Dynamic satellite beam assignment

• US 10,784,954 B2
• Filed: 03/01/2018
• Issued: 09/22/2020
• Est. Priority Date: 03/02/2017
• Status: Active Grant

• Current Assignee: ViaSat Incorporated
• Original Assignee: ViaSat Incorporated
• Inventors: Becker, Donald, Petranovich, James, Martin, Remberto
• Primary Examiner(s): Shiue, Dong-Chang
• Application Number:
  US16/489,332
• Publication Number:
  US 20200007227A1
• Time in Patent Office: 936 Days
• CPC Class Codes: H04B 17/309 Measuring or estimating channel quality parameters
• CPC Class Codes: H04B 7/0408 using two or more beams, i.e. beam diversity
• CPC Class Codes: H04B 7/18515 Transmission equipment in satellites or space-based relays
• CPC Class Codes: H04B 7/18541 for handover of resources
• CPC Class Codes: H04B 7/18543 for adaptation of transmission parameters, e.g. power control for detecting or preventing errors in the information received H04L1/00
• CPC Class Codes: H04B 7/19 Earth-synchronous stations
• CPC Class Codes: H04B 7/2041 Spot beam multiple access

Abstract

Embodiments provide techniques for dynamic spot beam assignment in a geostationary satellite communications network. For example, a ground processing node in the geostationary satellite network can monitor spot beam coverage area location and can detect a beam drift trigger indicating present drifting of one or more coverage areas. Ground terminals can be identified as serviced by spot beams associated with the drifting coverage area(s) and as experiencing a signal quality impact from the drifting. The ground terminal node can compute an update to a beam assignment map having a reassignment of the identified user terminals from their presently servicing spot beams to another of the spot beams in a manner that seeks to address at least some of the signal quality impact identified as associated with the drifting. Some embodiments further account for load balancing, and/or other factors, and/or can maintain stateful communications between the reassigned user terminals and the geostationary satellite.

Claims

1. A method for dynamic beam assignment in a geostationary satellite communications network, the method comprising:

receiving link measurement data that indicates signal quality at a plurality of locations within a plurality of coverage areas illuminated by a plurality of spot beams of a geostationary satellite;

detecting a beam drift trigger according to the link measurement data, the beam drift trigger indicating a present drifting of a coverage area of the plurality of coverage areas illuminated by a spot beam of the plurality of spot beams of the geostationary satellite;

identifying a set of ground terminals as experiencing a signal quality degradation from the present drifting; and

computing, in a ground processing node in response to detecting the beam drift trigger, an update to a beam assignment map that at least partially counteracts the signal quality degradation by reassigning each of the set of ground terminals from a respective presently assigned spot beam to a respective reassigned spot beam of the plurality of spot beams.

2. The method of claim 1, wherein the identifying further comprises identifying the set of ground terminals as presently assigned to the spot beam of the plurality of spot beams according to the beam assignment map.

3. The method of claim 1, wherein the identifying further comprises identifying the set of ground terminals according to geolocation data associated with each of the set of ground terminals.

4. The method of claim 1, wherein:

the receiving comprises receiving first link measurement data at a first time and receiving second link measurement data at a second time subsequent to the first time; and

the detecting comprises computing a first location of the coverage area at the first time according to the first link measurement data, computing a second location of the coverage area at the second time according to the second link measurement data, and computing at least a threshold amount of drift between the first location and the second location.

5. The method of claim 1, wherein:

the receiving comprises;

receiving first link measurement data at a first time from a plurality of ground terminals geographically distributed across at least the coverage area; and

receiving second link measurement data from the plurality of ground terminals at a second time subsequent to the first time;

the detecting comprises modeling drift of the coverage area by comparing the second link measurement data with the first link measurement data to determine a magnitude of change in quality of service for at least some of the plurality of ground terminals; and

the identifying comprises identifying the set of ground terminals to comprise the at least some of the plurality of ground terminals for which the determined magnitude of change in quality of service indicates at least a predetermined threshold degradation in quality of service.

6. The method of claim 1, wherein:

the computing comprises, for each of the set of ground terminals, assigning the ground terminal to the respective reassigned spot beam, such that the respective reassigned spot beam is determined to provide a higher spectral efficiency than the respective presently assigned spot beam according to the received link measurement data.

7. The method of claim 1, wherein:

the computing comprises determining a present loading of a set of the spot beams with respect to a beam load balancing schema; and

the computing updates the beam assignment map further in compliance with the beam load balancing schema according to the present loading.

8. The method of claim 1, further comprising:

communicating, via the geostationary satellite, a reassignment message instructing the set of ground terminals to update their communications settings according to the updated beam assignment map.

9. The method of claim 8, wherein communicating the reassignment message comprises multicasting the reassignment message to at least the set of ground terminals, the reassignment message indicating, for each of the set of ground terminals, a respective update to at least one of a carrier frequency, polarization orientation, or beam group identifier being used by the ground terminal to communicate with the geostationary satellite.

10. The method of claim 8, wherein the reassignment message instructs the set of ground terminals to update their communications settings according to the updated beam assignment map while maintaining stateful connectivity with the geostationary satellite.

11. The method of claim 10, wherein each of the set of ground terminals is associated with a network identifier that is beam agnostic, such that maintaining stateful connectivity with the geo stationary satellite comprises maintaining the association of each of the set of ground terminals with its network identifier when its communications settings are updated.

12. The method of claim 1, wherein:

the beam drift trigger indicates the present drifting in association with one of a plurality of reflectors of the geostationary satellite, each of the plurality of reflectors focusing a respective portion of the plurality of spot beams of the geostationary satellite.

13. The method of claim 1, wherein the set of ground terminals includes at least one user terminal.

14. The method of claim 1, wherein the set of ground terminals includes at least one gateway terminal.

15. A system for dynamic beam assignment in a geostationary satellite communications network, the system comprising:

a data store having a beam assignment map stored thereon;

a beam tracking structure having;

a link measurement data input; and

a trigger signal output that comprises a beam drift trigger when the link measurement data input indicates a present drifting of a coverage area illuminated by a spot beam of a plurality of spot beams of a geostationary satellite; and

a terminal assignment structure having;

a trigger signal input coupled with the trigger signal output; and

an assignment signal output that comprises a plurality of beam assignment change messages according to an update to the beam assignment map computed, in response to the trigger signal input, to at least partially counteract signal quality degradation of an identified a set of ground terminals resulting from the present drifting, the beam assignment change messages indicating a beam reassignment of each of the set of ground terminals from a respective presently assigned spot beam to a respective reassigned spot beam of the plurality of spot beams.

16. The system of claim 15, further comprising:

a communications interface structure coupled with the beam tracking structure and the terminal assignment structure, and having a network data input and a network data output communicatively couplable with the geostationary satellite via a ground network,

wherein the network data output comprises the assignment signal output in response to the network data input communicating link measurement data to the link measurement data input.

17. The system of claim 16, wherein the communications interface structure comprises:

a network server that operates to maintain a beam-agnostic network identifier associated with each of the set of ground terminals so as to preserve stateful connectivity between the each of the set of ground terminals and the geostationary satellite when implementing the beam reassignment according to the beam assignment change messages.

18. The system of claim 15, wherein the terminal assignment structure further comprises:

a beam loading monitor comprising a stored beam load balancing schema and maintaining a present loading of a set of the spot beams with respect to the beam load balancing schema,

wherein the beam assignment map is computed further in compliance with the beam load balancing schema according to the present loading.

19. The system of claim 15, wherein:

the trigger signal output comprises the beam drift trigger when a difference between a first location of the coverage area computed according to the link measurement data input at a first time and a second location of the coverage area computed according to the link measurement data input at a second time indicates at least a threshold amount of drift between the first location and the second location.

20. The system of claim 15, further comprising:

a ground terminal data store having stored thereon geolocation data for each of at least the set of ground terminals.

21. The system of claim 15, further comprising:

the geostationary satellite.

22. The system of claim 21, further comprising:

a plurality of satellite access ground terminals in communication with the geostationary satellite; and

a ground processing node structure coupled with the plurality of satellite access ground terminals via a ground network, the ground processing node structure comprising the beam tracking structure and the terminal assignment structure.

23. The system of claim 21, wherein:

the geostationary satellite comprises a plurality of reflectors, each focusing a respective portion of the plurality of spot beams of the geostationary satellite,

wherein the trigger signal output is generated according to independent location tracking of each of the plurality of reflectors.

24. The system of claim 15, wherein the set of ground terminals includes at least one user terminal.

25. The system of claim 15, wherein the set of ground terminals includes at least one gateway terminal.

26. A processor for dynamic beam assignment in a geostationary satellite communications network, the processor coupled with a memory having a beam assignment map stored thereon, the processor comprising:

instructions for receiving link measurement data that characterizes signal strength at a plurality of locations over a plurality of spot beams of a geostationary satellite;

instructions for detecting a beam drift trigger according to the link measurement data, the beam drift trigger indicating a present drifting of a coverage area illuminated by at least one spot beam of the plurality of spot beams;

instructions for identifying a set of ground terminals as experiencing a signal quality degradation from the present drifting; and

instructions for computing, in response to detecting the beam drift trigger, an update to the beam assignment map that at least partially counteracts the signal quality degradation by reassigning each of the set of ground terminals from a respective presently assigned spot beam to a respective reassigned spot beam of the plurality of spot beams.

27. A ground processing node of the geostationary satellite communications network having the processor of claim 26 disposed therein.