Satellite for end-to-end beamforming with non-overlapping feeder frequencies

• US 10,075,231 B2
• Filed: 09/26/2017
• Issued: 09/11/2018
• Est. Priority Date: 04/10/2015
• Status: Active Grant

• Current Assignee: ViaSat Incorporated
• Original Assignee: ViaSat Incorporated
• Inventors: Buer, Kenneth V., Miller, Mark J.
• Primary Examiner(s): Chung, Hoon J
• Application Number:
  US15/715,475
• Publication Number:
  US 20180026709A1
• Time in Patent Office: 350 Days
• CPC Class Codes: H01Q 1/06 Means for the lighting or illuminating of antennas, e.g. for purpose of warning
• CPC Class Codes: H01Q 1/247 with frequency mixer, e.g. for direct satellite reception or Doppler radar
• CPC Class Codes: H01Q 1/288 Satellite antennas
• CPC Class Codes: H01Q 19/132 Horn reflector antennas; Off-set feeding
• CPC Class Codes: H01Q 21/0025 Modular arrays
• CPC Class Codes: H01Q 21/24 Combinations of antenna units polarised in different directions for transmitting or receiving circularly and elliptically polarised waves or waves linearly polarised in any direction circularly polarised patch antennas H01Q9/0428; circularly polarised horns H01Q13/0241; cross-polarised horns H01Q13/0258; polarisation converters H01Q15/242; cross-polarised rear feeds H01Q19/136; crossed polarisation dual antenna H01Q25/001
• CPC Class Codes: H01Q 25/001 Crossed polarisation dual antennas orthomode horns H01Q13/0258; cross-polarised rear feeds H01Q19/136; orthomode transducers H01P1/161
• CPC Class Codes: H01Q 3/247 by switching different parts of a primary active element
• CPC Class Codes: H01Q 3/40 with phasing matrix
• CPC Class Codes: H01Q 5/50 Feeding or matching arrangements for broad-band or multi-band operation
• CPC Class Codes: H04B 10/118 specially adapted for satellite communication
• CPC Class Codes: H04B 7/024 Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/18508 with satellite system used as relay, i.e. aeronautical mobile satellite service
• CPC Class Codes: H04B 7/18513 Transmission in a satellite or space-based system
• CPC Class Codes: H04B 7/18515 Transmission equipment in satellites or space-based relays
• CPC Class Codes: H04B 7/18517 Transmission equipment in earth stations
• CPC Class Codes: H04B 7/18534 for enhancing link reliablility, e.g. satellites diversity
• CPC Class Codes: H04B 7/1858 Arrangements for data transmission on the physical system, i.e. for data bit transmission between network components
• CPC Class Codes: H04B 7/18586 : Arrangements for data transporting, e.g. for an end to end data transport or check
• CPC Class Codes: H04B 7/18589 : Arrangements for controlling an end to end session, i.e. for initialising, synchronising or terminating an end to end link
• CPC Class Codes: H04B 7/204 : Multiple access
• CPC Class Codes: H04B 7/2041 : Spot beam multiple access
• CPC Class Codes: H04W 16/26 : Cell enhancers or enhancement, e.g. for tunnels, building shadow
• CPC Class Codes: H04W 16/28 : using beam steering
• CPC Class Codes: H04W 4/00 : Services specially adapted for wireless communication networks; Facilities therefor
• CPC Class Codes: H04W 40/20 : based on geographic position or location
• CPC Class Codes: H04W 76/10 : Connection setup
• CPC Class Codes: H04W 84/06 : Airborne or Satellite Networks space-based or airborne stations H04B7/185

Abstract

Methods and systems are described for providing end-to-end beamforming. For example, end-to-end beamforming systems include end-to-end relays and ground networks to provide communications to user terminals located in user beam coverage areas. The ground segment can include geographically distributed access nodes and a central processing system. Return uplink signals, transmitted from the user terminals, have multipath induced by a plurality of receive/transmit signal paths in the end to end relay and are relayed to the ground network. The ground network, using beamformers, recovers user data streams transmitted by the user terminals from return downlink signals. The ground network, using beamformers generates forward uplink signals from appropriately weighted combinations of user data streams that, after relay by the end-end-end relay, produce forward downlink signals that combine to form user beams.

Claims

1. A satellite for providing communications between a plurality of access nodes and a plurality of user terminals, the plurality of access nodes geographically distributed over an access node coverage area and the plurality of user terminals geographically distributed over a user coverage area, the satellite comprising:

a feeder-link antenna subsystem to illuminate the plurality of access nodes, wherein the feeder-link antenna subsystem comprises a plurality of cooperating feeder-link constituent transmit elements and a plurality of cooperating feeder-link constituent receive elements;

a user-link antenna subsystem to illuminate the user coverage area comprising a plurality of cooperating user-link constituent transmit elements and a plurality of cooperating user-link constituent receive elements;

a first plurality of forward-link transponders, each coupled between one of the feeder-link constituent receive elements and one of the user-link constituent transmit elements, the first plurality of forward-link transponders receiving first forward composite uplink signals over a first frequency range and outputting first forward composite downlink signals over a second frequency range; and

a second plurality of forward-link transponders, each coupled between one of the feeder-link constituent receive elements and one of the user-link constituent transmit elements, the second plurality of forward-link transponders receiving second forward composite uplink signals over a third frequency range and outputting second forward composite downlink signals over the second frequency range,

wherein each of the first forward composite uplink signals is a superposition of a first plurality of forward uplink signals transmitted by the plurality of access nodes over the first frequency range, each of the second forward composite uplink signals is a superposition of a second plurality of forward uplink signals transmitted by the plurality of access nodes over the third frequency range, and the third frequency range is non-overlapping with the first frequency range, wherein the first forward composite downlink signals and the second forward composite downlink signals transmitted by the user link constituent elements superpose to contribute to forming a user beam.

2. The satellite of claim 1, further comprising:

a plurality of forward-link splitters, each of the plurality of forward-link splitters receiving one forward composite uplink signal via one of the feeder-link constituent receive elements and splitting the one forward composite uplink signal into one of the first forward composite uplink signals and one of the second forward composite uplink signals.

3. The satellite of claim 1, wherein inputs of the first plurality of forward-link transponders are coupled with a first set of the plurality of cooperating feeder-link constituent receive elements and inputs of the second plurality of forward-link transponders are coupled with a second set of the plurality of cooperating feeder-link constituent receive elements.

4. The satellite of claim 1, wherein a bandwidth of the second frequency range is greater than a bandwidth of at least one of the first frequency range or the third frequency range.

5. The satellite of claim 1, wherein a bandwidth of the first frequency range is the same as a bandwidth of the third frequency range.

6. The satellite of claim 1, wherein a bandwidth of the first frequency range is different from a bandwidth of the third frequency range.

7. The satellite of claim 1, wherein the first frequency range begins at a first base frequency and the third frequency range begins at a second base frequency that is at least one and a half times the first base frequency.

8. A method for providing communications between a plurality of access nodes and a plurality of user terminals, the plurality of access nodes geographically distributed over an access node coverage area and the plurality of user terminals geographically distributed over a user coverage area, the method comprising:

receiving, at an end-to-end relay, a plurality of first forward composite uplink signals and a plurality of second forward composite uplink signals, wherein each of the plurality of first forward composite uplink signals is a superposition of a first plurality of forward uplink signals transmitted by the plurality of access nodes over a first frequency range and each of the plurality of second forward composite uplink signals is a superposition of a second plurality of forward uplink signals transmitted by the plurality of access nodes over a second frequency range, and wherein the second frequency range is non-overlapping with the first frequency range;

generating a plurality of forward downlink signals, each of the plurality of forward downlink signals generated from one of the plurality of first forward composite uplink signals or the plurality of second forward composite uplink signals; and

transmitting the plurality of forward downlink signals to the plurality of user terminals over a third frequency range.

9. The method of claim 8, wherein the receiving comprises:

receiving, at the end-to-end relay, a plurality of forward composite uplink signals via a plurality of feeder-link constituent receive elements; and

splitting each of the plurality of forward composite uplink signals into one of the plurality of first forward composite uplink signals and one of the plurality of second forward composite uplink signals.

10. The method of claim 8, wherein the receiving comprises:

receiving the plurality of first forward composite uplink signals via a first set of cooperating feeder-link constituent receive elements; and

receiving the plurality of second forward composite uplink signals via a second set of cooperating feeder-link constituent receive elements.

11. The method of claim 8, wherein a bandwidth of the third frequency range is greater than a bandwidth of at least one of the first frequency range or the second frequency range.

12. The method of claim 8, wherein a bandwidth of the first frequency range is the same as a bandwidth of the second frequency range.

13. The method of claim 8, wherein a bandwidth of the first frequency range is different from a bandwidth of the second frequency range.

14. The method of claim 8, wherein the first frequency range begins at a first base frequency and the second frequency range begins at a second base frequency that is at least one and a half times the first base frequency.

15. The method of claim 8, wherein the plurality of forward downlink signals superpose to contribute to forming a user beam.

16. A satellite for providing communications between a plurality of access nodes and a plurality of user terminals, the plurality of access nodes geographically distributed over an access node coverage area and the plurality of user terminals geographically distributed over a user coverage area, the satellite comprising:

a feeder-link antenna subsystem to illuminate the plurality of access nodes, wherein the feeder-link antenna subsystem comprises a plurality of cooperating feeder-link constituent transmit elements and a plurality of cooperating feeder-link constituent receive elements;

a user-link antenna subsystem to illuminate the user coverage area comprising a plurality of cooperating user-link constituent transmit elements and a plurality of cooperating user-link constituent receive elements;

a first plurality of return-link transponders, each coupled between one of the user-link constituent receive elements and one of the feeder-link constituent transmit elements to create a respective one of a plurality of first return composite downlink signals from a respective one of a plurality of first return composite uplink signals, the first plurality of return link transponders receiving the first return composite uplink signals over a first frequency range and outputting the first return composite downlink signals over a second frequency range; and

a second plurality of return-link transponders, each coupled between one of the user-link constituent receive elements and one of the feeder-link constituent transmit elements to create a respective one of a plurality of second return composite downlink signals from a respective one of a plurality of second return composite uplink signals, the first plurality of return link transponders receiving the second return composite uplink signals over the first frequency range and outputting the second return composite downlink signals over a third frequency range, wherein the third frequency range is non-overlapping with the second frequency range,

wherein each of the first plurality of return composite uplink signals and each of the second plurality of return composite uplink signals is a respective superposition of a plurality of return uplink signals transmitted by user terminals of the plurality of user terminals within a plurality of user beam coverage areas of the user coverage area.

17. The satellite of claim 16, further comprising:

a plurality of return-link signal combiners, each of the plurality of return-link signal combiners receiving one of the first return composite downlink signals and one of the second return composite downlink signals and combining the one of the first return composite downlink signals and the one of the second return composite downlink signals to obtain a combined return composite downlink signal for outputting via one of the feeder-link constituent transmit elements.

18. The satellite of claim 16, wherein outputs of the first plurality of return-link transponders are coupled with a first set of the plurality of cooperating feeder-link constituent transmit elements and outputs of the second plurality of return-link transponders are coupled with a second set of the plurality of cooperating feeder-link constituent transmit elements.

19. The satellite of claim 16, wherein a bandwidth of the first frequency range is greater than a bandwidth of at least one of the second frequency range or the third frequency range.

20. The satellite of claim 16, wherein a bandwidth of the second frequency range is the same as a bandwidth of the third frequency range.

21. The satellite of claim 16, wherein a bandwidth of the second frequency range is different from a bandwidth of the third frequency range.

22. The satellite of claim 16, wherein the second frequency range begins at a first base frequency and the third frequency range begins at a second base frequency that is at least one and a half times the first base frequency.

23. A method for providing communications between a plurality of access nodes and a plurality of user terminals, the plurality of access nodes geographically distributed over an access node coverage area and the plurality of user terminals geographically distributed over a user coverage area, the method comprising:

receiving, at a plurality of cooperating user-link constituent receive elements of an end-to-end relay, a plurality of return composite uplink signals over a first frequency range, wherein each of the plurality of return composite uplink signals is a superposition of a plurality of return uplink signals transmitted by user terminals of the plurality of user terminals within a plurality of user beam coverage areas of the user coverage area;

generating a plurality of first return composite downlink signals and a plurality of second return composite downlink signals, wherein each of the first plurality of return composite downlink signals is generated from one of the plurality of return composite uplink signals and each of the plurality of second return composite downlink signals is generated from one of the plurality of return composite uplink signals; and

transmitting the plurality of first return composite downlink signals over a second frequency range and the plurality of second return composite downlink signals over a third frequency range, wherein the third frequency range is non-overlapping with the second frequency range.

24. The method of claim 23, wherein the transmitting comprises:

combining one of the plurality of first return composite downlink signals and one of the plurality of second return composite downlink signals to obtain a combined return composite downlink signal for outputting via one of a plurality of feeder-link constituent transmit elements.

25. The method of claim 23, wherein the transmitting comprises:

transmitting the plurality of first return composite downlink signals via a first set of feeder-link constituent transmit elements; and

transmitting the plurality of second return composite downlink signals via a second set of feeder-link constituent transmit elements.

26. The method of claim 23, wherein a bandwidth of the first frequency range is greater than a bandwidth of at least one of the second frequency range or the third frequency range.

27. The method of claim 23, wherein a bandwidth of the second frequency range is the same as a bandwidth of the third frequency range.

28. The method of claim 23, wherein a bandwidth of the second frequency range is different from a bandwidth of the third frequency range.

29. The method of claim 23, wherein the second frequency range begins at a first base frequency and the third frequency range begins at a second base frequency that is at least one and a half times the first base frequency.