Interference mitigation for a satellite network

• US 10,257,716 B2
• Filed: 05/04/2018
• Issued: 04/09/2019
• Est. Priority Date: 06/07/2016
• Status: Active Grant

• Current Assignee: Iridium Satellite Llc (Iridium Communications, Incorporated)
• Original Assignee: Iridium Seattle LLC
• Inventors: Tatum, Patrick
• Primary Examiner(s): Trinh, Tan H
• Application Number:
  US15/970,981
• Publication Number:
  US 20180255467A1
• Time in Patent Office: 340 Days
• Field of Search: 455 111, 455 121, 455427, 455429, 4554561, 242354, 2441584, 340902, 342352, 342354, 380209
• CPC Class Codes: H04B 15/00 Suppression or limitation of noise or interference by means associated with receiver H04B1/10
• CPC Class Codes: H04B 7/18513 Transmission in a satellite or space-based system
• CPC Class Codes: H04B 7/195 Non-synchronous stations
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 28/08 Load balancing or load distribution transferring a connection for handling the traffic H04W36/22; wireless traffic scheduling H04W72/12
• CPC Class Codes: H04W 84/06 Airborne or Satellite Networks space-based or airborne stations H04B7/185

Abstract

In one implementation, interference generated by a constellation of satellites is mitigated. Each satellite is configured to provide multiple beams that define a coverage footprint. Anticipated positions are determined for satellites. Based on the anticipated positions, a determination is made that, during a defined period of time, portions of a coverage footprint for a first satellite will be covered by coverage footprints for other satellites. Based on this, a beam assignment for the first satellite is defined in which a first subset of beams configured to provide coverage of a first portion of the first coverage footprint are inactive, and a beam assignment for a second satellite is defined in which a second subset of beams are active, where the second subset of beams provide coverage within the first portion of the first coverage footprint.

Claims

1. A method for mitigating out-of-band interference generated by one or more communications satellites within a constellation of low-Earth orbit communications satellites in near-polar orbits, wherein each satellite has a phased array antenna configured to provide multiple beams that collectively define a coverage footprint for the satellite with individual ones of the beams configured to provide coverage of a respective portion of the coverage footprint, the method comprising:

determining that a first coverage footprint for a first satellite within the constellation of satellites covers a region at a latitude that exceeds a predefined latitude;

as a consequence of having determined that the first coverage footprint for the first satellite exceeds the predefined latitude, inactivating a first subset of beams of the first satellite configured to provide coverage of a first portion of the first coverage footprint; and

while the first subset of beams of the first satellite are inactive, operating a second satellite within the constellation of satellites for which a second coverage footprint overlaps with the first coverage footprint with a second subset of beams configured to provide coverage within the first portion of the first coverage footprint as active.

2. The method of claim 1, further comprising:

inactivating a third subset of beams of the first satellite configured to provide coverage of a second portion of the first coverage footprint as a consequence of having determined that the first coverage footprint for the first satellite exceeds the predefined latitude; and

while the third subset of beams of the first satellite are inactive, operating a third satellite within the constellation of satellites for which a third coverage footprint overlaps with the first coverage footprint with a fourth subset of beams configured to provide coverage within the second portion of the first coverage footprint as active.

3. The method of claim 1, further comprising determining that, during a defined time period, the second coverage footprint of the second satellite is associated with a first latitude, wherein:

inactivating the first subset of beams on the first satellite further comprises;

determining that, during the defined time period, the first coverage footprint of the first satellite is associated with a second latitude,

determining that, during the defined time period, the first latitude associated with the second coverage footprint of the second satellite exceeds the second latitude associated with the first coverage footprint of the first satellite, and

inactivating the first subset of beams on the first satellite during the defined time period as a consequence of having determined that, during the defined time period, the first latitude associated with the second coverage footprint of the second satellite exceeds the second latitude associated with the first coverage footprint of the first satellite; and

operating the second satellite with a second subset of beams configured to provide coverage within the first portion of the first coverage footprint as active while the third subset of beams of the first satellite are inactive comprises operating the second satellite with a second subset of beams configured to provide coverage within the first portion of the first coverage footprint as active during the defined time period as a consequence of having determined that, during the defined time period, the first latitude associated with the second coverage footprint of the second satellite exceeds the second latitude associated with the first coverage footprint of the first satellite.

4. The method of claim 1, further comprising while the first subset of beams of the first satellite are inactive, establishing a communications session between a terminal located within the first portion of the first coverage footprint for the first satellite and the second satellite using one or more of beams from the second subset of beams.

5. The method of claim 1, wherein inactivating the first subset of beams of the first satellite comprises turning off one or more amplifiers on the first satellite configured to drive the beams of the first subset of beams.

6. A system for mitigating out-of-band interference generated by one or more communications satellites within a constellation of low-Earth orbit communications satellites in near-polar orbits, wherein each satellite has a phased array antenna configured to provide multiple beams that collectively define a coverage footprint for the satellite with individual ones of the beams configured to provide coverage of a respective portion of the coverage footprint, the system comprising:

one or more processors; and

a memory coupled to the processors comprising instructions executable by the processors, the processors operable when executing the instructions to;

determine that a first coverage footprint for a first satellite within the constellation of satellites covers a region at a latitude that exceeds a predefined latitude;

as a consequence of having determined that the first coverage footprint for the first satellite exceeds the predefined latitude, inactivate a first subset of beams of the first satellite configured to provide coverage of a first portion of the first coverage footprint; and

while the first subset of beams of the first satellite are inactive, operate a second satellite within the constellation of satellites for which a second coverage footprint overlaps with the first coverage footprint with a second subset of beams configured to provide coverage within the first portion of the first coverage footprint as active.

7. The system of claim 6, wherein the processors are further operable when executing the instructions to:

inactivate a third subset of beams of the first satellite configured to provide coverage of a second portion of the first coverage footprint as a consequence of having determined that the first coverage footprint for the first satellite exceeds the predefined latitude; and

while the third subset of beams of the first satellite are inactive, operate a third satellite within the constellation of satellites for which a third coverage footprint overlaps with the first coverage footprint with a fourth subset of beams configured to provide coverage within the second portion of the first coverage footprint as active.

8. The system of claim 6, wherein the processors are further operable when executing the instructions to determine that, during a defined time period, the second coverage footprint of the second satellite is associated with a first latitude, wherein:

inactivating the first subset of beams on the first satellite further comprises;

determining that, during the defined time period, the first coverage footprint of the first satellite is associated with a second latitude,

determining that, during the defined time period, the first latitude associated with the second coverage footprint of the second satellite exceeds the second latitude associated with the first coverage footprint of the first satellite, and

inactivating the first subset of beams on the first satellite during the defined time period as a consequence of having determined that, during the defined time period, the first latitude associated with the second coverage footprint of the second satellite exceeds the second latitude associated with the first coverage footprint of the first satellite; and

operating the second satellite with a second subset of beams configured to provide coverage within the first portion of the first coverage footprint as active while the third subset of beams of the first satellite are inactive comprises operating the second satellite with a second subset of beams configured to provide coverage within the first portion of the first coverage footprint as active during the defined time period as a consequence of having determined that, during the defined time period, the first latitude associated with the second coverage footprint of the second satellite exceeds the second latitude associated with the first coverage footprint of the first satellite.

9. The system of claim 6, wherein the processors are further operable when executing the instructions to, while the first subset of beams of the first satellite are inactive, establish a communications session between a terminal located within the first portion of the first coverage footprint for the first satellite and the second satellite using one or more of beams from the second subset of beams.

10. The system of claim 6, wherein inactivating the first subset of beams of the first satellite comprises turning off one or more amplifiers on the first satellite configured to drive the beams of the first subset of beams.