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

Patent metadata

Field	Value
Publication number	US-10075231-B2
Application number	US-201715715475-A
Country	US
Kind code	B2
Filing date	Sep 26, 2017
Priority date	Apr 10, 2015
Publication date	Sep 11, 2018
Grant date	Sep 11, 2018

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.

First claim

What is claimed is:

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

Assignees

• Viasat Inc

Inventors

• Buer Kenneth V
• Miller Mark J

Classifications

• H04W4/00

  Services specially adapted for wireless communication networks; Facilities therefor · CPC title

• H04B7/0413

  MIMO systems · CPC title

• H04B7/024

  Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems · CPC title

• H04B7/204

  Multiple access · CPC title

• H04B10/118

  specially adapted for satellite communication · CPC title