Satellite for end-to-end beamforming with access node clusters

• US 10,079,636 B2
• Filed: 09/28/2017
• Issued: 09/18/2018
• Est. Priority Date: 04/10/2015
• Status: Active Grant

• Current Assignee: ViaSat Incorporated
• Original Assignee: ViaSat Incorporated
• Inventors: Buer, Kenneth V., Miller, Mark J., Cronin, Christopher J., Dankberg, Mark D., Runyon, Donald L.
• Primary Examiner(s): Alam, Fayyaz
• Application Number:
  US15/719,186
• Publication Number:
  US 20180019800A1
• Time in Patent Office: 355 Days
• Field of Search: 455 121, 455 131, 455 7, 455427-431
• 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
• CPC Class Codes: H05K 999/99 : dummy group

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 node clusters and a plurality of user terminals, wherein each access node cluster of the plurality of access node clusters comprises a plurality of access nodes geographically distributed within a corresponding access node area, and wherein the plurality of user terminals are geographically distributed over a user coverage area, the satellite comprising:

a feeder-link antenna subsystem comprising a feeder-link element array to illuminate the plurality of access node clusters, the feeder-link element array comprising an array of cooperating feeder-link constituent transmit elements and an array of cooperating feeder-link constituent receive elements;

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

a plurality of forward-link transponders, each coupled between a respective one of the feeder-link constituent receive elements and a respective one of the user-link constituent transmit elements; and

a plurality of return-link transponders, each coupled between a respective one of the user-link constituent receive elements and a respective one of the feeder-link constituent transmit elements.

2. The satellite of claim 1, wherein the feeder-link element array comprises a first set of feeder-link elements illuminating a first one of the plurality of access node clusters and a second set of feeder-link elements illuminating a second one of the plurality of access node clusters.

3. The satellite of claim 2, wherein inputs of a first subset of the plurality of forward-link transponders are coupled with respective feeder-link constituent receive elements of the first set of feeder-link elements and inputs of a second subset of the plurality of forward-link transponders are coupled with respective feeder-link constituent receive elements of the second set of feeder-link elements.

4. The satellite of claim 3, wherein outputs of the first subset of the plurality of forward-link transponders are coupled with user-link constituent transmit elements of a first set of user-link elements and outputs of the second subset of the plurality of forward-link transponders are coupled with user-link constituent transmit elements of a second set of user-link elements.

5. The satellite of claim 3, wherein the first set of feeder-link elements illuminates the first one of the plurality of access node clusters over a first frequency range, and the second set of feeder-link elements illuminates the second one of the plurality of access node clusters over a second frequency range, wherein the second frequency range is non-overlapping with the first frequency range.

6. The satellite of claim 5, wherein:

the first subset of the plurality of forward-link transponders comprise first forward frequency converters that convert first forward input signals over the first frequency range to first output signals at a third frequency range; and

the second subset of the plurality of forward-link transponders comprise second forward frequency converters that convert second input signals over the second frequency range to second output signals over the third frequency range.

7. The satellite of claim 6, wherein inputs of a first subset of the plurality of return-link transponders are coupled with respective user-link constituent receive elements of the first set of user-link elements and inputs of a second subset of the plurality of return-link transponders are coupled with respective user-link constituent receive elements of the second set of user-link elements.

8. The satellite of claim 7, wherein:

the first subset of the plurality of return-link transponders comprise first return frequency converters that convert first return input signals over the third frequency range to first return output signals over the first frequency range; and

the second subset of the plurality of return-link transponders comprise second return frequency converters that convert second return input signals over the third frequency range to second return output signals over the second frequency range.

9. The satellite of claim 2, wherein the plurality of forward-link transponders comprise respective forward-link receive element switches that selectively couple inputs of the plurality of forward-link transponders to respective cooperating feeder-link constituent receive elements of either the first set of feeder-link elements or the second set of feeder-link elements.

10. The satellite of claim 1, wherein:

the user-link element array comprises a first user-link element array illuminating a first portion of the user coverage area and a second user-link element array illuminating a second portion of the user coverage area; and

the plurality of forward-link transponders comprise respective forward-link transmit element switches that selectively couple outputs of the plurality of forward-link transponders to respective cooperating user-link constituent transmit elements of either the first user-link element array or the second user-link element array.

11. The satellite of claim 10, wherein the corresponding access node area of the first one of the plurality of access node clusters is non-overlapping with the second portion of the user coverage area and the corresponding access node area of the second one of the plurality of access node clusters is non-overlapping with the first portion of the user coverage area.

12. The satellite of claim 2, wherein the plurality of return link transponders comprise respective return-link transmit element switches that selectively couple outputs of the plurality of return link transponders to respective cooperating feeder-link constituent transmit elements of either the first feeder-link element array or the second feeder-link element array.

13. The satellite of claim 12, wherein:

the user-link element array comprises a first user-link element array illuminating a first portion of the user coverage area and a second user-link element array illuminating a second portion of the user coverage area; and

the plurality of return-link transponders comprise respective return-link receive element switches that selectively couple inputs of the plurality of return-link transponders to respective cooperating user-link constituent receive elements of either the first user-link element array or the second user-link element array.

14. The satellite of claim 2, wherein:

the feeder-link antenna subsystem comprises a single reflector; and

the first set of feeder-link elements illuminates the first one of the plurality of access node clusters via the single reflector and the second set of feeder-link elements illuminates the second one of the plurality of access node clusters via the single reflector.

15. The satellite of claim 14, wherein the first set of feeder-link elements and the second set of feeder-link elements are disposed within a single feeder-link element array.

16. The satellite of claim 2, wherein the first set of feeder-link elements illuminates the first one of the plurality of access node clusters via a first reflector and the second set of feeder-link elements illuminates the second one of the plurality of access node clusters via a second reflector.

17. A method for providing a communication service to user terminals geographically distributed over a user coverage area via an end-to-end relay comprising multiple receive/transmit signal paths, the method comprising:

receiving, by a plurality of cooperating feeder-link constituent receive elements, composite input forward signals that are superpositions of a plurality of forward uplink signals transmitted by a set of access nodes, the set of access nodes comprising access nodes of at least one of a plurality of access node clusters, wherein each of the plurality of access node clusters comprises a plurality of access nodes at geographically distributed locations within a corresponding one of a plurality of access node areas;

generating a plurality of forward downlink signals from the composite input forward signals via the multiple receive/transmit signal paths; and

transmitting the plurality of forward downlink signals by a plurality of cooperating user-link constituent transmit elements, wherein the forward downlink signals are transmitted to a plurality of the user terminals.

18. The method of claim 17, wherein the plurality of cooperating feeder-link constituent receive elements comprises a first set of cooperating feeder-link constituent receive elements illuminating a first one of the plurality of access node clusters and a second set of cooperating feeder-link constituent receive elements illuminating a second one of the plurality of access node clusters.

19. The method of claim 18, wherein the first set of cooperating feeder-link constituent receive elements receives a first subset of the composite input forward signals over a first frequency range and the second set of cooperating feeder-link constituent receive elements receives a second subset of the composite input forward signals over a second frequency range, and wherein the second frequency range is non-overlapping with the first frequency range.

20. The method of claim 19, wherein the generating the plurality of forward downlink signals comprises frequency converting the first subset of the composite input forward signals from the first frequency range to a third frequency range to obtain a first subset of the plurality of forward downlink signals and frequency converting the second subset of the composite input forward signals from the second frequency range to the third frequency range to obtain a second subset of the plurality of forward downlink signals.

21. The method of claim 18, further comprising:

selectively coupling inputs of a plurality of forward-link transponders to respective cooperating feeder-link constituent receive elements of either the first set of cooperating feeder-link constituent receive elements or the second set of cooperating feeder-link constituent receive elements.

22. The method of claim 21, wherein the plurality of cooperating user-link constituent transmit elements comprises a first set of cooperating user-link constituent transmit elements illuminating a first portion of the user coverage area and a second set of cooperating user-link constituent transmit elements illuminating a second portion of the user coverage area, the method further comprising:

selectively coupling outputs of the plurality of forward-link transponders to respective cooperating user-link constituent transmit elements of either the first set of cooperating user-link constituent transmit elements or the second set of cooperating user-link constituent transmit element.

23. The method of claim 22, wherein the corresponding access node area of the first one of the plurality of access node clusters is non-overlapping with the second portion of the user coverage area and the corresponding access node area of the second one of the plurality of access node clusters is non-overlapping with the first portion of the user coverage area.

24. A method for providing a communication service to user terminals geographically distributed over a user coverage area via an end-to-end relay comprising multiple receive/transmit signal paths, the method comprising:

receiving return uplink signals by a plurality of cooperating user-link constituent receive elements from at least some of the plurality of user terminals;

generating a plurality of return downlink signals from the received return uplink signals; and

transmitting the plurality of return downlink signals by a plurality of cooperating feeder-link constituent transmit elements to a set of access nodes, the set of access nodes comprising access nodes of at least one of a plurality of access node clusters, wherein each of the plurality of access node clusters comprises a plurality of access nodes at geographically distributed locations within a corresponding one of a plurality of access node areas.

25. The method of claim 24, wherein the plurality of cooperating feeder-link constituent transmit elements comprises a first set of cooperating feeder-link constituent transmit elements illuminating a first one of the plurality of access node clusters and a second set of cooperating feeder-link constituent transmit elements illuminating a second one of the plurality of access node clusters.

26. The method of claim 25, wherein the first set of cooperating feeder-link constituent transmit elements transmits a first subset of the plurality of return downlink signals over a first frequency range and the second set of cooperating feeder-link constituent transmit elements transmits a second subset of the plurality of return downlink signals over a second frequency range, and wherein the second frequency range is non-overlapping with the first frequency range.

27. The method of claim 26, wherein the generating the plurality of return downlink signals comprises frequency converting a first subset of the return uplink signals from a third frequency range to the first frequency range to obtain the first subset of the plurality of return downlink signals and frequency converting a second subset of the return uplink signals from the third frequency range to the second frequency range obtain the second subset of the plurality of return downlink signals.

28. The method of claim 25, further comprising:

selectively coupling outputs of a plurality of return-link transponders to respective cooperating feeder-link constituent transmit elements of either the first set of cooperating feeder-link constituent transmit elements or the second set of cooperating feeder-link constituent transmit elements.

29. The method of claim 28, wherein the plurality of cooperating user-link constituent receive elements comprises a first set of cooperating user-link constituent receive elements illuminating a first portion of the user coverage area and a second set of cooperating user-link constituent receive elements illuminating a second portion of the user coverage area, the method further comprising:

selectively coupling inputs of the plurality of return-link transponders to respective cooperating user-link constituent receive elements of either the first set of cooperating user-link constituent receive elements or the second set of cooperating user-link constituent receive elements.

30. The method of claim 29, wherein the corresponding access node area of the first one of the plurality of access node clusters is non-overlapping with the second portion of the user coverage area and the corresponding access node area of the second one of the plurality of access node clusters is non-overlapping with the first portion of the user coverage area.