Multi-beam satellite communications system

• US 6,704,543 B1
• Filed: 05/23/2000
• Issued: 03/09/2004
• Est. Priority Date: 09/27/1999
• Status: Expired due to Term

• Current Assignee: EMS Technologies, Inc. (Honeywell International Inc.)
• Original Assignee: EMS Technologies, Inc. (Honeywell International Inc.)
• Inventors: Taylor, Thomas S., Hafner, William R., Sharon, Thomas E., Rigg, Steven H., Howell, James M.
• Primary Examiner(s): Maung, Nay
• Assistant Examiner(s): Orgad, Edan
• Application Number:
  US09/576,475
• Time in Patent Office: 1,386 Days
• Field of Search: 455/12.1, 455/13.1, 455/13.2, 455/13.3, 455/427-436, 455/440, 455/445, 455/456, 455/422, 455/13.4, 455/553, 455/560, 370/357, 370/352, 370/353, 370/354
• US Class Current: 455/12.1
• 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 7/2041 Spot beam multiple access

Abstract

A satellite communications system having ground user terminals, hubs, and a geosynchronous satellite. The satellite generates a network of spot beam coverage areas on the earth. A hub and at least one ground terminal are located in each of at least two spot beams. A first user terminal transmits an uplink signal according to a first signal protocol to the hub through the satellite. A second user terminal receives a downlink signal according to a second signal protocol through the downlink spot beam from the hub through the satellite. The hub may be located in the same spot beam coverage area as the first or the second user terminal or may be located in an altogether different spot beam coverage area. Through selective frequency and/or polarization routing on board the satellite, a hub located within a “parent” beam can communicate with user terminals within the parent beam at a specified frequency and polarization, and can communicate with users in other “dependent” beams on a different frequency and/or polarization. This routing allocates the total available bandwidth between parent and dependent beams. The system enables asynchronous communications between each hub and the satellite to maximize frequency re-use and the overall capacity of the system.

Claims

1. A satellite communications system for distributing information to user terminals, said system comprising:

a satellite in a geosynchronous orbit;

a first terminal located in a first spot beam produced by the satellite;

a fist hub located within the first spot beam produced by the satellite;

a second terminal located in a second spot beam produced by the satellite, the first spot beam being spatially isolated from the second spot beam;

a second hub located within the second spot beam produced by the satellite; and

a land-based communications network linking the first hub and second hub, said system comprising the first terminal communicating with the second terminal by transmitting the information along the first spot beam to the satellite, the satellite transmitting the information along the first beam to the first hub, the first hub routing the information over the land-based network to the second hub, the second hub transmitting the information along the second spot beam to the satellite, and the satellite transmitting the information along the second spot beam to the second terminal.

2. The system of claim 1, further comprising a third terminal located within the first beam, the first terminal and the third terminal being linked to the first hub, the first terminal communicating with the third terminal by transmitting the information along the first spot beam to the satellite, the satellite transmitting the information along the first beam to the first hub, the first hub transmitting the information along the first spot beam to the satellite, and the satellite transmitting the information along the first spot beam to the third terminal.

3. The system of claim 1, further comprising the first terminal transmitting the information along the first beam at a first frequency, and the satellite transmitting the information along the first beam at a second frequency.

4. The system of claim 1, further comprising the first terminal transmitting the information along the first beam at a first polarization, and the satellite transmitting the information along the first beam at a second polarization.

5. The system of claim 1, wherein the land-based communications network is further comprising a wide area network (WAN).