Feeder link spatial multiplexing in a satellite communication system

• US 6,317,420 B1
• Filed: 06/25/1999
• Issued: 11/13/2001
• Est. Priority Date: 06/25/1999
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Schiff, Leonard N.
• Primary Examiner(s): Jung, Min
• Application Number:
  US09/344,818
• Time in Patent Office: 872 Days
• Field of Search: 370/315, 370/316, 370/319, 370/325, 370/326, 370/480, 370/535
• US Class Current: 370/325
• CPC Class Codes: H04B 7/18539 Arrangements for managing radio, resources, i.e. for establishing or releasing a connection
• CPC Class Codes: H04B 7/2041 Spot beam multiple access

Abstract

A system and method for spatial multiplexing signals on the feeder links of a satellite communication system. A beamforming antenna forms a plurality of feeder beams from signals received from system gateways, each feeder beam illuminating one of the gateways and including a plurality of frequency division multiple access (FDMA) channels. A plurality demultiplexers separate each of the feeder beams into the FDMA channels, and signal combiners combine first and second ones of the channels, each comprising signals corresponding to user terminals illuminated by a specific user beam, to produce a user beam signal which is used by a beamforming user link antenna to form a specific user beam. In a further aspect, a user link beamforming antenna forms a plurality of user beams from signals received from user terminals, each including a plurality of FDMA channels, and a plurality of demultiplexers separate each of the user beams into the channels. A combiner combines a first and a second one of the FDMA channels, which comprise signals corresponding to a gateway illuminated by a specific feeder beam, to produce a feeder beam signal which is used by a user link beamforming antenna to form a specific feeder beam.

Claims

1. An apparatus for use in a satellite communication system including a plurality of gateways, a satellite, and a plurality of user terminals, comprising:

a beamforming feeder link antenna that forms a plurality of feeder beams from signals received from the gateways, each feeder beam illuminating one of the gateways and including a plurality of frequency division multiple access (FDMA) channels;

a plurality of demultiplexers that separate each of said feeder beams into said FDMA channels;

means, including first and second frequency converters to frequency-convert corresponding first and second ones of said plurality of demultiplexed FDMA channels to corresponding first and second frequency-converted FDMA channels, for combining said first frequency-c converted FDMA channel with said second frequency-converted FDMA channel, said first and second frequency-converted FDMA channels comprising signals corresponding to user terminals illuminated by a specific user beam, to produce a user beam signal; and

a beamforming user link antenna that forms said specific user beam using said user beam signal.

2. The apparatus of claim 1, wherein said user beam signal includes a plurality of frequency bands, and wherein said means for combining comprises:

a controller that allocates said first and second FDMA channels to said specific user beam and to first and second ones of the user beam signal frequency bands,

said first frequency converter being adapted to convert said first FDMA channel from the frequency band on which said first FDMA channel was received to said first one of the user beam signal frequency bands, and

said second frequency converter being adapted to convert said second FDMA channel from the frequency band on which said second FDMA channel was received to said second one of the user beam signal frequency bands; and

a multiplexer that multiplexes said frequency-converted first and second FDMA channels to produce said user beam signal.

3. The apparatus of claim 2, wherein said means for combining further comprises:

a switch that routes said frequency-converted first and second FDMA channels to said multiplexer.

4. The apparatus of claim 1, wherein said means for combining includes a plurality of individual frequency converters, each of the individual frequency converters for frequency-converting a respective one of the plurality of demultiplexed FDMA channels.

5. The apparatus of claim 4, wherein said plurality of individual frequency converters are time-shared between the plurality of demultiplexed FDMA channels.

6. A method for use in a satellite communication system including a plurality of gateways, a satellite, and a plurality of user terminals, comprising the steps of:

(a) forming a plurality of feeder beams from signals received from the gateways, each feeder beam illuminating one of the gateways and including a plurality of frequency division multiple access (FDMA) channels;

(b) separating each of said feeder beams into said FDMA channels;

(c) frequency converting first and second ones of said plurality of separated FDMA channels to corresponding first and second frequency-converted FDMA channels;

(d) combining said first frequency-converted FDMA channel with said second frequency-converted FDMA channel, said first and second frequency-converted FDMA channels comprising signals corresponding to user terminals illuminated by a specific user beam, to produce a user beam signal; and

(e) forming said specific user beam using said user beam signal.

7. The method of claim 6, wherein said user beam signal includes a plurality of frequency bands, and wherein step (d) comprises the further steps of:

(f) allocating said first and second FDMA channels to first and second ones of the user beam signal frequency bands; and

(g) multiplexing said frequency-converted first and second FDMA channels to produce said user beam signal.

8. The method of claim 7, wherein step (c) comprises the steps of:

converting said first FDMA channel from the frequency band on which said first FDMA channel was received to said first one of the user beam signal frequency bands; and

converting said second FDMA channel from the frequency band on which said second FDMA channel was received to said second one of the user beam signal frequency bands.

9. An apparatus for use in a satellite communication system including a plurality of gateways, a satellite, and a plurality of user terminals, comprising:

a user link beamforming antenna that forms a plurality of user beams from signals received from the user terminals, each user beam including a plurality of frequency division multiple access (FDMA) channels;

a plurality of demultiplexers that separate each of said user beams into said FDMA channels;

means, including first and second frequency converters to frequency convert corresponding first and second ones of said plurality of demultiplexed FDMA channels to corresponding first and second frequency-converted FDMA channels, for combining said first frequency-converted FDMA channel with said second frequency-converted FDMA channel, said first and second frequency-converted FDMA channels comprising signals corresponding to a gateway illuminated by a specific feeder beam, to produce a feeder beam signal; and

a user link beamforming antenna that forms said specific feeder beam using said feeder beam signal.

10. The apparatus of claim 9, wherein said feeder beam signal includes a plurality of frequency bands, and wherein said means for combining comprises:

a controller that allocates said first and second FDMA channels to said specific feeder beam and to said first and second ones of the feeder beam signal frequency bands,

said first frequency converter being adapted to convert said first FDMA channel from the frequency band on which said first FDMA channel was received to said first one of the feeder beam signal frequency bands, and

said second frequency converter being adapted to convert said second FDMA channel from the frequency band on which said second FDMA channel was received to said second one of the feeder beam signal frequency bands; and

a multiplexer that multiplexes aid frequency-converted first and second FDMA channels to produce said feeder beam signal.

11. The apparatus of claim 10, wherein said means for combining further comprises:

a switch that routes said first FDMA channel to said first frequency converter and that routes said second FDMA channel to said second frequency converter.

12. The apparatus of claim 9, wherein said means for combining includes a plurality of individual frequency converters, each of the individual frequency converters for frequency-converting a respective one of the plurality of demultiplexed FDMA channels.

13. The apparatus of claim 12, wherein said plurality of individual frequency converters are shared between the plurality of demultiplexed FDMA channels.

14. A method for use in a satellite communication system including a plurality of gateways, a satellite, and a plurality of user terminals, comprising the steps of:

(a) forming a plurality of user beams from signals received from the user terminals, each user beam including a plurality of frequency division multiple access (FDMA) channels;

(b) separating each of said user beams into said FDMA channels;

(c) frequency converting first and second ones of said plurality of separated FDMA channels to corresponding first and second frequency-converted FDMA channels;

(d) combining said first frequency-converted FDMA channel with said second frequency-converted FDMA channel, said first and second frequency-converted FDMA channels comprising signals corresponding to a gateway illuminated by a specific feeder beam, to produce a feeder beam signal; and

(e) forming said specific feeder beam using said feeder beam signal.

15. The method of claim 14, wherein said feeder beam signal includes a plurality of frequency bands, and wherein step (d) comprises the further steps of:

(f) allocating said first and second FDMA channels to first and second ones of the feeder beam signal frequency bands; and

(g) multiplexing said frequency-converted first and second FDMA channels to produce said feeder beam signal.

16. The method of claim 15, wherein step (c) comprises the steps of:

converting said first FDMA channel from the frequency band on which said first FDMA channel was received to said first one of the feeder beam signal frequency bands; and

converting said second FDMA channel from the frequency band on which said second FDMA channel was received to said second one of the feeder beam signal frequency bands.