Satellite system with handover for multiple gateways

• US 10,381,748 B2
• Filed: 06/03/2016
• Issued: 08/13/2019
• Est. Priority Date: 03/29/2016
• Status: Active Grant

• Current Assignee: Maxar Space LLC (Galileo Parent, Inc.)
• Original Assignee: Space Systems/Loral Incorporated (Loral Space and Communications Incorporated)
• Inventors: Hreha, William, Wharton, Anne Elizabeth
• Primary Examiner(s): Rego, Dominic E
• Application Number:
  US15/173,097
• Publication Number:
  US 20180006713A1
• Time in Patent Office: 1,166 Days
• CPC Class Codes: H01Q 21/24 Combinations of antenna units polarised in different directions for transmitting or receiving circularly and elliptically polarised waves or waves linearly polarised in any direction circularly polarised patch antennas H01Q9/0428; circularly polarised horns H01Q13/0241; cross-polarised horns H01Q13/0258; polarisation converters H01Q15/242; cross-polarised rear feeds H01Q19/136; crossed polarisation dual antenna H01Q25/001
• CPC Class Codes: H01Q 3/2682 Time delay steered arrays
• CPC Class Codes: H04B 7/043 using best eigenmode, e.g. beam forming or beam steering
• CPC Class Codes: H04B 7/18513 Transmission in a satellite or space-based system
• CPC Class Codes: H04B 7/18515 Transmission equipment in satellites or space-based relays
• CPC Class Codes: H04B 7/18519 Operations control, administration or maintenance
• CPC Class Codes: H04B 7/18521 Systems of inter linked satellites, i.e. inter satellite service for optical links between satellites H04B10/118
• CPC Class Codes: H04B 7/18523 Satellite systems for providing broadcast service to terrestrial stations, i.e. broadcast satellite service arrangements specially adapted for satellite broadcast receiving H04H40/90; picture transmission via satellite H04N1/00103; television transmission via satellite H04N7/20
• CPC Class Codes: H04B 7/18534 for enhancing link reliablility, e.g. satellites diversity
• CPC Class Codes: H04B 7/18541 for handover of resources
• CPC Class Codes: H04B 7/18547 for geolocalisation of a station position fixing by direction or distance determination G01S5/00
• CPC Class Codes: H04B 7/18578 Satellite systems for providing broadband data service to individual earth stations for selecting H04W; provisions for broadband connection, H04Q11/0478
• CPC Class Codes: H04B 7/18584 Arrangements for data networking, i.e. for data packet routing, for congestion control data switching networks H04L12/00
• CPC Class Codes: H04B 7/18595 Arrangements for adapting broadband applications to satellite systems
• CPC Class Codes: H04B 7/19 Earth-synchronous stations
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 56/0015 one node acting as a reference for the others
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/046 the resource being in the space domain, e.g. beams
• CPC Class Codes: H04W 72/21 : in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 72/23 : in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 84/18 : Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

A satellite communication system provides for handovers between satellites and multiple gateways. Terminals communicate with a first gateway via a first satellite as beams of the first satellite traverse the region. A second gateway is in communication with the first satellite and hands over to a second satellite. The first gateway is at a first location. The second gateway is at a second location separated from the first location in the orbital direction. Terminals handover to the second satellite as beams of the second satellite begin to traverse the region, and the terminals start connecting to and communicating with the second gateway via the second satellite. After all of the terminals of the plurality of terminals handover to the second satellite, the first gateway hands over to the second satellite and then the terminals in the region communicate with the first gateway via the second satellite.

Claims

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

a plurality of terminals in a region communicating with a first gateway via a first non-geostationary satellite traveling in an orbital direction along an orbital path as beams of the first non-geostationary satellite traverse the region;

a second gateway in communication with the first non-geostationary satellite handing over to a second non-geostationary satellite traveling in the orbital direction along the orbital path, the first gateway is at a first location, the second gateway is at a second location, the second location is separated from the first location in the orbital direction;

terminals of the plurality of terminals handing over to the second non-geostationary satellite as beams of the second non-geostationary satellite begin to traverse the region;

as the terminals handover to the second non-geostationary satellite, the terminals start connecting to and communicating with the second gateway via the second non-geostationary satellite;

after all of the terminals of the plurality of terminals handover to the second satellite, the first gateway handing over to the second non-geostationary satellite; and

after the first gateway hands over to the second non-geostationary satellite, the plurality of terminals in the region communicating with the first gateway via the second non-geostationary satellite.

2. The method of claim 1, wherein:

the beams of the first non-geostationary satellite and the beams of the second non-geostationary satellite are time domain beam hopping spot beams.

3. The method of claim 1, wherein:

beams of the first non-geostationary satellite and beams of the second non-geostationary satellite overlap.

4. The method of claim 1, wherein:

the orbital direction is west to east; and

the first location is east of the second location.

5. The method of claim 1, wherein:

the orbital path is along the Equator.

6. The method of claim 1, further comprising:

the first gateway and the second gateway communicating with a common processor that is connected to a network.

7. The method of claim 1, wherein:

at least a subset of the plurality of terminals and the first gateway are in a same spot beam of the beams of the first non-geostationary satellite.

8. The method of claim 1, wherein:

the beams of the first non-geostationary satellite and the beams of the second non-geostationary satellite are spot beams that perform time domain beam hopping according to one or more beam hopping plans; and

the method further comprising the first non-geostationary satellite changing beam hopping plans for the beams of the first non-geostationary satellite while the first non-geostationary satellite travels along the orbital path as beams of the first non-geostationary satellite traverse the region.

9. A satellite communication system, comprising:

a first non-geostationary satellite configured to travel in an orbital direction along an orbital path and to be in wireless communication with a plurality of terminals while in a first portion of the orbital path overlying the terminals;

a first gateway configured to be at a first location that allows for wireless communication with the plurality of terminals via the first non-geostationary satellite;

a second gateway configured to be at a second location that allows for wireless communication with the plurality of terminals via the first non-geostationary satellite, the second location is separated from the first location in the orbital direction;

a shared processor connected to the first gateway and to the second gateway, the shared processor being configured to be in communication with a communication network;

the plurality of terminals being configurable to wirelessly communicate with the shared processor via the first non-geostationary satellite, the wireless communicating with the shared processor passing through an assigned one of the first gateway and the second gateway, the shared processor is configured to assign each respective terminal in the plurality of terminals to respectively communicate with the shared processor via one or the other of the first gateway and the second gateway based on a current location of the first non-geostationary satellite in the orbital path.

10. The satellite communication system of claim 9, wherein:

the first non-geostationary satellite is configured to provide a plurality of spot beams using time domain beam hopping among the spot beams in order to provide communication between the terminals and the processor; and

the first non-geostationary satellite is configured to change hopping plans of the spot beams while the terminals communicate with the processor via the spot beams.

11. The satellite communication system of claim 9, further comprising:

a second non-geostationary satellite, the plurality of terminals configurable to communicate with the processor via the second non-geostationary satellite and either of the first gateway and the second gateway, the processor is configured to assign each terminal to communicate with the processor via the first gateway or via the second gateway based on location of the second geostationary satellite.

12. The satellite communication system of claim 11, wherein:

the second non-geostationary satellite is configured to travel in the orbital direction along the orbital path concurrently with the first non-geostationary satellite traveling in the orbital direction along the orbital path.

13. The satellite communication system of claim 12, wherein:

the processor is configured to instruct the terminals to communicate with the first gateway via the first non-geostationary satellite as beams of the first non-geostationary satellite traverse the region;

the second gateway is configured to handover to the second non-geostationary satellite while the terminals to communicate with the first gateway via the first non-geostationary satellite;

the processor is configured to instruct the terminals of the plurality of terminals to start handing over to the second non-geostationary satellite as beams of the second non-geostationary satellite begin to traverse the region;

the processor is configured to instruct the terminals to start connecting to and communicating with the second gateway via the second non-geostationary satellite as the terminals handover to the second non-geostationary satellite;

the first gateway is configured to handover to the second non-geostationary satellite after all of the terminals of the plurality of terminals handover to the second satellite; and

the processor is configured to instruct the plurality of terminals in the region to communicate with the first gateway via the second non-geostationary satellite after the first gateway hands over to the second non-geostationary satellite.

14. The satellite communication system of claim 13, wherein:

the first non-geostationary satellite configured to provide a plurality of spot beams using time domain beam hopping among the spot beams in order to provide communication between the terminals and the processor; and

the first non-geostationary satellite configured to change hopping plans and routing of the spot beams while the terminals communicate with the processor via the spot beams.

15. The satellite communication system of claim 13, wherein:

beams of the first non-geostationary satellite and beams of the second non-geostationary satellite are configured to overlap.

16. The satellite communication system of claim 13, wherein:

the orbital direction is west to east; and

the first location is east of the second location.

17. The satellite communication system of claim 13, wherein:

the orbital path is along the Equator.

18. The satellite communication system of claim 13, wherein:

at least a subset of the plurality of terminals and the first gateway are configured to be in a same spot beam of the beams of the first non-geostationary satellite.