Satellite communication system

• US 6,643,273 B2
• Filed: 12/19/2000
• Issued: 11/04/2003
• Est. Priority Date: 10/08/1997
• Status: Expired due to Fees

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Chao, William W.
• Primary Examiner(s): MARCELO, MELVIN C
• Application Number:
  US09/739,329
• Publication Number:
  US 20010000455A1
• Time in Patent Office: 1,050 Days
• Field of Search: 370/310, 370/316, 370/464, 370/466, 370/467, 370/469, 370/473, 370/535, 370/536, 370/537, 370/902, 370/912, 370/916, 370/465, 370/470, 370/471
• US Class Current: 370/316
• CPC Class Codes: H04B 7/18589 Arrangements for controlling an end to end session, i.e. for initialising, synchronising or terminating an end to end link

Abstract

A communication system for multimedia having a plurality of mobile and fixed terminals. The system links terrestrial communication systems together through a network of non-geostationary satellites. The terrestrial communication systems include fixed location, mobile, and portable communication systems.

The satellites communicate with a communication protocol similar to terrestrial communication protocols. This reduces protocol conversion.

The source and destination addressing uses static terrestrial cells for the uplink and the downlink.

Terminal data stream is segmented into communication packets at the terrestrial gateway based on the uplink satellite'"'"'s determination of system parameters. The non-geostationary satellites route the communication packets the satellites. The control satellite dynamically balances up-links and down-links in the terrestrial areas with over-lapping satellite coverage.

Claims

1. A method of providing satellite communication among a source terminal, a plurality of communication satellites and a destination terminal, the method comprising:

determining an optimal packet length;

creating packets having the optimal length;

determining an optimal route for each packet among the communication satellites from the source terminal to the destination terminal;

transmitting at least one of the created packets from the source terminal to a source gateway utilizing a structured communication protocol;

transmitting at least one of the created packets from the source gateway to a first of the communications satellites, among the communications satellites, and to a destination gateway utilizing a satellite communication protocol substantially similar to the structured communication protocol; and

transmitting at least one of the created packets from the destination gateway to the destination terminal utilizing the structured communication protocol.

2. The method according to claim 1, wherein the source terminal is mobile.

3. The method according to claim 1, wherein the source terminal is fixed.

4. The method according to claim 1, wherein the source gateway is mobile.

5. The method according to claim 1, wherein the source gateway is fixed.

6. The method according to claim 1, wherein the destination terminal is mobile.

7. The method according to claim 1, wherein the destination gateway is mobile.

8. The method according to claim 1, wherein the destination gateway is fixed.

9. The method according to claim 1, wherein the optimal packet length is determined by a first of the communications satellites.

10. The method according to claim 9, wherein the optimal packet length is based upon one or more parameters selected from the group consisting of link error rate, quality of service, priority, cost of service, and a number of available links.

11. The method according to claim 1, wherein each satellite determines an optimal route for each packet that is transmitted to it.

12. The method according to claim 1, wherein each packet comprises a contact switch marker, routing information, payload information, an error correction code and payload data.

13. The method according to claim 12, wherein the contact switch marker comprises an empty/full code and an entry point.

14. The method according to claim 13, wherein the empty/full code indicates whether the entry has been previously determined.

15. The method according to claim 13, wherein when a satellite receives a packet with an empty code the satellite determines the entry point and places it in the packet.

16. The method according to claim 15, wherein after determining an entry point for a packet, subsequent satellites to which the packet is transmitted begin a routing search from the entry point.

17. The method according to claim 15, further comprising:

updating the entry point after each satellite completes the optimal route determination.

18. The method according to claim 1, wherein each satellite determines the optimal route utilizing one or more routing information selected from the group consisting of a destination cell, a destination cell address, a payload length, a hop count, a priority, a flow label, and a version.

19. The method according to claims 18, wherein the destination cell address comprises an address of a destination gateway.

20. The method according to claim 1, further comprising:

assigning a priority to a communication stream.

21. The method according to claim 20, further comprising:

routing higher priority communication streams to shorter or more reliable routes.

22. The method according to claim 1, wherein the source gateway and terminal are contained in a single apparatus.

23. The method according to claim 1, wherein the source gateway and terminal are contained in separate apparatus.

24. The method according to claim 1, further comprising:

reassembling the packets in a desired sequence after receipt by the destination gateway.

25. The method according to claim 1, wherein the source gateway requests an optimal payload length from the first satellite that is to receive the packet.

26. The method according to claim 25, wherein the satellite determines the optimal packet length based upon one or more parameters selected from the group consisting of system parameters comprising satellites available to link the source and the destination, loads on each available satellite, error rate of each available satellite, cost of service, and number of hops required and communication parameters comprising priority, hop count, and amount of data to be transferred.

27. The method according to claim 1, wherein a route of the packet among the satellites is determined independently at each satellite at least along the route taken by the packet.

28. The method according to claim 1, wherein a control satellite manages links between the source and the satellites.

29. The method according to claim 28, wherein the control satellite determines which satellites have overlapping coverage areas and determines which satellite provides a route with the source and destination gateways.

30. The method according to claim 28, wherein the control satellite determines the route among the satellites based upon one or more parameters selected from the group consisting of traffic density, transport delays, quality of service, computational capacity, lack of coverage timing, cost of service, and error rate in static cells.

31. The method according to claim 28, wherein the control satellite determines over lapping coverage areas based upon one or more parameters selected from the group consisting of logical user identifications of terminal, connection time of each link, satellite identification, end of coverage time per satellite, traffic status, and access code.

32. The method according to claim 28, wherein if no control satellite exists in a static cell a first satellite entering a static cell assigns itself as the control satellite.

33. The method according to claim 28, wherein as each satellite enters a static cell it transmits its satellite information to the control satellite for the static cell.

34. The method according to claim 33, wherein the satellite information comprises time of each terrestrial link, satellite identification, end of coverage time per gateway, and access codes.

35. The method according to claim 28, wherein as preparation for the control satellite leaving a static cell it assigns another satellite as the replacement control satellite.

36. The method according to claim 35, wherein the replacement control satellite is the satellite with a longest remaining coverage time in the static cell.

37. A satellite communication system, comprising:

a source terminal operable to determine an optimal route for each packet among the communication satellites from the source terminal to a destination terminal and operable to transmit each packet from the source terminal to a gateway utilizing a structured communication protocol and to a first of a plurality of communications satellites utilizing a satellite communication protocol substantially similar to the structured communication protocol;

a plurality of communications satellites operable to transmit each packet among the communications satellites and to a destination gateway utilizing the satellite communication protocol; and

the destination gateway operable to transmit each packet from the destination gateway to the destination terminal utilizing the structured communication protocol.

38. A satellite communication system, comprising:

a source terminal operable to transmit data packets to a source gateway utilizing a structured communication protocol;

the source gateway operable to transmit the data packets to a first of a plurality of communications satellites utilizing a satellite communication protocol substantially similar to the structured communication protocol;

the plurality of communications satellites operable to transmit each of the data packets to a destination gateway via at least some of the other of the plurality of communications satellites utilizing the satellite communication protocol, the plurality of communications satellites configured to determine an optimal route for each of the data packets; and

the destination gateway operable to transmit each packet from the destination gateway to the destination terminal utilizing the structured communication protocol.

39. The system according to claim 38, wherein the source terminal is mobile.

40. The system according to claim 38, wherein the source terminal is fixed.

41. The system according to claim 38, wherein the source gateway is mobile.

42. The system according to claim 38, wherein the source gateway is fixed.

43. The system according to claim 38, wherein the destination terminal is mobile.

44. The system according to claim 38, wherein the destination gateway is mobile.

45. The system according to claim 38, wherein the destination gateway is fixed.

46. The system according to claim 38, wherein an optimal packet length is determined by the first of the plurality of communications satellites.

47. The system according to claim 46, wherein the optimal packet length is based upon one or more parameters selected from the group consisting of link error rate, quality of service, priority, cost of service, and a number of available links.

48. The system according to claim 38, wherein each of the plurality of communications satellites determines an optimal route for each data packet that is transmitted to it.

49. The system according to claim 38, wherein each data packet comprises a contact switch marker, routing information, payload information, an error correction code and payload data.

50. The system according to claim 49, wherein the contact switch marker comprises an empty/full code and an entry point.

51. The system according to claim 50, wherein the empty/full code indicates whether the entry has been previously determined.

52. The system according to claim 50, wherein when a satellite receives a packet with an empty code the satellite determines the entry point and places it in the packet.

53. The system according to claim 52, wherein after an entry point for a packet is determined, subsequent satellites to which the packet is transmitted begin a routing search from the entry point.

54. The system according to claim 52, wherein each satellite updates the entry point after it determines the optimal route.

55. The system according to claim 38, wherein each of the plurality of communications satellites determines the optimal route utilizing one or more routing information selected from the group consisting of a destination cell, a destination cell address, a payload length, a hop count, a priority, a flow label, and a version.

56. The system according to claim 55, wherein the destination cell address comprises an address of a destination gateway.

57. The system according to claim 38, wherein a communication stream comprising a plurality of data packets is assigned a priority.

58. The system according to claim 57, wherein higher priority communication streams are routed to shorter or more reliable routes.

59. The system according to claim 38, wherein the source gateway and the source terminal are contained in a single apparatus.

60. The system according to claim 38, wherein the source gateway and the source terminal are contained in separate apparatus.

61. The system according to claim 38, wherein the destination gateway reassembles the data packets in a desired sequence after receiving the data packets.

62. The system according to claim 38, wherein the source gateway requests an optimal payload length from the first of the plurality of communications satellites.

63. The system according to claim 62, wherein the first of the communications satellites determines the optimal packet length based upon one or more system parameters select from the group consisting of satellites available to link the source and the destination, loads on each available satellite, error rate of each available satellite, cost of service, and number of hops required and communication parameters comprising priority, hop count, and amount of data to be transferred.

64. The system according to claim 38, wherein a route of the data packets among the plurality of communications satellites is determined independently at each of the communications satellites at least along the route taken by the data packets.

65. The system according to claim 38, wherein a control satellite manages links between the source and the communications satellites.

66. The system according to claim 65, wherein the control satellite determines which communications satellites have over-lapping coverage areas and determines which satellite provides a route with the source and the destination gateways.

67. The system according to claim 65, wherein the control satellite determines the route among the communications satellites based upon one or more parameters selected from the group consisting of traffic density, transport delays, quality of service, computational capacity, lack of coverage timing, cost of service, and error rate in static cells.

68. The system according to claim 65, wherein the control satellite determines over-lapping coverage areas based upon one or more parameters selected from the group consisting of logical user identifications of terminals, connection time of each link, satellite identification, end of coverage time per satellite, traffic status, and access code.

69. The system according to claim 65, wherein if no control satellite exists in a static cell a first communications satellite entering a static cell assigns itself as the control satellite.

70. The system according to claim 65, wherein as each communications satellite enters a static cell it transmits its satellite information to the control satellite for the static cell.

71. The system according to claim 70, wherein the satellite information comprises time of each terrestrial link, satellite identification, end of coverage time per gateway, and access codes.

72. The system according to claim 65, wherein the control satellite assigns another satellite as the replacement control satellite prior to leaving the static cell.

73. The system according to claim 72, wherein the replacement control satellite is the satellite with a longest remaining coverage time in the static cell.