-wave receive array configured to receive multiple millimeter-wave signals from free-space from different directions according to the beam steering signals;

an optical aperture;

optical array transmit components configured to transmit multiple optical signals through the optical aperture to free-space in different directions according to the beam steering signals;

optical array receive components configured to receive multiple optical signals through the optical aperture from free-space from different directions according to the beam steering signals;

a switch matrix configured to switch signals between the millimeter-wave transmit and receive arrays and the optical array transmit and receive components; and

a controller that configures the switch array to selectively switch the signals between the optical array transmit and receive components and the millimeter-wave transmit and receive arrays.

2. The system of claim 1, wherein the controller configures the switch matrix to selectively switch signals received by either the millimeter-wave receive array or the optical array receive components to either the millimeter-wave transmit array or the optical array transmit components for transmission thereby.

3. The system of claim 1, further comprising, on the flying platform:

an optical cross-link subsystem, coupled to the switch matrix and the beam steering controller, for providing optical communications between the flying platform and another flying platform, wherein the controller configures the switch matrix to selectively switch signals received at any of the millimeter-wave receive array, optical array receive components and the optical cross-link subsystem to any of the millimeter-wave transmit array, the optical array transmit components, or the optical cross-link subsystem for transmission thereby.

4. The system of claim 1, wherein the switch matrix is an optical switch matrix that switches the communication signals between the millimeter-wave transmit and receive arrays and the optical array transmit and receive components in the optical domain.

5. The system of claim 4, further comprising, on the flying platform:

a millimeter-wave-to-optical converter configured to convert millimeter-wave signals received by the millimeter-wave receive array to optical signals to be switched by the optical switch matrix; and

an optical-to-millimeter-wave converter configured to convert millimeter-wave optical signals from the optical switch matrix to millimeter-wave signals to be transmitted by the millimeter-wave transmit array.

6. The system of claim 1, wherein the controller includes

(i) means for determining a quality of the optical signals received by the optical receive array components, and

(ii) means for configuring the switch array to selectively switch signals between the millimeter-wave transmit array, the millimeter-wave receive array, the optical array transmit components and the optical array receive components based on the determined quality.

7. The system of claim 1, wherein the flying platform is one of a LEO satellite, a MEO satellite or a GEO satellite.

8. The system of claim 1, wherein the millimeter-wave receive array comprises:

a plurality of array antenna elements each capable of detecting focused millimeter wavelength energy and converting the focused millimeter wavelength energy into electrical signals; and

a millimeter wavelength lens for focusing incident millimeter energy onto at least one of said array antenna elements;

wherein said plurality of array antenna elements conform to an array focal contour of the millimeter wavelength lens.

9. The system of claim 1, wherein the millimeter wave transmit array comprises:

a millimeter wavelength array transmit antenna, comprising;

a plurality of array antenna elements each capable of converting electrical signals into millimeter wavelength energy and emitting the millimeter wavelength energy; and

a millimeter wavelength lens for focusing the emitted millimeter wavelength energy;

wherein said plurality of array antenna elements conform to an array focal contour of the millimeter wavelength lens.

10. The system of claim 1, further comprising on the flying platform a microwave transceiver for transceiving microwave communication signals to/from free-space.

11. The system of claim 1, wherein the optical array transmit and receive components include a shared optical switch bank in optical communication with the optical aperture, the optical switch bank having optical switches that are switched responsive to the beam steering signals to control

the direction in which the array transmit components transmit the signals through the optical aperture into free-space, and

the direction from which the array receive components receive the signals through the optical aperture from free space.

12. The system of claim 11, wherein the multiple optical switches are connected in a binary branch configuration between a bidirectional optical input and multiple bidirectional optical outputs in optical communication with the optical aperture,

wherein, in a transmit direction, the optical switches switch an optical signal to be transmitted from the input to a selected one of the multiple outputs according to the beam steering signals to control the direction in which the array transmit components transmit the communication signals through the optical aperture into free-space, and

wherein, in a receive direction, the optical switches switch, according to the beam steering signals, a free-space optical signal received through the optical aperture at a selected one of the multiple outputs corresponding to a desired receive direction to the input.

13. The system of claim 1, wherein the position determiner includes a global positioning system and a star tracking system.

14. The system of claim 1, wherein each of the optical signals and each of the millimeter wave signals is a communication signal for conveying information.

15. The system of claim 14, further comprising at least two terrestrially-based terminals for communicating with the flying platform via the communication signals, each of the at least two terrestrial terminals comprising an optical transmitter and a millimeter wave transmitter.

16. The system of claim 14, wherein the flying platform is a satellite, the system further comprising:

a terrestrially-based terminal for communicating with the satellite; and

a relay transceiver incorporated into an aircraft and interposed between the satellite and the terrestrially-based terminal for relaying communication signals between the satellite and the terrestrially-based terminal.

17. The system of claim 16, wherein the relay transceiver converts signals from a millimeter band for aircraft to terrestrially-based terminal transmission and to an optical band for aircraft to satellite transmission.

18. The system of claim 1, further comprising two terrestrially-based terminals each configured to transceive at least one of the optical and millimeter wave signals with the flying platform, wherein the beam steering signals are configured to cause the optical array transmit and receive components and the millimeter wave transmit and receive arrays to adjust the different directions of each of the at least one optical and millimeter wave signals so as to maintain alignment thereof with the each of the terminals respectively as the terminals move relative to the flying platform.

19. The system of claim 1, further comprising terminals, remote from the flying platform, for communicating with the flying platform via the optical and millimeter wave signals, wherein:

the millimeter-wave transmit array is configured to transmit the multiple millimeter-wave signals to free-space in different directions aligned with the multiple terminals according to the beam steering signals;

a millimeter-wave receive array configured to receive the multiple millimeter-wave signals from free-space from different directions aligned with the multiple terminals according to the beam steering signals;

the optical array transmit components are configured to transmit the multiple optical signals through the optical aperture to free-space in different directions aligned with the multiple terminals according to the beam steering signals; and

the optical array receive components are configured to receive the multiple optical signals through the optical aperture from free-space from different directions aligned with the multiple terminals according to the beam steering signals.

20. A system on a flying platform, comprising:

a position determiner for the flying platform that issues position signals relating to the position of the flying platform;

a beam steering controller that issues beam steering signals responsive to the position signals;

a millimeter-wave transmit array configured to transmit to free-space multiple millimeter-wave signals in different directions according to the beam steering signals;

a millimeter-wave receive array configured to receive from free-space multiple millimeter-wave signals from different directions according to the beam steering signals;

at least one optical aperture;

optical array transmit components configured to transmit to free-space multiple optical signals through the at least one optical aperture in different directions according to the beam steering signals;

optical array receive components configured to receive from free-space multiple optical signals through the at least one optical aperture from different directions according to the beam steering signals; and

a controller including

(i) means for determining whether a quality of the optical signals received by the optical array receive components is below a predetermined threshold conducive to optical communication, and if the quality is below the predetermined threshold,

(ii) means for causing the millimeter-wave transmit and receive arrays to transceive free-space signals instead of the optical array transmit and receive components.

21. A system on a flying platform, comprising:

a position determiner for the flying platform that issues position signals relating to the position of the flying platform;

a beam steering controller that issues beam steering signals responsive to the position signals;

a millimeter-wave transmit array configured to transmit multiple millimeter-wave signals to free-space in different directions according to the beam steering signals;

a millimeter-wave receive array configured to receive multiple millimeter-wave signals from free-space from different directions according to the beam steering signals;

an optical aperture;

optical array transmit components configured to transmit multiple optical signals through the optical aperture to free-space in different directions according to the beam steering signals;

optical array receive components configured to receive multiple optical signals through the optical aperture from free-space from different directions according to the beam steering signals;

an optical cross-link subsystem, coupled to the switch matrix and the beam steering controller, for providing optical communications between the flying platform and another flying platform;

a switch matrix configured to switch signals between the millimeter-wave transmit and receive arrays, the optical array transmit and receive components, and the optical cross-link subsystem;

a millimeter-wave-to-optical converter configured to convert millimeter-wave signals received by the millimeter-wave receive array to optical signals to be switched by the optical switch matrix;

an optical-to-millimeter-wave converter configured to convert millimeter-wave optical signals from the optical switch matrix to millimeter-wave signals to be transmitted by the millimeter-wave transmit array; and

a controller configured to control the switching of the switch matrix.

22. A mobile terminal for communications, comprising:

a position determiner for the mobile terminal that issues position signals relating to the position of the mobile terminal;

a beam steering controller that issues beam steering signals responsive to the position signals;

an optical aperture;

optical array transmit components configured to transmit multiple optical signals through the optical aperture to free-space in different directions according to the beam steering signals; and

optical array receive components configured to receive multiple optical signals through the optical aperture from free-space from different directions according to the beam steering signals, wherein the optical array transmit and receive components include a shared optical switch bank in optical communication with the optical aperture, the optical switch bank having optical switches that are switched responsive to the beam steering signals to control

(i) the direction in which the optical array transmit components transmit the optical signals through the optical aperture into free-space, and

(ii) the direction from which the optical array receive components receive the optical signals through the optical aperture from free space.

23. The system of claim 22, wherein the optical switches are connected in a binary branch configuration between a bidirectional optical input and multiple bidirectional optical outputs in optical communication with the optical aperture,

wherein, in a transmit direction, the optical switches switch an optical signal to be transmitted from the input to a selected one of the multiple outputs according to the beam steering signals to control the direction in which the optical array transmit components transmit the communication signals through the optical aperture into free-space, and

wherein, in a receive direction, the optical switches switch, according to the beam steering signals, a free-space optical signal received through the optical aperture at a selected one of the multiple outputs corresponding to a desired receive direction to the input.