Additional intra-and/or inter-system interference reducing systems and methods for satellite communications systems

• US 20050136836A1
• Filed: 01/14/2005
• Published: 06/23/2005
• Est. Priority Date: 07/30/2003
• Status: Active Grant

• Current Assignee: ATC Technology Corporation (FedEx Corporation)
• Original Assignee: ATC Technology Corporation (FedEx Corporation)
• Inventors: Karabinis, Peter D., Dutta, Santanu, Churan, Gary G., Zheng, Dunmin
• Granted Patent: US 8,670,705 B2
• Time in Patent Office: Days
• US Class Current: 455/12.100
• CPC Class Codes: H04B 7/1851 Systems using a satellite or space-based relay H04B7/18508, H04B7/18521 take precedence; providing specific services H04B7/18523 - H04B7/18576

Abstract

First radio signals are received by a first satellite, the received first radio signals including a desired satellite uplink signal transmitted from a first source using a frequency assigned to the first source and an interfering signal transmitted from a second source using the frequency assigned to the first source. The first radio signals are combined based on a first performance criterion to generate a first output signal. Second radio signals are received by a second satellite, the received second radio signals including a measure of the desired signal. The second radio signals are combined based on a second performance criterion to produce a second output signal. The first and second output signals are combined to generate an estimate of the desired satellite uplink signal.

Claims

1. A method of operating a satellite radiotelephone communications system, the method comprising:

receiving first radio signals by a first satellite, the received first radio signals including a desired signal using a frequency and an interfering signal using the frequency;

combining the first radio signals based on a first performance criterion to generate a first output signal;

receiving second radio signals by a second satellite, the received second radio signals including a measure of the desired signal;

combining the second radio signals based on a second performance criterion to produce a second output signal; and

combining the first and second output signals to generate an estimate of the desired signal.

2. A method according to claim 1:

wherein combining the first radio signals based on a first performance criterion to generate a first output signal comprises;

determining a first timing for the desired signal as received by the first satellite;

determining an error of the first output signal responsive to the determined first timing; and

combining the first radio signals responsive to the determined error of the first output signal; and

wherein combining the second radio signals based on a second performance criterion to generate a second output signal comprises;

determining a second timing for the desired signal as received by the second satellite;

determining an error of the second output signal responsive to the determined second timing; and

combining the second radio signals responsive to the determined error of the second output signal.

3. A method according to claim 2:

wherein determining a first timing for the desired signal as received by the first satellite comprises synchronizing to a timing reference for the desired signal;

wherein determining an error of the first output signal responsive to the determined first timing comprises determining an error for known information in the first output signal responsive to the synchronizing; and

wherein combining the first radio signals responsive to the determined error comprises combining the first radio signals responsive to the error for known information in the first output signal.

4. A method according to claim 1, wherein combining the first radio signals based on a first performance criterion to generate a first output signal comprises:

applying the first radio signals to a plurality of filters;

combining outputs of the plurality of filters to produce the first output signal; and

modifying at least one filter parameter responsive to the first output signal.

5. A method according to claim 1, wherein combining the first and second output signals to generate an estimate of the desired signal comprises maximal ratio combining the first and second output signals.

6. A method according to claim 1, wherein the first satellite serves a first terrestrial coverage area and wherein the second satellite serves a second terrestrial coverage area adjacent and/or overlapping the first coverage area.

7. A method according to claim 6, wherein respective ones of the first and second radio signals correspond to signals of respective satellite spot beams and/or antenna feeds.

8. A satellite radiotelephone communications system, comprising:

a first satellite that receives first radio signals including a desired signal using a frequency and an interfering signal using the frequency;

a second satellite that receives second radio signals including a measure of the desired signal; and

an interference-suppressing signal processor configured to combine the first radio signals based on a first performance criterion to generate a first output signal, to combine the second radio signals based on a second performance criterion to produce a second output signal, and to combine the first and second output signals to generate an estimate of the desired signal.

9. A system according to claim 8:

wherein the interference-suppressing signal processor is configured to determine a first timing for the desired signal as received by the first satellite, to determine an error of the first output signal responsive to the determined first timing, and to combine the first radio signals responsive to the determined error of the first output signal; and

wherein the interference-suppressing signal process is further configured to determine a second timing for the desired signal as received by the second satellite, to determine an error of the second output signal responsive to the determined second timing and to combine the second radio signals responsive to the determined error of the second output signal.

10. A system according to claim 9, wherein the interference-suppressing signal processor is configured to synchronize to a timing reference for the desired signal, to determine an output signal error for known information in the first output signal responsive to the synchronizing, and to combine the first radio signals responsive to the output signal error.

11. A system according to claim 8, wherein the interference-suppressing signal processor comprises:

a plurality of filters configured to receive the first radio signals;

a combiner configured to combine outputs of the plurality of filters to produce the first output signal; and

a controller operative to modify at least one parameter of the plurality of filters responsive to the first output signal signal.

12. A system according to claim 8, wherein the interference-suppressing signal processor comprises a maximal ratio combiner configured to combine the first and second output signals to generate the estimate of the desired signal.

13. A system according to claim 8, wherein the first satellite serves a first terrestrial coverage area and wherein the second satellite serves a second terrestrial coverage area adjacent and/or overlapping the first coverage area.

14. A system according to claim 8, wherein respective ones of the first and second radio signals correspond to signals of respective satellite spot beams and/or antenna feeds.

15. An apparatus, comprising:

an interference-suppressing signal processor configured to combine first radio signals from a first satellite based on a first performance criterion to generate a first output signal, to combine second radio signals from a second satellite based on a second performance criterion to produce a second output signal, and to combine the first and second output signals to generate an estimate of the desired signal.

16. An apparatus according to claim 15:

wherein the interference-suppressing signal processor is configured to determine a first timing for the desired signal as received by the first satellite, to determine an error of the first output signal responsive to the determined first timing, and to combine the first radio signals responsive to the determined error of the first output signal; and

wherein the interference-suppressing signal process is further configured to determine a second timing for the desired signal as received by the second satellite, to determine an error of the second output signal responsive to the determined second timing and to combine the second radio signals responsive to the determined error of the second output signal.

17. An apparatus according to claim 16, wherein the interference-suppressing signal processor is configured to synchronize to a timing reference for the desired signal, to determine an output signal error for known information in the first output signal responsive to the synchronizing, and to combine the first radio signals responsive to the output signal error.

18. An apparatus according to claim 15, wherein the interference-suppressing signal processor comprises:

a plurality of filters configured to receive the first radio signals;

a combiner configured to combine outputs of the plurality of filters to produce the first output signal; and

a controller configured to modify at least one parameter of the plurality of filters responsive to the first output signal.

19. An apparatus according to claim 15, wherein the interference-suppressing signal processor comprises a maximal ratio combiner configured to combine the first and second output signals to generate the estimate of the desired signal.

20. An apparatus according to claim 15, wherein respective ones of the first and second radio signals correspond to signals of respective satellite spot beams and/or antenna feeds.