Apparatus and methods for power control in satellite communications systems with satellite-linked terrestrial stations

• US 20060094352A1
• Filed: 11/02/2004
• Published: 05/04/2006
• Est. Priority Date: 11/02/2004
• Status: Active Grant

• Current Assignee: ATC Technology Corporation (FedEx Corporation)
• Original Assignee: ATC Technology Corporation (FedEx Corporation)
• Inventors: Karabinis, Peter D.
• Granted Patent: US 7,639,981 B2
• Time in Patent Office: Days
• US Class Current: 455/13.4
• CPC Class Codes: H04B 7/18513 Transmission in a satellite or space-based system
• CPC Class Codes: H04B 7/18543 for adaptation of transmission parameters, e.g. power control for detecting or preventing errors in the information received H04L1/00
• CPC Class Codes: H04B 7/18563 Arrangements for interconnecting multiple systems data switching networks H04L12/00

Abstract

A signal power control loop is provided for a link between a terrestrial station and a terminal when the terminal and a satellite are linked via the terrestrial station. The signal power control loop may control transmitted signal power of the terminal and/or the terrestrial station. In some embodiments, the signal power control loop controls transmitted signal power of the terminal and/or the terrestrial station independent of signal power control for a link between the terrestrial station and the satellite.

Claims

1. A method of operating a satellite wireless communications system including a satellite configured to communicate with terminals directly and to communicate with terminals indirectly via a terrestrial station, the method comprising:

providing a signal power control loop for a link between the terrestrial station and a terminal when the terminal and the satellite are linked via the terrestrial station.

2. A method according to claim 1 wherein the terrestrial station is configured on a vehicle.

3. A method according to claim 1 wherein the terrestrial station is distributed over a geographic region.

4. A method according to claim 1 wherein the terrestrial station is substantially localized at a specific geographic location.

5. A method according to claim 1 wherein the terrestrial station transmits information to a terminal using a polarization that is substantially orthogonal to the polarization used by an other system.

6. A method according to claim 1 wherein the terrestrial station receives information from a terminal using at least two antenna elements that are substantially orthogonally polarized and/or configured in space diversity.

7. A method according to claim 1 wherein the terrestrial station receives and/or transmits information in a Time Division Duplex (TDD) mode and/or via an antenna pattern responsive to a location of a terminal.

8. A method according to claim 1, further comprising providing a signal power control loop for a direct link between the terminal and the satellite when the terminal is in direct communication with the satellite.

9. A method according to claim 1, wherein the signal power control loop controls transmitted signal power of the terminal and/or the terrestrial station.

10. A method according to claim 9, wherein the signal power control loop controls transmitted signal power of the terminal and/or the terrestrial station independent of signal power control for a link between the terrestrial station and the satellite.

11. A method according to claim 1, wherein providing a signal power control loop for a link between the terrestrial station and a terminal when the terminal and the satellite are linked via the terrestrial station comprises providing a first signal power control loop for a first link between the terrestrial station and the terminal and further comprising providing a second signal power control loop for a combination of the first link and a second link between the terrestrial station and the satellite concurrent with provision of the first signal power control loop.

12. A method according to claim 11, wherein the first control loop is responsive to the second control loop.

13. A method according to claim 1, wherein providing a signal power control loop for a link between the terrestrial station and a terminal comprises:

receiving a signal transmitted by the terminal at the terrestrial station;

generating power control information responsive to the received signal;

communicating the power control information to the terminal from the terrestrial station; and

controlling a transmitted signal power of the terminal responsive to the communicated power control information.

14. A method according to claim 13:

wherein generating power control information responsive to the received signal comprises generating a measure of received signal power;

wherein communicating the power control information to the terminal from the terrestrial station comprises communicating the measure of received signal power; and

wherein controlling a transmitted signal power of the terminal responsive to the communicated power control information comprises controlling the signal power of the terminal using the communicated measure of received signal power as a control feedback signal.

15. A method according to claim 14:

wherein generating power control information responsive to the received signal comprises generating a power command;

wherein communicating the power control information to the terminal from the terrestrial station comprises communicating the power command; and

wherein controlling a transmitted signal power of the terminal responsive to the communicated power control information comprises controlling the signal power of the terminal to conform to the communicated power command.

16. A method according to claim 1, wherein providing a signal power control loop for a link between the terrestrial station and a terminal comprises:

receiving a signal transmitted by the terrestrial station at the terminal;

generating power control information responsive to the received signal;

communicating the power control information to the terrestrial station from the terminal; and

controlling a transmitted signal power of the terrestrial station responsive to the communicated power control information.

17. A method according to claim 16:

wherein generating power control information responsive to the received signal comprises generating a measure of received signal power;

wherein communicating the power control information to the terrestrial station from the terminal comprises communicating the measure of received signal power; and

wherein controlling a transmitted signal power of the terrestrial station responsive to the communicated power control information comprises controlling the signal power of the terrestrial station using the communicated measure of received signal power as a control feedback signal.

18. A method according to claim 16:

wherein generating power control information responsive to the received signal comprises generating a power command;

wherein communicating the power control information to the terrestrial station from the terminal comprises communicating the power command; and

wherein controlling a transmitted signal power of the terrestrial station responsive to the communicated power control information comprises controlling the signal power of the terrestrial station to conform to the communicated power command.

19. A satellite wireless communications system comprising:

a satellite configured to communicate with terminals directly and to communicate with terminals indirectly via a terrestrial station; and

a first signal power control loop that controls a first link between the terrestrial station and the terminal when the terminal and the satellite are linked via the terrestrial station; and

a second signal power control loop that controls a second link between the terminal and the satellite when the terminal is in direct communication with the satellite.

20. A system according to claim 19, wherein the first signal power control loop controls transmitted signal power of the terminal and/or the terrestrial station.

21. A system according to claim 20, wherein the first signal power control loop controls transmitted signal power of the terminal and/or the terrestrial station independent of signal power control for a link between the terrestrial station and the satellite.

22. A system according to claim 19, further comprising a third signal power control loop that controls a combination of the first link and the second link between the terrestrial station and the satellite concurrent with the first signal power control loop.

23. A system according to claim 22, wherein the first control loop is responsive to the third control loop.

24. A satellite wireless communications system comprising:

a satellite and a terrestrial station, the satellite configured to communicate with terminals directly and to communicate with terminals indirectly via the terrestrial station; and

a signal power controller operative to control a signal power control loop for a link between the terrestrial station and a terminal when the terminal and the satellite are linked via the terrestrial station.

25. A system according to claim 24, wherein the signal power controller is operative to control transmitted signal power of the terminal and/or the terrestrial station.

26. A system according to claim 25, wherein the signal power controller is operative to control transmitted signal power of the terminal and/or the terrestrial station independent of signal power control for a link between the terrestrial station and the satellite.

27. A system according to claim 24, wherein the signal power controller comprises a first signal power controller that controls a first power control loop for a first link between the terrestrial station and the terminal and further comprising a second signal power controller that controls a second signal power control loop for a combination of the first link and a second link between the terrestrial station and the satellite concurrent with provision of the first signal power control loop.

28. A system according to claim 27, wherein the first signal power controller is responsive to the second signal power controller.

29. A system according to claim 24, wherein the terrestrial station comprises:

a first demodulation and regeneration unit configured to demodulate a signal received from the satellite and to regenerate the demodulated signal to produce a first regenerated signal;

a first modulator configured to modulate the first regenerated signal;

a first power amplifier configured to amplify the modulated first regenerated signal for transmission to the terminal;

a second demodulation and regeneration unit configured to demodulate a received signal from the terminal and to regenerate the demodulated signal to produce a second regenerated signal;

a second modulator configured to modulate the second regenerated signal;

a second power amplifier configured to amplify the modulated second regenerated signal for transmission to the satellite;

wherein the first demodulation and regeneration unit is operative to extract transmitted power control information from the signal received from the satellite and to control the second power amplifier responsive thereto; and

wherein the second demodulation and regeneration unit is operative to extract transmitted power control information from the signal received from the terminal and to control the first power amplifier responsive thereto.

30. A system according to claim 24, wherein the terrestrial station comprises:

a first demodulation and regeneration unit configured to demodulate a signal received from the satellite and to regenerate the demodulated signal to provide a first regenerated signal;

a first modulator configured to modulate the first regenerated signal;

a first power amplifier configured to amplify the modulated first regenerated signal for transmission to the terminal;

a second demodulation and regeneration unit configured to demodulate a received signal from the terminal and to regenerate the demodulated signal to provide a second regenerated signal;

a second modulator configured to modulate the second regenerated signal;

a second power amplifier configured to amplify the modulated second regenerated signal for transmission to the satellite;

wherein the first demodulation and regeneration unit is operative to determine received signal power for the signal received from the satellite and to provide power control information to the second demodulation and regeneration unit responsive thereto; and

wherein the second demodulation and regeneration unit is operative to determine received signal power for the signal received from the terminal and to provide power control information to the first demodulation and regeneration unit responsive thereto.

31. A system according to claim 24, wherein the signal power controller is positioned at the terrestrial station.

32. A system according to claim 24, wherein the signal power controller is positioned at the terminal.

33. A terrestrial station for a satellite wireless communications system including a satellite configured to communicate with terminals directly and to communicate with terminals indirectly via the terrestrial station, the terrestrial station comprising:

an interface converter operative to translate between air interfaces for a first link between the terrestrial station and a terminal and second link between the terrestrial station and the satellite and to communicate power control information for a power control loop for the first link.

34. A system according to claim 33 wherein the terrestrial station is configured on a vehicle.

35. A system according to claim 33 wherein the terrestrial station is distributed over a geographic region.

36. A system according to claim 33 wherein the terrestrial station is substantially localized at a specific geographic location.

37. A system according to claim 33 wherein the terrestrial station transmits information to a terminal using a polarization that is substantially orthogonal to the polarization used by an other system.

38. A system according to claim 33 wherein the terrestrial station receives information from a terminal using at least two antenna elements that are substantially orthogonally polarized and/or configured in space diversity.

39. A system according to claim 33 wherein the terrestrial station receives and/or transmits information in a Time Division Duplex (TDD) mode and/or via an antenna pattern responsive to a location of a terminal.

40. A station according to claim 33, further comprising a signal power controller operative to control transmitted signal power of the terminal and/or the terrestrial station responsive to the communicated power control information.

41. A station according to claim 40, wherein the signal power controller is operative to control transmitted signal power of the terminal and/or the terrestrial station independent of signal power control for the second link between the terrestrial station and the satellite.

42. A system according to claim 33, wherein the interface converter comprises:

a first demodulation and regeneration unit configured to demodulate a signal received from the satellite and to regenerate the demodulated signal to produce a first regenerated signal;

a first modulator configured to modulate the first regenerated signal;

a first power amplifier configured to amplify the modulated first regenerated signal for transmission to the terminal;

a second demodulation and regeneration unit configured to demodulate a received signal from the terminal and to regenerate the demodulated signal to produce a second regenerated signal;

a second modulator configured to modulate the second regenerated signal;

a second power amplifier configured to amplify the modulated second regenerated signal for transmission to the satellite;

wherein the first demodulation and regeneration unit is operative to extract transmitted power control information from the signal received from the satellite and to control the second power amplifier responsive thereto; and

wherein the second demodulation and regeneration unit is operative to extract transmitted power control information from the signal received from the terminal and to control the first power amplifier responsive thereto.

43. A system according to claim 33, wherein the interface converter comprises:

a first demodulation and regeneration unit configured to demodulate a signal received from the satellite and to regenerate the demodulated signal to produce a first regenerated signal;

a first modulator configured to modulate the first regenerated signal;

a first power amplifier configured to amplify the modulated first regenerated signal for transmission to the terminal;

a second demodulation and regeneration unit configured to demodulate a received signal from the terminal and to regenerate the demodulated signal to produce a second regenerated signal;

a second modulator configured to modulate the second regenerated signal;

a second power amplifier configured to amplify the modulated second regenerated signal for transmission to the satellite;

wherein the first demodulation and regeneration unit is operative to determine received signal power for the signal received from the satellite and to provide power control information to the second demodulation and regeneration unit responsive thereto; and

wherein the second demodulation and regeneration unit is operative to determine received signal power for the signal received from the terminal and to provide power control information to the first demodulation and regeneration unit responsive thereto.