System for end-to-end beamforming with multi-frequency access nodes

• US 10,211,911 B2
• Filed: 08/06/2018
• Issued: 02/19/2019
• 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): Dean, Raymond S
• Application Number:
  US16/055,703
• Publication Number:
  US 20180351636A1
• Time in Patent Office: 197 Days
• Field of Search: None
• 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 system 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, comprising:

means for generating a forward beam weight matrix for end-to-end beamforming from a plurality of access nodes of an access node cluster to multiple forward user beam coverage areas of the user coverage area via the end-to-end relay, the forward beam weight matrix based at least in part on a first forward uplink channel matrix for forward uplink channels between the plurality of access nodes and the end-to-end relay over a first frequency range and a second forward uplink channel matrix for the forward uplink channels over a second frequency range, wherein the second frequency range is non-overlapping with the first frequency range;

means for generating, based on multiple forward beam signals comprising forward user data streams for transmission to a plurality of the user terminals grouped by multiple forward user beam coverage areas, a plurality of access-node specific forward signals for transmission by the plurality of access nodes, each of the access node-specific forward signals comprising a composite of respective forward beam signals weighted by respective forward beamforming weights of the forward beam weight matrix

means for transmitting, by the plurality of access nodes to the end-to-end relay, first forward uplink signals over the first frequency range and second forward uplink signals over the second frequency range, each one of the first forward uplink signals based on a respective first one of the plurality of access node-specific forward signals, and each one of the second forward uplink signals based on a respective second one of the plurality of access node-specific forward signals, wherein the respective first and second forward uplink signals are pre-corrected to compensate for respective path delays and phase shifts introduced between the plurality of access nodes and the end-to-end relay.

2. The system of claim 1, wherein each of the first forward uplink signals transmitted from the plurality of access nodes is carried via at least a subset of a first set of the multiple receive/transmit signal paths of the end-to-end relay and each of the second forward uplink signals transmitted from the plurality of access nodes is carried via at least a subset of a second set of the multiple receive/transmit signal paths of the end-to-end relay.

3. The system of claim 1, wherein at least a subset of the first forward uplink signals and at least a subset of the second forward uplink signals contribute to forming at least one forward user beam associated with at least one of the multiple forward user beam coverage areas.

4. The system of claim 2, wherein the first set of the multiple receive/transmit signal paths are coupled with a first plurality of antenna elements of a user-link antenna subsystem of the end-to-end relay, and the second set of the multiple receive/transmit signal paths are coupled with a second plurality of antenna elements of the user-link antenna subsystem.

5. The system of claim 4, wherein the first plurality of antenna elements is a first subset of antenna elements of an array of cooperating user-link constituent antenna elements, and the second plurality of antenna elements is a second subset of antenna elements of the array of cooperating user-link constituent antenna elements.

6. The system of claim 5, wherein the first plurality of antenna elements and the second plurality of antenna elements are arranged in an interleaved feed pattern within the array of cooperating user-link constituent antenna elements.

7. The system of claim 4, wherein the first plurality of antenna elements is a first array of cooperating user-link constituent antenna elements, and the second plurality of antenna elements is a second array of cooperating user-link constituent antenna elements.

8. The system of claim 4, wherein a number of elements in the first plurality of antenna elements is different from a number of elements in the second plurality of antenna elements.

9. The system of claim 1, wherein a bandwidth of the first frequency range is the same as a bandwidth of the second frequency range.

10. The system of claim 1, wherein a bandwidth of the first frequency range is different from a bandwidth of the second frequency range.

11. The system of claim 1, further comprising:

means for relaying, by the end-to-end relay, the first forward uplink signals and the second forward uplink signals over a third frequency range.

12. The system of claim 11, 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.

13. The system of claim 11, wherein a bandwidth of the third frequency range is less than a combined bandwidth of the first and second frequency ranges.

14. The system of claim 11, wherein a bandwidth of the third frequency range is the same as a bandwidth of at least one of the first frequency range or the second frequency range.

15. A system 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, comprising:

means for receiving, from the end-to-end relay at an access node cluster comprising a plurality of access nodes at a plurality of geographically distributed locations, a first return downlink signal over a first frequency range and a second return downlink signal over a second frequency range, the first return downlink signal comprising a composite of return uplink signals transmitted from a plurality of the user terminals and relayed by at least a subset of a first set of the multiple receive/transmit signal paths of the end-to-end relay to form a first composite return signal and the second return downlink signal comprising a composite of the return uplink signals transmitted from the plurality of the user terminals and relayed by at least a subset of a second set of the multiple receive/transmit signal paths of the end-to-end relay to form a second composite return signal, and wherein the second frequency range is non-overlapping with the first frequency range;

means for generating a return beam weight matrix for end-to-end beamforming of transmissions from multiple return user beam coverage areas to the plurality of geographically distributed locations via the end-to-end relay, the return beam weight matrix based at least in part on a first return downlink channel matrix for return downlink channels between the end-to-end relay and the plurality of geographically distributed locations over the first frequency range and a second return downlink channel matrix for the return downlink channels over the second frequency range;

means for applying, to a vector of the first and second composite return signals, respective beamforming weights of the return beam weight matrix to obtain a respective plurality of weighted composite return signals associated with each of the multiple return user beam coverage areas; and

means for combining, for the each of the multiple return user beam coverage areas, the respective plurality of weighted composite return signals to obtain a return beam signal associated with the each of the multiple return user beam coverage areas, wherein the respective plurality of weighted composite return signals are corrected to compensate for respective path delays and phase shifts between the end-to-end relay and the plurality of access nodes prior to the combining.

16. The system of claim 15, wherein a bandwidth of the first frequency range is the same as a bandwidth of the second frequency range.

17. The system of claim 15, wherein a bandwidth of the first frequency range is different from a bandwidth of the second frequency range.

18. The system of claim 15, 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.

19. The system of claim 15, wherein at least one of the return beam signals for at least one of the return user beam coverage areas is determined based on at least the first return downlink signal and at least the second return downlink signal.

20. The system of claim 15, wherein the first set of the multiple receive/transmit signal paths are coupled with a first plurality of antenna elements of a user-link antenna subsystem of the end-to-end relay, and the second set of the multiple receive/transmit signal paths are coupled with a second plurality of antenna elements of the user-link antenna subsystem.

21. The system of claim 20, wherein the first plurality of antenna elements is a first subset of antenna elements of an array of cooperating user-link constituent antenna elements, and the second plurality of antenna elements is a second subset of antenna elements of the array of cooperating user-link constituent antenna elements.

22. The system of claim 21, wherein the first plurality of antenna elements and the second plurality of antenna elements are arranged in an interleaved feed pattern within the array of cooperating user-link constituent antenna elements.

23. The system of claim 20, wherein the first plurality of antenna elements is a first array of cooperating user-link constituent antenna elements, and the second plurality of antenna elements is a second array of cooperating user-link constituent antenna elements.

24. The system of claim 20, wherein a number of elements in the first plurality of antenna elements is different from a number of elements in the second plurality of antenna elements.