Communications system and method employing forward satellite links using multiple simultaneous data rates

• US 6,847,801 B2
• Filed: 08/30/2001
• Issued: 01/25/2005
• Est. Priority Date: 08/30/2001
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: de La Chapelle, Michael, Parkman, David S.
• Primary Examiner(s): Corsaro, Nick
• Assistant Examiner(s): Orgad, Edan
• Application Number:
  US09/943,679
• Publication Number:
  US 20030045231A1
• Time in Patent Office: 1,244 Days
• Field of Search: 455/12.1, 455/13.1, 455/427, 455/500, 455/414.1, 455/422.1, 455/431, 455/456.1, 455/456.3, 455/456.5, 455/13.2, 455/67.11
• US Class Current: 455/12.1
• CPC Class Codes: H04B 7/18508 with satellite system used as relay, i.e. aeronautical mobile satellite service

Abstract

A communication system and method for transmitting data to mobile platforms using multiple simultaneous channels operating at multiple data rates. Each mobile receiver has the capability to receive multiple transmit channels at multiple data rates. Aircraft report their position to a ground based controller which determines which communication channel can be operated without substantial loss of data. Data packets destined for each aircraft are preferably routed to the highest data rate channel that can be received by that aircraft without substantial loss of data. This maximizes the overall system efficiency and throughput. High priority and mission critical data may be transmitted to the aircraft using low data rate channels to increase link availability.

Claims

1. A communication system for transmitting data from a spaced based satellite to at least one mobile platform using multiple data rate channels, comprising;

a space based satellite having a plurality of transmitters operating at a plurality of data rates;

said mobile platforms each having a plurality of receivers, operating simultaneously at a plurality of data rates to receive transmitted data from said transmitters;

said system being operable to transmit data to said mobile platform on more than one of a plurality of data rate channels and operating to select a particular said data rate channel for transmitting data to said mobile platform based on at least a geographic location of said mobile platform; and

wherein said system selects a particular one of said data rate channels for transmitting said data to said mobile platform in a manner that maximizes overall communication throughput.

2. The system of claim 1 wherein said mobile platform periodically transmits position reports concerning its position to said space based satellite.

3. The system of claim 2, wherein said position reports are used to estimate a maximum data rate at which said communication channel can be operated without substantial loss of transmitted data.

4. The system of claim 3, wherein said data destined for said particular mobile platform is switched to a highest one of said data rate channels that can be operated without substantial loss of said data being experienced by said mobile platform.

5. The system of claim 4, wherein switching of said data is accomplished in a router located in one of said space based satellite and a ground based entity.

6. A space linked communications system comprising:

a base communications system operable to transmit information on a selected one of a plurality of channels at a selected one of a plurality of different information transmission rates;

a space based transponder system for transponding said information received over said selected one of said plurality of communications channels;

a mobile communications system adapted to be carried on-board a mobile platform and being operable to communicate with said transponder system over said plurality of communications channels;

wherein said selected information rate is determined in part by a geographic location of said mobile platform within a coverage region; and

wherein said selected information transmission rate is modified to a different one of said transmission rates, in real time, as said mobile platform traverses said coverage region, to thereby increase efficiency and throughput of the communications link between said ground based and mobile communications systems.

7. The system of claim 6, wherein said ground based communications system controls the selection of said information transmission rate.

8. The system of claim 6, wherein said mobile communications system includes a plurality of receivers, each said receiver being tuned to an associated one of said plurality of communications channels.

9. The system of claim 6, wherein said ground based segment includes:

a plurality of transmitters, each said transmitter being adapted to transmit said information over an associated one of said channels at a pre-selected information transmission rate; and

a router for directing said information from a content source to a selected one of said transmitters.

10. The system of claim 9, further comprising a router carried on said mobile platform for receiving said information received by said receivers to an information processing component carried on said mobile platform.

12. The system of claim 6, wherein said ground based system selects said information trans rate to maintain a minimum predetermined bit error rate for said information.

13. The system of claim 6, wherein said ground based system includes a router for routing packets of said information to be transmitted to said mobile system only to a designated one of said transmitters thereof, thereby providing a unicast transmission of said packets to said mobile system.

14. The system of claim 6, wherein each said information transmission rate of said transmitters are associated with a predetermined portion of said geographic coverage area.

11. A space linked communications system for providing a communications link having a variable information transmission rate, said system comprising:

a ground based system having a plurality of transmitters, each of said transmitters being adapted to transmit information at a predetermined information transmission rate over a corresponding one of a plurality of channels;

a satellite based transponder system for transponding information received from said ground based system over a predetermined geographic coverage area;

a mobile communications system adapted to be carried on a mobile platform and having a receiver system including a plurality of receivers each tuned to an associated one of said transmission channels, for receiving said information transponded by said satellite based transponder system;

wherein an initial information transmission rate for said information is determined by said ground based system based at least on a location of said mobile platform within said geographic coverage area; and

wherein said information transmission rate is varied by said ground based system based at least in part on the location of said mobile platform as said mobile platform traverses said coverage region to maintain to said information transmission rate at a value which maximizes the efficiency of said communications link between said mobile communications system and said ground based system without causing said communications link to be broken.

15. A space linked communication system for communicating information to a plurality of mobile platforms travelling within a geographic coverage region, said system comprising:

a ground based system for transmitting information over a plurality of communication channels, each said communication channel having a predetermined information transmission rate;

a mobile communications system disposed on each said mobile platform, each said mobile communications system being operable to receive information on a plurality of independent channels;

wherein said ground based system operates to monitor a location of each said mobile platform and selects which said communication channel is to be used with each said mobile platform, based upon the location of each said mobile platform, to maximize a transmission of said information while maintaining a minimum signal quality level.

16. The system of claim 15, wherein said ground based system comprises a router for routing information to be transmitted to a specific one of said mobile platforms via a specific one of said communication channels.

17. The system of claim 16, wherein said ground based system includes a plurality of transmitters for transmitting said information over said communication channels.

18. The system of claim 15, wherein said ground based system controls the transmission of said information over said communication channels such that a predetermined bit error rate is not exceeded for any information transmitted to said mobile platforms.

19. A method for conducting communications between a ground based communications system and a mobile platform, comprising the steps of:

having the mobile platform transmit information to the ground system indicative of a position of said mobile platform within a coverage region;

using the ground system to determine which one of a plurality of information transmission rates to use in transmitting information to said mobile platform, based on the location of said mobile platform within said coverage region, and selecting an information transmission rate being that ensures that a predetermined transmission error rate of said information will not be exceeded during transmissions of said information;

using said ground based system to transmit information to said mobile platform at said selected information transmission rate via a satellite based transponder; and

using a receiver on said mobile platform to receive said information on one of a plurality of communication channels associated with said selected information transmission rate.

20. The method of claim 19, wherein said predetermined error transmission rate comprises a predetermined bit error rate for said transmitted information.

21. The method of claim 20, wherein said mobile platform uses one of a plurality of independent receivers to receive said transmitted information.