Method and apparatus for measuring adjacent satellite interference

• US 20050085186A1
• Filed: 05/08/2002
• Published: 04/21/2005
• Est. Priority Date: 05/08/2001
• Status: Abandoned Application

• Current Assignee: COMSAT Corporation (Reorganized ISA SA)
• Original Assignee: COMSAT Corporation (Reorganized ISA SA)
• Inventors: Sandrin, William
• Application Number:
  US10/476,870
• Publication Number:
  US 20050085186A1
• Time in Patent Office: Days
• US Class Current: 455/12.100
• CPC Class Codes: H04B 17/00 Monitoring; Testing of line transmission systems H04B3/46; arrangements for monitoring or testing transmission systems employing electromagnetic waves other than radio waves H04B10/07
• CPC Class Codes: H04B 17/18 Monitoring during normal operation
• CPC Class Codes: H04B 17/309 Measuring or estimating channel quality parameters
• CPC Class Codes: H04B 17/345 Interference values signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR] H04B17/336
• CPC Class Codes: H04B 7/18513 Transmission in a satellite or space-based system

Abstract

A system for determining at least one of uplink ASI and downlink ASI in a satellite communication system having at least a first satellite and a second satellite, each having uplink and downlink footprints and being in communication with respective earth stations and having a potential interference. The system comprises a first antenna for receiving downlink signals communicated from said first satellite, a second antenna for receiving downlink signals communicated from said second satellite, power spectrum measurement equipment connected to the second antenna for measuring the second satellite power spectrum, and CSM equipment connected to the first antenna and the power spectrum measurement equipment for generating an adjacent satellite carrier plan.

Claims

1. A method of characterizing downlink ASI in a communications satellite system having at least a first satellite and at least a second adjacent satellite, each said satellite being in communication with a respective earth station via downlink beams that provide overlapping downlink beam footprints, said method comprising:

a) capturing the power spectrum of the second adjacent satellite;

b) dividing the downlink beam of the second adjacent satellite into transponder segments;

c) performing spectrum analysis on each said transponder segment;

d) analyzing the measured power spectrum of the second adjacent satellite to convert measured transponder spectra to estimates of carrier frequency plans.

2. The method of characterizing downlink ASI as recited in claim 1, further comprising, determining downlink ASI on a system-wide basis by repeating the process for each downlink beam of the first satellite, and for each of plural adjacent satellites.

3. The method characterizing downlink ASI as recited in of claim 1 further comprising using different measurement locations for each of different downlink beams that cover different geographical regions.

4. The method of characterizing downlink ASI as recited in claim 1 further comprising pointing a CSM antenna towards the adjacent satellite.

5. The method of characterizing downlink ASI as recited in claim 1 further comprising using spectral parameters of power, center frequency and spectral shape, and optionally at least one of modulation type, FEC coding and scrambling patterns.

6. A method of characterizing uplink ASI in a communications satellite system having at least a first satellite and a second adjacent satellite, each said satellite being in communication with respective earth stations via downlink beams that provide downlink beam footprints and uplink beams that have uplink beam footprints, said method comprising:

a) using the downlink spectrum of the interfering satellite; and

b) processing the downlink in accordance with the method of

1) capturing the power spectrum of the second adjacent satellite via spectrum measurement equipment;

2) dividing the downlink beam of the second adjacent satellite into segments;

3) performing spectrum analysis on each said segment; and

4) analyzing the measured power spectrum of the second adjacent satellite to convert measured transponder spectra to estimates of carrier frequency plans.

7. The method of characterizing uplink ASI as claimed in claim 6, further comprising:

if the second adjacent satellite uses the same uplink and downlink frequency bands as the first satellite, then using only the power spectrum measurement of the second adjacent satellite'"'"'s downlink spectrum to represent an uplink ASI.

8. The method of characterizing uplink ASI as claimed in claim 6, further comprising:

if either the uplink or the downlink of the second adjacent satellite operates in frequency bands that are different from the first satellite, determining whether the downlink frequency band is the same, and

if the uplink of the second adjacent satellite shares the same frequency band with the first satellite, but where the downlink of the second adjacent satellite uses a different band, receiving the downlink of the second adjacent satellite and characterizing uplink ASI.

9. The method of characterizing uplink ASI as claimed in claim 6, further comprising repeating the characterization of uplink ASI on a system-wide basis, by repeating the process for each uplink beam of the first satellite, and for each adjacent satellite.

10. A method of characterizing uplink ASI as recited in claim 6 further comprising using the derived information in identifying the source of interference.

11. A system for determining at least one of uplink ASI and downlink ASI in a satellite communication system having at least a first satellite and a second satellite, each having uplink and downlink footprints and being in communication with respective earth stations and having a potential interference, comprising:

a first antenna for receiving downlink signals communicated from said first satellite;

a second antenna for receiving downlink signals communicated from said second satellite;

power spectrum measurement equipment connected to said second antenna for measuring the second satellite power spectrum; and

CSM equipment connected to said first antenna and said power spectrum measurement equipment for generating an adjacent satellite carrier plan.

12. The system as set forth in claim 11 wherein said second antenna is a steerable antenna.

13. The system as set forth in claim 11 further comprising at least one of:

a) means for providing ASI interference identification;

b) means for providing data for inter-system coordination;

c) means for providing verification of intra-system ASI provisions; and

d) means for system transmission planning.

14. The system as set forth in claim 13, wherein said means for system transmission planning comprises:

means for analysis of ASI effects on a per carrier basis; and

means for carrier by carrier power level optimization.

15. The system as set forth in claim 11, further comprising means for determining whether each of the uplink and downlink frequency bands for the first and second satellites are the same and, if the same, using the power spectrum of the downlink to represent uplink ASI.