SYSTEMS, METHODS AND DEVICES FOR OVERLAID OPERATIONS OF SATELLITE AND TERRESTRIAL WIRELESS COMMUNICATIONS SYSTEMS

• US 20100035604A1
• Filed: 08/05/2009
• Published: 02/11/2010
• Est. Priority Date: 08/06/2008
• Status: Active Grant

• Current Assignee: ATC Technology Corporation (FedEx Corporation)
• Original Assignee: ATC Technology Corporation (FedEx Corporation)
• Inventors: Nguyen, Serge, Dutta, Santanu, Churan, Gary G., Zheng, Dunmin
• Granted Patent: US 8,433,241 B2
• Time in Patent Office: Days
• US Class Current: 455/427
• CPC Class Codes: H04B 7/18513 Transmission in a satellite or space-based system
• CPC Class Codes: H04B 7/18563 Arrangements for interconnecting multiple systems data switching networks H04L12/00
• CPC Class Codes: H04B 7/18591 Arrangements for interconnecting multiple systems data switching networks H04L12/00

Abstract

A communications system includes a space-based network (SBN) including a plurality of spotbeams using a first set of frequencies and an ancillary terrestrial network (ATN) including a plurality of base stations using a second set of radio frequencies. In a coverage zone of a given spot beam wherein the SBN and the ATN use at least one frequency from the first and second sets of frequencies in common, the SBN uses a narrower bandwidth than the ATN on both forward and return links, the ATN employs frequency spreading on at least its return link communications, the SBN employs spatial beam nulling directed toward at least one ancillary terrestrial component (ATC) of the ATN, the SBN employs forward link margin control, the ATN employs return link power control, the SBN employs return link power control and base stations of the ATN provide isolation in the direction of at least one satellite of the SBN. Using such a combination of measures, the ATN and the SBN may support completely or partially overlapping use of the first and second sets of radio frequencies.

Claims

1. A communications system comprising:

a space-based network (SBN) comprising at least one satellite that generates a plurality of spot beams using a first set of frequencies; and

an ancillary terrestrial network (ATN) using a second set of radio frequencies,

wherein, in a coverage zone of a given spot beam wherein the SBN and the ATN use at least one frequency from the first and second sets of frequencies in common the SBN uses a narrower bandwidth than the ATN on both forward and return links, the ATN employs frequency spreading on at least its return link communications, the SBN employs spatial beam nulling directed toward at least one ancillary terrestrial component (ATC) of the ATN, the SBN employs forward link margin control, the ATN employs return link power control, the SBN employs return link power control and base stations of the ATN provide isolation in the direction of at least one satellite of the SBN.

2. The system of claim 1, wherein the SBN employs fixed and/or adaptive return link spatial beam nulling.

3. The system of claim 2, wherein the SBN employs waveform-blind and/or waveform-aware return link spatial beam nulling.

4. The system of claim 3, wherein the SBN employs return link beamforming based on a linear constrained mean variance (LCMV) algorithm.

5. The system of claim 1, wherein base stations of the ATN employ spectral nulling at frequencies from the first set of radio frequencies.

6. The system of claim 1, wherein the SBN employs forward link spatial beam nulling toward at least one ATC of the ATN.

7. The system of claim 1, wherein the forward link margin control employed by the SBN is configured to provide a terminal communicating with the SBN increased link margin to override interference from a proximate ATN base station.

8. The system of claim 7, wherein the forward link margin control employed by the SBN is configured to provide a terminal communicating with the SBN increased link margin to override interference from a proximate ATN base station until the terminal is in a nominal coverage zone of the proximate ATN base station.

9. The system of claim 1, wherein the forward link margin control employed by the SBN comprises adaptive power control and/or adaptive information rate control.

10. The system of claim 1, further comprising a mobility manager configured to support transfer of communications of a terminal between the SBN and the ATN based on proximity to a base station of the ATN.

11. The system of claim 10, wherein the mobility manager supports idle roaming and/or in-call handover.

12. The system of claim 10, wherein the mobility manager is configured to support transfer of terminal communications between the SBN and the ATN using location information from a location information source other than the SBN or the ATN.

13. The system of claim 12, wherein the location information source other than the SBN or the ATN comprises GPS.

14. The system of claim 1, wherein the base stations provide isolation with respect to satellites of the SBN in a range from around 10 dB to around 15 dB.

15. The system of claim 1, wherein the ATN and the SBN are configured to support completely or partially overlapping use of the first and second sets of radio frequencies.

16. A method of operating a communications system comprising an SBN comprising a plurality of spotbeams using a first set of frequencies and an ATN using a second set of radio frequencies, the method comprising:

operating the SBN and the ATN such that, in a given coverage zone of a given spot beam the SBN and the ATN use at least one frequency from the first and second sets of frequencies in common and, in the given coverage zone;

the SBN using a narrower bandwidth than the ATN on both forward and return links;

the ATN employing frequency spreading on at least its return link communications;

the SBN employing spatial beam nulling directed toward at least one ATC of the ATN;

the SBN employing forward link margin control;

the ATN employing return link power control;

the SBN employing return link power control; and

base stations of the ATN providing isolation in the direction of at least one satellite of the SBN.

17. The method of claim 16, wherein the spatial beam nulling comprises fixed and/or adaptive return link spatial beam nulling.

18. The method of claim 17, wherein the adaptive return link spatial beam nulling comprises waveform-blind and/or waveform-aware return link spatial beam nulling.

19. The method of claim 18, wherein the adaptive return link spatial beam nulling comprise return link spatial beamforming based on a linear constrained mean variance (LCMV) algorithm.

20. The method of claim 16, further comprising base stations of the ATN employing spectral nulling at frequencies from the first set of radio frequencies.

21. The method of claim 16, further comprising the SBN employing forward link spatial beam nulling toward at least one ATC of the ATN.

22. The method of claim 16, wherein the forward link margin control employed by the SBN is configured to provide a terminal communicating with the SBN increased link margin to override interference from a proximate ATN base station.

23. The method of claim 22, wherein the forward link margin control employed by the SBN is configured to provide a terminal communicating with the SBN increased link margin to override interference from a proximate ATN base station until the terminal is in a nominal coverage zone of the proximate ATN base station.

24. The method of claim 16, wherein the forward link margin control employed by the SBN comprises adaptive power control and/or adaptive information rate control.

25. The method of claim 16, further comprising managing terminal mobility to support transfer of communications of a terminal between the SBN and the ATN based on proximity to a base station of the ATN.

26. The method of claim 25, wherein managing terminal mobility comprises supporting idle roaming and/or in-call handover.

27. The method of claim 25, wherein managing terminal mobility comprises supporting transfer of terminal communications between the SBN and the ATN using location information from a location information source other than the SBN or the ATN.

28. The method of claim 26, wherein the location information source other than the SBN or the ATN comprises GPS.

29. The method of claim 16, further comprising the base stations of the ATN providing isolation with respect to satellites of the SBN in a range from around 10 dB to around 15 dB.

30. The method of claim 16, comprising the ATN and the SBN supporting completely or partially overlapping use of the first and second sets of radio frequencies.

31. A communication system comprising:

an SBN comprising at least one satellite that generates a plurality of spot beams using a set of frequencies and configured, in a coverage zone of a given spot beam wherein the SBN and an ATN use at least one frequency in common, to use a narrower bandwidth than the ATN on both forward and return links, to employ spatial beam nulling directed toward at least one ancillary terrestrial component (ATC) of the ATN, to employ return link power control and to employ forward link margin control.

32. The system of claim 31, wherein the SBN is configured employ fixed and/or adaptive return link spatial beam nulling.

33. The system of claim 31, wherein the SBN is configured to employ forward link spatial beam nulling toward at least one ATC of the ATN.

34. The system of claim 31, wherein the forward link margin control employed by the SBN is configured to provide a terminal communicating with the SBN increased link margin to override interference from a proximate ATN base station.

35. The system of claim 31, wherein the forward link margin control employed by the SBN comprises adaptive power control and/or adaptive information rate control.

36. The system of claim 31, further comprising a mobility manager configured to support transfer of communications of a terminal between the SBN and the ATN based on proximity to a base station of the ATN.

37. The system of claim 36, wherein the mobility manager supports idle roaming and/or in-call handover.

38. A communications system comprising:

an ATN comprising a plurality of ATCs, each comprising at least one base station, the ATN configured, in a coverage zone of a given spot beam wherein an SBN and the ATN use at least one frequency in common, to use a bandwidth broader than the SBN on both forward and return links, to employ frequency spreading on at least its return link communications, to employ return link power control and to provide isolation of ATN base stations in the direction of at least one satellite of the SBN.

39. The system of claim 38, wherein base stations of the ATN employ spectral nulling at frequencies used by the SBN.

40. The system of claim 38, further comprising a mobility manager configured to support transfer of communications of a terminal between the SBN and the ATN based on proximity to a base station of the ATN.

41. The system of claim 40, wherein the mobility manager supports idle roaming and/or in-call handover.

42. The system of claim 38, wherein the base stations provide isolation with respect to satellites of the SBN in a range from around 10 dB to around 15 dB.