Feeder link configurations to support layered modulation for digital signals
View Patent ↗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.
1. A system for transmitting signals to a receiver, comprising:
a demodulator for receiving and demodulating a feeder link signal, wherein the feeder link signal comprises a layered modulation feeder link signal including an upper layer feeder link signal and a lower layer feeder link signal, the demodulator comprising a layered modulation demodulator;
a module, for generating an upper layer signal of a layered modulation downlink signal and a lower layer signal of the layered modulation downlink signal from the received feeder link signal;
a first modulator, for modulating the upper layer feeder link signal to produce a modulated upper layer signal of the layered modulation downlink signal for transmission to the receiver; and
a second modulator, for modulating the lower layer feeder link signal to produce a modulated lower layer signal of the layered modulation downlink signal for transmission to the receiver;
wherein the upper layer feeder link signal and the lower layer feeder link signal are transmitted from a common location or each transmitted from a different location.
2. The system of claim 1 , wherein a first frequency bandwidth of the upper layer downlink signal partially overlaps a second frequency bandwidth of the lower layer downlink signal.
3. The system of claim 1 , wherein a first frequency bandwidth of the upper layer downlink signal completely overlaps a second frequency bandwidth of the lower layer downlink signal.
4. The system of claim 1 , wherein the upper layer feeder link signal and the lower layer feeder link signal are coherently transmitted to the layered modulation receiver/demodulator.
5. The system of claim 1 , wherein the upper layer feeder link signal and the lower layer feeder link signal are non-coherently transmitted to the layered modulation receiver/demodulator.
6. The system of claim 1 , wherein the upper layer downlink amplifier includes a power combiner.
7. The system of claim 1 , wherein at least one of the upper layer feeder link signal and the lower layer 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.
8. The system of claim 1 , wherein the modulated upper layer signal is non-coherent with the modulated lower layer signal.
9. A method of transmitting signals to a receiver, comprising:
receiving and demodulating a feeder link signal, wherein the feeder link signal comprises an upper layer feeder link signal and a lower layer feeder link signal;
generating an upper layer signal of a layered modulation downlink signal and a lower layer signal of the layered modulation downlink signal, comprising the steps of:
demodulating the upper layer feeder link signal from the layered modulation feeder link signal;
demodulating the lower layer feeder link signal from the layered modulation feeder link signal; and
modulating the upper layer signal to produce a modulated upper layer signal of the layered modulation downlink signal, comprising the step of modulating the demodulated upper layer feeder link signal; and
modulating the lower layer signal to produce a modulated lower layer signal of the layered modulation downlink signal comprises the step of modulating the demodulated lower layer feeder link signal;
wherein the upper layer feeder link signal and the lower layer feeder link signal are transmitted from a common location or each transmitted from a different location.
10. The method of claim 9 , wherein a first frequency bandwidth of the upper layer downlink signal partially overlaps a second frequency bandwidth of the lower layer downlink signal.
11. The method of claim 9 , wherein a first frequency bandwidth of the upper layer downlink signal completely overlaps a second frequency bandwidth of the lower layer downlink signal.
12. The method of claim 9 , wherein the upper layer feeder link signal and the lower layer feeder link signal are coherently transmitted to the layered modulation receiver/demodulator.
13. The method of claim 9 , wherein the upper layer feeder link signal and the lower layer feeder link signal are non-coherently transmitted to the layered modulation receiver/demodulator.
14. The method of claim 9 , wherein the upper layer downlink amplifier includes a power combiner.
15. The method of claim 9 , wherein at least one of the upper layer feeder link signal and the lower layer 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.
16. The method of claim 9 , wherein the modulated upper layer signal is non-coherent with the modulated lower layer signal.
17. A system for transmitting signals to a receiver, comprising:
a demodulator, for receiving and demodulating a feeder link signal into a first bit stream;
a module, for generating an upper layer signal of a layered modulation downlink signal and a lower layer signal of the layered modulation downlink signal from the received feeder link signal, the module comprising a demultiplexer for demultiplexing the first bit stream into a second bit stream and a third bit stream;
a first modulator, for modulating the upper layer signal to produce a modulated upper layer signal of the layered modulation downlink signal for transmission to the receiver, the first modulator comprising a first lower order modulator for modulating the second bit stream into the upper layer signal of the layered modulation downlink signal; and
a second modulator, for modulating the lower layer signal to produce a modulated lower layer signal of the layered modulation downlink signal for transmission to the receiver, the second modulator comprising a second lower order modulator for modulating the third bit stream into a lower layer signal of the layered modulation signal;
wherein the feeder link signal comprises a modulation of higher order than either the upper layer signal or the lower layer signal, and the modulated upper layer signal is non-coherent with the modulated lower layer signal.
18. The system of claim 17 , wherein a first frequency bandwidth of the upper layer signal partially overlaps a second frequency bandwidth of the lower layer signal.
19. The system of claim 17 , wherein a first frequency bandwidth of the upper layer signal completely overlaps a second frequency bandwidth of the lower layer signal.
20. The system of claim 17 , wherein the higher order synchronous modulation comprises 16QAM and the lower order modulation comprises QPSK.
21. The system of claim 17 , wherein an amplifier system for the upper layer downlink signal includes a power combiner.
22. The system of claim 17 , wherein at least one of the upper layer feeder link signal and the lower layer 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.
23. A method of transmitting signals to a receiver, comprising:
receiving and demodulating a feeder link signal to produce a first bit stream;
demultiplexing the first bit stream into a second bit stream and a third bit stream;
generating an upper layer signal of a layered modulation downlink signal and a lower layer signal of the layered modulation downlink signal from the received feeder link signal;
modulating the upper layer signal to produce a modulated upper layer signal of the layered modulation downlink signal, comprising the step of modulating the second bit stream into the upper layer signal of the layered modulation signal;
modulating the lower layer signal to produce a modulated lower layer signal of the layered modulation downlink signal, comprising the step of modulating the third bit stream into the lower layer signal of the layered modulation signal for transmission to the at least one receiver;
wherein the feeder link signal comprises a modulation of higher order than either the upper layer signal or the lower layer signal, and the modulated upper layer signal is non-coherent with the modulated lower layer signal.
24. The method of claim 23 , wherein a first frequency bandwidth of the upper layer signal partially overlaps a second frequency bandwidth of the lower layer signal.
25. The method of claim 23 , wherein a first frequency bandwidth of the upper layer signal completely overlaps a second frequency bandwidth of the lower layer signal.
26. The method of claim 23 , wherein the higher order synchronous modulation comprises 16QAM and the lower order modulation comprises QPSK.
27. The method of claim 23 , wherein an amplifier system for the upper layer downlink signal includes a power combiner.
28. The method of claim 23 , wherein at least one of the first feeder link signal and the second feeder link signal are power level adjusted to control a relative power level between the upper layer signal and the lower layer signal.