Feeder link configurations to support layered modulation for digital signals

• US 8,259,641 B2
• Filed: 08/12/2008
• Issued: 09/04/2012
• Est. Priority Date: 04/27/2001
• Status: Expired due to Term

• Current Assignee: DIRECTV, LLC (AT&T, Inc.)
• Original Assignee: The DIRECTV Group, Inc. (AT&T, Inc.)
• Inventors: Anderson, Paul R., Santoru, Joseph, Chen, Ernest C.
• Primary Examiner(s): Agosta, Steve D
• Application Number:
  US12/190,526
• Publication Number:
  US 20090073917A1
• Time in Patent Office: 1,484 Days
• Field of Search: 370/310.2, 370/316, 370/317, 370/318, 370319-321, 370/328, 455/11.1, 455/12.1, 455/13.1
• US Class Current: 370/316
• CPC Class Codes: H04B 7/18526 Arrangements for data linking, networking or transporting, or for controlling an end to end session data switching networks H04L12/00
• CPC Class Codes: H04L 27/0008 arrangements for allowing a transmitter or receiver to use more than one type of modulation negotiating modulation type for two-way transmission paths H04L5/1453
• CPC Class Codes: H04N 7/20 Adaptations for transmission via a GHz frequency band, e.g. via satellite

Abstract

Systems and methods are disclosed for feeder link configurations to layered modulation. One feeder link system employs feeder link spot beam to antennas in distinct coverage areas to enable frequency reuse. Another system employs narrow beam width feeder link antenna to illuminate individual satellites also enabling frequency reuse. Yet another system uses layered modulation in the feeder link. Another feeder link system employs a higher order synchronous modulation for the satellite feeder link than is used in the layered modulation downlink signals.

Claims

1. A system for uplinking a layered modulation signal, the layered modulation signal comprising an upper layer signal having an upper layer signal constellation of first symbols and a lower layer signal having a lower layer signal constellation of second symbols non-coherently layered over the upper layer signal constellation of first symbols, the system comprising:

a first receiver for receiving a first feeder link signal for a first satellite transponder on a first satellite, the first satellite transponder transmitting the upper layer signal of the layered modulation signal to at least one receiver;

a second receiver for receiving a second feeder link signal for a second satellite transponder on a second satellite, the second satellite transponder transmitting the lower layer signal layered over the upper layer signal of the layered modulation signal to the at least one receiver;

wherein the second feeder link signal reuses a frequency band of the first feeder link signal and the first satellite and the second satellite have an orbital separation sufficient to allow reuse of the frequency band.

2. The system of claim 1, wherein a first frequency bandwidth of the upper layer signal partially overlaps a second frequency bandwidth of the lower layer signal.

3. The system of claim 1, wherein a first frequency bandwidth of the upper layer signal completely overlaps a second frequency bandwidth of the lower layer signal.

4. The system of claim 1, wherein the upper layer signal comprises a legacy signal and the lower layer signal comprises a non-legacy signal.

5. The system of claim 1, wherein the first satellite transponder for the upper layer signal includes a power combiner.

6. The system of claim 1, wherein at least one of the first feeder link signal and the second feeder link signal are power level adjusted to maintain a relative power level between the upper layer signal and the lower layer signal for reception.

7. The system of claim 1, wherein the upper layer signal and the lower layer signal are non-coherent.

8. A method of uplinking a layered modulation signal, comprising:

receiving a first feeder link signal for a first satellite transponder on a first satellite, the first satellite transponder transmitting an upper layer signal to at least one receiver;

receiving a second feeder link signal for a second satellite transponder on a second satellite, the second satellite transponder transmitting a lower layer signal to the at least one receiver;

wherein the second feeder link signal reuses a frequency band of the first feeder link signal and the first satellite and the second satellite have an orbital separation sufficient to allow reuse of the frequency band;

wherein the layered modulation signal comprises the upper layer signal having an upper layer signal constellation of first symbols and the lower layer signal having a lower layer signal constellation of second symbols non-coherently layered over the upper layer signal constellation of first symbols.

9. The method of claim 8, wherein a first frequency bandwidth of the upper layer signal partially overlaps a second frequency bandwidth of the lower layer signal.

10. The method of claim 8, wherein a first frequency bandwidth of the upper layer signal completely overlaps a second frequency bandwidth of the lower layer signal.

11. The method of claim 8, wherein the upper layer signal comprises a legacy signal and the lower layer signal comprises a non-legacy signal.

12. The method of claim 8, wherein the first satellite transponder for the upper layer signal includes a power combiner.

13. The method of claim 8, wherein at least one of the first feeder link signal and the second feeder link signal are power level adjusted to maintain a relative power level between the upper layer signal and the lower layer signal for reception.

14. The method of claim 8, wherein the upper layer signal and the lower layer signal are non-coherent.