Systems and methods for inter-system sharing of satellite communications frequencies within a common footprint

• US 20050064813A1
• Filed: 09/02/2004
• Published: 03/24/2005
• Est. Priority Date: 09/11/2003
• Status: Active Grant

• Current Assignee: ATC Technology Corporation (FedEx Corporation)
• Original Assignee: ATC Technology Corporation (FedEx Corporation)
• Inventors: Karabinis, Peter D.
• Granted Patent: US 7,113,743 B2
• Time in Patent Office: Days
• US Class Current: 455/13.200
• CPC Class Codes: H04B 7/18513 Transmission in a satellite or space-based system
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Two satellite communications systems can use the same frequency or frequencies in geographically overlapping footprints, without creating undue interference in a given system that is caused by the same frequency signal(s) that is/are used by the other system. In particular, an aggregate Effective Isotropic Radiated Power (EIRP) of the radioterminals and/or ancillary terrestrial components of a second satellite communications system in the common footprint is sufficiently low, and/or the receive antenna gain of a first satellite communications system is sufficiently low compared to the receive antenna gain of the second satellite communications system, so as to increase an aggregate receiver noise that is seen by the first satellite system receivers by an amount that does not substantially change a Quality of Service (QoS) of the first satellite communications system.

Claims

1. A satellite communications frequency sharing-system comprising:

a first satellite communications system that provides satellite communications over a first satellite frequency band in a first footprint via a first satellite; and

a second satellite communications system that provides satellite communications with radioterminals over the first satellite frequency band in a second footprint that is a sub-area of the first footprint, via a second satellite, wherein a receive antenna gain of the second satellite is higher than a receive antenna gain of the first satellite.

2. A satellite communications frequency sharing system according to claim 1 wherein an aggregate effective isotropic radiated power of the radioterminals is sufficiently low so as to increase an aggregate noise that is seen by the first satellite communications system by an amount that does not substantially change a quality of service of the first satellite communications system.

3. A satellite communications frequency sharing system according to claim 1 wherein an aggregate effective isotropic radiated power of the radioterminals and a receive antenna gain of the first satellite are sufficiently low so as to increase an aggregate noise that is seen by the first satellite communications system by an amount that does not substantially change a quality of service of the first satellite communications system.

4. A satellite communications frequency sharing system according to claim 1 wherein an aggregate effective isotropic radiated power of the radioterminals and a receive antenna gain of the first satellite are sufficiently low so as to increase an aggregate noise that is seen by the first satellite communications system by less than about 3.5%.

5. A satellite communications frequency sharing system according to claim 1 wherein the second satellite communications system also provides terrestrial communications between the radioterminals and at least one ancillary terrestrial component over the first satellite frequency band in the second footprint.

6. A satellite communications frequency sharing system according to claim 5 wherein an aggregate effective isotropic radiated power of the radioterminals and/or the at least one ancillary terrestrial component is sufficiently low so as to increase an aggregate noise that is seen by the first satellite communications system by an amount that does not substantially change a quality of service of the first satellite communications system.

7. A satellite communications frequency sharing system according to claim 5 wherein an aggregate effective isotropic radiated power of the radioterminals and/or the at least one ancillary terrestrial component is sufficiently low so as to increase an aggregate noise that is seen by the first satellite communications system by less than about 6.75%.

8. A satellite communications frequency sharing system according to claim 1 wherein the second footprint is spaced apart from waterways.

9. A satellite communications frequency sharing system according to claim 1 wherein the second footprint is spaced apart from waterways by at least twice a width of the second footprint.

10. A satellite communications frequency sharing system according to claim 1 in combination with the radioterminals.

11. A satellite communications frequency sharing system according to claim 5 in combination with the at least one ancillary terrestrial component.

12. A satellite communications frequency sharing system according to claim 1 wherein a receive antenna gain of the second satellite is at least about 20 dB higher than a receive antenna gain of the first satellite.

40. A satellite communications frequency sharing system according to claim 3 wherein at least one radioterminal of the ensemble of radioterminals of the second satellite communications system communicates with the second satellite by radiating substantially linearly polarized electromagnet energy.

41. A satellite communications frequency sharing system according to claim 5 wherein at least one radioterminal of the ensemble of radioterminals communicates with the at least one ancillary terrestrial component by radiating substantially linearly polarized electromagnetic energy.

42. A satellite communications frequency sharing system according to claim 40 wherein a receive antenna of the first satellite is configured to receive substantially circularly polarized electromagnetic energy.

13. A satellite communications frequency sharing system comprising:

a plurality of first radioterminals that communicate with a first satellite communications system over a first satellite frequency band in a footprint at a first aggregate effective isotropic radiated power; and

a plurality of second radioterminals that communicate with a second satellite communications system over the first satellite frequency band in the footprint at a second aggregate effective isotropic radiated power that is less than the first aggregate effective isotropic radiated power.

14. A satellite communications frequency sharing system according to claim 13 wherein the second aggregate effective isotropic radiated power is sufficiently less than the first aggregate effective isotropic radiated power so as to increase an aggregate noise that is seen by the first satellite communications system by an amount that does not substantially change a quality of service of the first satellite communications system.

15. A satellite communications frequency sharing system according to claim 13 wherein the second aggregate effective isotropic radiated power is sufficiently less than the first aggregate effective isotropic radiated power so as to increase an aggregate noise that is seen by the first satellite communications system by less than about 3.5%.

16. A satellite communications frequency sharing system according to claim 13 wherein at least some of the second radioterminals also communicate terrestrially with at least one ancillary terrestrial component over the first satellite frequency band in the footprint.

17. A satellite communications frequency sharing system according to claim 16 wherein the second aggregate effective isotropic radiated power and/or an aggregate effective isotropic radiated power of the at least one ancillary terrestrial component and/or an aggregate effective isotropic radiated power of the at least some of the second radioterminals that also communicate terrestrially with the at least one ancillary terrestrial component is sufficiently less than the first aggregate effective isotropic radiated power so as to increase an aggregate noise that is seen by the first satellite communications system by an amount that does not substantially change a quality of service of the first satellite communications system.

18. A satellite communications frequency sharing system according to claim 16 wherein the second aggregate effective isotropic radiated power and/or an aggregate effective isotropic radiated power of the at least one ancillary terrestrial component and/or an aggregate effective isotropic radiated power of the at least some of the second radioterminals that also communicate terrestrially with the at least one ancillary terrestrial component is sufficiently less than the first aggregate effective isotropic radiated power so as to increase an aggregate noise that is seen by the first satellite radioterminal communications system by less than about 6.75%.

19. A satellite communications frequency sharing system according to claim 13 wherein a footprint of the second satellite communications system in a footprint of the first satellite communications system is spaced apart from waterways.

20. A satellite communications frequency sharing system according to claim 13 wherein a footprint of the second satellite communications system in a footprint of the first satellite communications system is spaced apart from waterways by at least twice a width of a footprint of the second satellite communications system.

21. A satellite communications frequency sharing system according to claim 16 in combination with the at least one ancillary terrestrial component.

43. A satellite communications frequency sharing system according to claim 13 wherein at least one of the plurality of second radioterminals communicates by radiating substantially linearly polarized electromagnetic energy and wherein the first satellite comprises a receive antenna that is configured to receive substantially circularly polarized electromagnetic energy.

44. A satellite communications frequency sharing system according to claim 13 wherein the first satellite comprises an antenna that is configured to radiate substantially right-hand circularly polarized electromagnetic energy and wherein the second satellite comprises an antenna that is configured to radiate substantially left-hand circularly polarized electromagnetic energy.

22. A satellite communications frequency sharing method for a first satellite communications system that provides satellite communications over a first satellite frequency band in a first footprint via a first satellite, the method comprising:

communicating between radioterminals and a second satellite communications system over the first satellite frequency band in a second footprint that is a sub-area of the first footprint via a second satellite, wherein a receive antenna gain of the second satellite is higher than a receive antenna gain of the first satellite.

23. A satellite communications frequency sharing method according to claim 22 wherein an aggregate effective isotropic radiated power of the radioterminals is sufficiently low so as to increase an aggregate noise that is seen by the first satellite communications system by an amount that does not substantially change a quality of service of the first satellite communications system.

24. A satellite communications frequency sharing method according to claim 22 wherein an aggregate effective isotropic radiated power of the radioterminals and a receive antenna gain of the first satellite are sufficiently low so as to increase an aggregate noise that is seen by the first satellite communications system by an amount that does not substantially change a quality of service of the first satellite communications system.

25. A satellite communications frequency sharing method according to claim 22 wherein an aggregate effective isotropic radiated power of the radioterminals and a receive antenna gain of the first satellite are sufficiently low so as to increase an aggregate noise that is seen by the first satellite communications system by less than about 3.5%.

26. A satellite communications frequency sharing method according to claim 22 further comprising:

communicating terrestrially between at least some of the radioterminals and at least one ancillary terrestrial component over the first satellite frequency band in the second footprint.

27. A satellite communications frequency sharing method according to claim 26 wherein an aggregate effective isotropic radiated power of the radioterminals and/or the at least one ancillary terrestrial component is sufficiently low so as to increase an aggregate noise that is seen by the first satellite communications system by an amount that does not substantially change a quality of service of the first satellite communications system.

28. A satellite communications frequency sharing method according to claim 26 wherein an aggregate effective isotropic radiated power of the radioterminals and/or the at least one ancillary terrestrial component is sufficiently low so as to increase an aggregate noise that is seen by the first satellite communications system by less than about 6.75%.

29. A satellite communications frequency sharing method according to claim 22 wherein the second footprint is spaced apart from waterways.

30. A satellite communications frequency sharing method according to claim 22 wherein the second footprint is spaced apart from waterways by at least twice a width of the second footprint.

31. A satellite communications frequency sharing method according to claim 22 wherein a receive antenna gain of the second satellite is at least about 20 dB higher than a receive antenna gain of the first satellite.

45. A satellite communications frequency sharing method according to claim 22 wherein the first satellite comprises an antenna that is configured to radiate substantially right-hand circularly polarized electromagnetic energy and wherein the second satellite comprises an antenna that is configured to radiate substantially left-hand circularly polarized electromagnetic energy.

46. A satellite communications frequency sharing method according to claim 22 wherein at least one of the radioterminals communicates by radiating substantially linearly polarized electromagnetic energy and wherein the first satellite comprises a receive antenna that is configured to receive substantially circularly polarized electromagnetic energy.

32. A satellite communications frequency sharing method for a plurality of first radioterminals that communicate with a first satellite communications system over a first satellite frequency band in a footprint at a first aggregate effective isotropic radiated power, the method comprising:

communicating between a plurality of second radioterminals and a second satellite communications system over the first satellite frequency band in the footprint at a second aggregate effective isotropic radiated power that is less than the first aggregate effective isotropic radiated power.

33. A satellite communications frequency sharing method according to claim 32 wherein the second aggregate effective isotropic radiated power is sufficiently less than the first aggregate effective isotropic radiated power so as to increase an aggregate noise that is seen by the first satellite communications system by an amount that does not substantially change a quality of service of the first satellite communications system.

34. A satellite communications frequency sharing method according to claim 32 wherein the second aggregate effective isotropic radiated power is sufficiently less than the first aggregate effective isotropic radiated power so as to increase an aggregate noise that is seen by the first satellite communications system by less than about 3.5%.

35. A satellite communications frequency sharing method according to claim 32 further comprising:

communicating terrestrially between at least some of the second radioterminals and at least one ancillary terrestrial component over the first satellite frequency band in the footprint.

36. A satellite communications frequency sharing method according to claim 35 wherein the second aggregate effective isotropic radiated power and/or an aggregate effective isotropic radiated power of the at least one ancillary terrestrial component is sufficiently less than the first aggregate effective isotropic radiated power so as to increase an aggregate noise that is seen by the first satellite communications system by an amount that does not substantially change a quality of service of the first satellite communications system.

37. A satellite communications frequency sharing method according to claim 35 wherein the second aggregate effective isotropic radiated power and/or an aggregate effective isotropic radiated power of the at least one ancillary terrestrial component is sufficiently less than the first aggregate effective isotropic radiated power so as to increase an aggregate noise that is seen by the first satellite communications system by less than about 6.75%.

38. A satellite communications frequency sharing method according to claim 32 wherein a footprint of the second satellite that is a subset of the footprint is spaced apart from waterways.

39. A satellite communications frequency sharing method according to claim 32 wherein a footprint of the second satellite that is a subset of the footprint is spaced apart from waterways by at least twice a width of a footprint of the second satellite.