Multiple spot-beam systems for satellite communications

• US 4,931,802 A
• Filed: 03/11/1988
• Issued: 06/05/1990
• Est. Priority Date: 03/11/1988
• Status: Expired due to Term

• Current Assignee: Vizada Incorporated (Airbus SE)
• Original Assignee: Communications Satellite Corporation (Reorganized ISA SA)
• Inventors: Zaghloul, Amir I., Evans, John V., Assal, Francois T., Mahle, Christoph E., Gupta, Ramesh K.
• Primary Examiner(s): Moskowitz, Nelson
• Assistant Examiner(s): Cain, David
• Application Number:
  US07/167,287
• Time in Patent Office: 816 Days
• Field of Search: 342/373, 342/356, 370/57, 370/75, 370/80, 370/97, 455/12, 333/104
• US Class Current: 342/356
• CPC Class Codes: H04B 7/18515 Transmission equipment in satellites or space-based relays
• CPC Class Codes: H04B 7/2046 SS-TDMA, TDMA satellite switching
• CPC Class Codes: H04Q 11/04 for time-division multiplexing H04Q11/0001 takes precedence
• CPC Class Codes: H04Q 2213/1302 Relay switches
• CPC Class Codes: H04Q 2213/1304 Coordinate switches, crossbar, 4/2 with relays, coupling field
• CPC Class Codes: H04Q 2213/13107 Control equipment for a part of the connection, distributed control, co-processing
• CPC Class Codes: H04Q 2213/13292 Time division multiplexing, TDM
• CPC Class Codes: H04Q 2213/13333 Earth satellites
• CPC Class Codes: H04Q 2213/13396 Signaling in general, in-band signalling

Abstract

On-board satellite switching is performed in three stages, an outer stage of switching on the up-link side for routing the received signals to either demodulators or frequency translators, a first inner stage of switching, preferably a baseband switch and processor, for routing and processing the outputs of the demodulators, a second inner stage of switching, e.g., a microwave switch matrix, for routing the outputs of the frequency translators, and an outer stage on the down-link side for assembling and routing the down-link spot beams. For a multiple hopping-beam system, the outer stages are microwave switch matrices, and for a hybrid scanning-hopping system the outer stages are beam forming matrices. A general purpose modified rearrangeable switch matrix is also disclosed.

Claims

1. A communications relay apparatus of the type including receive means for receiving communications over a plurality of receiving channels transmit means for transmitting communications over a plurality of transmit channels, and means for routing communications received over any of said receiving channels to any of said transmit channels, said relay apparatus comprising:

first receive outer switching means having inputs connected to a first plurality of said receive channels and selectively directing its inputs to any one of at least first and second outputs;

at least a first demodulator connected to said first output of said first receive outer switching means for providing demodulated data from at least one of said first and second receive channels;

at least a first input means connected to said second output of said first receive outer switching means and for providing modulated data from at least one of said first and second channels;

second receive outer switching means having inputs connected to at least third and fourth receive channels and selectively directing its inputs to any one of at least first and second outputs;

at least a second demodulator connected to said first output of said second receive outer switching means for providing demodulated data from at least one of said third and fourth receive channels;

at least a second input means connected to said second output of said second receive outer switching means and for providing modulated data from at least one of said third and fourth channels;

first inner switching means having at least first and second inputs connected to outputs of said first and second demodulators, respectively, said first inner switching means selectively directing demodulated data from its first and second inputs to either of at least first and second outputs of said first inner switching means;

second inner switching means having at least first and second inputs connected to outputs of said first and second input means, respectively said second inner switching means selectively directing modulated data from its first and second inputs to either of at least first and second outputs of said second inner switching means;

a first remodulation means having an input connected to said first output of said first inner switching means;

a first output means connected to said first output of said second inner switching means; and

first transmit outer switching means having at least a first input connected to an output of said first remodulation means and a second input connected to said first output means, said first outer transmit switching means selectively directing modulated data from its first and second inputs to either of at least first and second outputs of said first outer transmit switching means.

2. An apparatus as defined in claim 1, wherein said first and second input means comprise frequency translators.

3. An apparatus as defined in claim 1 wherein said first output means comprises a frequency translator.

4. An apparatus as defined in claim 1 wherein said first output means comprises a direct connection.

5. An apparatus as defined in claim 1, wherein said first and second channels are in a first frequency band and said third and fourth channels are in a second frequency band.

6. An apparatus as defined in claim 1, wherein said apparatus comprises a multiple hopping-beam satellite and said receive and transmit outer switching means comprise microwave switch matrices.

7. An apparatus as defined in claim 6, further comprising first redundant connection means connected between a plurality of up-link antennas and the inputs to each of said receive outer switching means, and second redundant connection means connected between the outputs of each of said transmit outer switching means and a plurality of down-link antennas.

8. An apparatus as defined in claim 6, wherein said first and second receive outer switching means. first and second inner switching means and first transmit outer switching means collectively form a multistage switch matrix.

9. An apparatus as defined in claim 6, wherein said first and second receive outer switching means, first and second inner switching means and first transmit outer switching means collectively form a rearrangeable switch matrix.

10. An apparatus as defined in claim 9, wherein said rearrangeable switch matrix includes a plurality of (4×

4) switch matrices each of which comprises a crossbar switch matrix.

11. An apparatus as defined in claim 10, wherein each of said β

switching elements comprises a double-pole-double-throw (DPDT) switch.

12. An apparatus as defined in claim 6, wherein each of said first and second receive outer switching means and said first transmit outer switching means matrix.

13. An apparatus as defined in claim 12, wherein said rearrangeable switch matrix includes a plurality of (4×

4) switch matrices each of which comprises a crossbar switch matrix.

14. An apparatus as defined in claim 6, wherein said first input means translates the signal from said second output of said first receive outer switching means to a desired down-link frequency.

15. An apparatus as defined in claim 1, further comprising a second transmit outer switching means having first and second inputs and outputs, a second remodulation mean coupling said second output of said first inner switching means to said first input of said second transmit outer switching means and a second output means connecting said second output of said second inner switching means to said second input of said second transmit outer switching means.

16. An apparatus as defined in claim 1 wherein said first inner switching means comprises a baseband switch and processor.

17. An apparatus as defined in claim 16, wherein said second inner switching means comprises a microwave switch matrix.

18. A communications relay apparatus of the type including receive means for receiving communications over a plurality of receiving channels, transmit means for transmitting communications over a plurality of transmit channels, and means for routing communications received over any of said receiving channels to any of said transmit channels, said relay apparatus comprising:

first receive outer routing means having inputs connected to a first plurality of said receive channels and selectively directing its inputs to any one of at least first and second outputs;

at least a first demodulator connected to said first output of said first receive outer routing means for providing demodulated data from at least one of said first and second receive channels;

at least a first input means connected to said second output of said first receive outer routing means and for providing modulated data from at least one of said first and second channels;

second receive outer routing means having inputs connected to at least third and fourth receive channels and selectively directing its inputs to any one of at least first and second outputs;

at least a second demodulator connected to said first output of said second receive outer routing means for providing demodulated data from at least one of said third and fourth receive channels;

at least a second input means connected to said second output of said second receive outer routing means and for providing modulated data from at least one of said third and fourth channels;

first inner switching means having at least first and second inputs connected to outputs of said first and second demodulators, respectively, said first inner switching means selectively directing demodulated data from its first and second inputs to either of at least first and second outputs of said first inner switching means;

second inner switching means having at least first and second inputs connected to outputs of said first and second input means, respectively, said second inner switching means selectively directing modulated data from its first and second inputs to either of at least first and second outputs of said second inner switching means;

a first remodulation means having an input connected to said first output of said first inner switching means;

a first output means connected to said first output of said second inner switching means; and

first transmit outer routing means having at least a first input connected to an output of said first remodulation means and a second input connected to said first output means, said first outer transmit routing means selectively directing modulated data from its first and second inputs to either of at least first and second outputs of said first outer transmit routing means.

19. An apparatus as defined in claim 18, wherein said first and second input means comprise frequency translators.

20. An apparatus as defined in claim 18 wherein said first output means comprises a frequency translator.

21. An apparatus as defined in claim 18, wherein said first output means comprises a direct connection.

22. An apparatus as defined in claim 18, wherein said first and second channels are in a first frequency band and said third and fourth channels are in a second frequency band.

23. An apparatus as defined in claim 18, wherein said first input means translates the signal from said second output of said first receive outer routing means to a desired down-link frequency.

24. An apparatus as defined in claim 18, further comprising a second transmit outer routing means having first and second inputs and outputs, a second remodulation means coupling said second output of said first inner switching means to said first input of said second transmit outer routing means and a second output means connecting said second output of said second inner switching means to said second input of said second transmit outer routing means.

25. An apparatus as defined in claim 18, wherein said first inner switching means comprises a baseband switch and processor.

26. An apparatus as defined in claim 25, wherein said second inner switching means comprises a microwave switch matrix.

27. An apparatus as defined in claim 18, wherein said apparatus comprises a multiple hybrid scanning-hopping-beam satellite and said receive and transmit outer routing means comprise beam forming matrices.

28. An apparatus as defined in claim 27, wherein a total region of coverage by said satellite is divided into a plurality of hopping beam areas and each hopping beam area is covered by a plurality of simultaneously scanning spot beams all generated by a beam forming matrix dedicated to said area.

29. A communications relay apparatus of the type including receive means for receiving communications over a plurality of receiving channels, transmit means for transmitting communications over a plurality of transmit channels, and means for routing communications received over any of said receiving channels to any of said transmit channels, said means for routing comprising:

first means having inputs connected to a first plurality of said receive channels and selectively directing its inputs to any one of at least first and second outputs of said first means;

second means having a plurality of inputs and a plurality of outputs and selectively directing its inputs to any one of at least first and second outputs of said second means;

third means having a plurality of inputs and a plurality of outputs and selectively directing its inputs to any one of at least first and second outputs of said third means;

first coupling means for coupling the outputs of said first means to the inputs of said second means;

second coupling means for coupling the outputs of said second means to the inputs of said third means; and

at least one of said first and second coupling means including means for changing the frequency of a received signal prior to providing it to a respective input.

30. An apparatus as defined in claim 29, further comprising control means for independently controlling each of said first second and third means.

31. An apparatus as defined in claim 29, wherein said at least one of said first and second coupling means comprises a demodulator.

32. An apparatus as defined in claim 29 wherein said at least one of said first and second coupling means comprises a frequency translator.

33. An apparatus as defined in claim 32 wherein said at least one of said first and second coupling means comprises said first coupling means.

34. An apparatus as defined in claim 29, wherein said first coupling means comprises a demodulator and said second coupling means comprises a remodulator.

35. An apparatus as defined in claim 34, wherein said first coupling means further comprises a frequency translator.

36. An apparatus as defined in claim 29, wherein said first and third means comprise microwave switch matrices.

37. An apparatus as defined in claim 36, wherein said second means comprises a baseband switch and processor means.

38. An apparatus as defined in claim 29, wherein said second means comprises a baseband switch and processor means.

39. An apparatus as defined in claim 29, wherein said first and third means comprise beam forming matrices.

40. An apparatus as defined in claim 39, wherein said second means comprises a microwave switch matrix.