Method and apparatus for spectrum sharing between satellite and terrestrial communication services using temporal and spatial synchronization

• US 5,584,046 A
• Filed: 11/04/1994
• Issued: 12/10/1996
• Est. Priority Date: 11/04/1994
• Status: Expired due to Fees

• Current Assignee: Cornell Research Foundation Incorporated (Cornell University)
• Original Assignee: Cornell Research Foundation Incorporated (Cornell University)
• Inventors: Martinez, Ren e D., Compton, Richard C.
• Primary Examiner(s): Pham, Chi H.
• Assistant Examiner(s): ARTHUR JEANGLAUDE, GERTRUDE
• Application Number:
  US08/336,193
• Time in Patent Office: 767 Days
• Field of Search: 455/12.1, 455/13.1, 455/13.2, 455/33.1, 455/56.1, 455/51.1, 370/31, 370/75, 370/103, 370/108, 370/95.3, 370/95.1, 370/104.1, 370/197, 375/354, 375/356
• US Class Current: 455/13.1
• CPC Class Codes: H04B 7/18513 Transmission in a satellite or space-based system

Abstract

A system and method for spatially and temporally synchronizing satellite (space based) and terrestrial (ground based) communications services using time division multiple access between the two types of service providers is given. Satellite and terrestrial communication services are assigned geographic cell boundaries to prevent conflicting simultaneous use of allocated spectrum. The spatial synchronization of cell boundaries can occur before hand by agreement between the users of the satellite and terrestrial services. This spatial synchronization may conform to geographic as well as political boundaries. Satellite and terrestrial services are assigned time slots to use a given spectrum within a given area. Methods are described for synchronizing the time slots to prevent interference between the services. Synchronization of LMDS and Teledesic services is described in the disclosure of a preferred embodiment.

Claims

1. A method for spatially and temporally synchronizing space based and ground based transmitting elements, comprising:

a) defining a first geographic area for coverage by a first ground based communications transmitter;

b) defining a second geographic area, adjacent said first geographic area, for coverage by a second ground based communications transmitter;

c) defining a third geographic area for coverage by a first space based communications transmitter, wherein said first and second geographic areas are situated within said third geographic area;

d) transmitting, from said first ground based transmitter, within said first geographic area, only when said first space based transmitter is not transmitting;

e) transmitting, from said second ground based transmitter, within said second geographic area, only when said first space based transmitter is not transmitting; and

f) transmitting, from said first space based transmitter, within said third geographic area, only when neither of said first and second ground based transmitters are transmitting.

2. The method of claim 1, further comprising:

transmitting from a second space based communications transmitter, only when said first space based transmitter is not transmitting;

wherein said first space based communications transmitter and said second space based communications transmitter are orbiting and moving in a track over the earth which includes said third geographic area.

3. The method of claim 1 wherein said first and second ground based communication transmitters are transmitting LMDS signals.

4. The method of claim 1 wherein said first space based transmitter is transmitting Teledesic system satellite transmitter signals.

5. A method for spatially and temporally synchronizing space based and ground based transmitting elements, comprising:

a) defining a first geographic area for coverage by a first ground based communications transmitter;

b) defining a second geographic area, contiguous to the first, for coverage by a second ground based communications transmitter;

c) defining a third geographic area, contiguous to the second, for coverage by a third ground based communications transmitter;

d) defining a fourth geographic area for coverage by a first space based spot beam, wherein said first and second geographic areas are situated within said fourth geographic area;

e) defining a fifth geographic area, contiguous to the fourth, for coverage by a second space based spot beam, wherein said third geographic area is situated within said fifth geographic area;

f) transmitting, from said first ground based transmitter, within said first geographic area, only when said first space based spot beam is not transmitting a downlink beam;

g) transmitting, from said second ground based transmitter, within said second geographic area, only when said first space based spot beam is not transmitting a downlink beam;

h) transmitting, from said third ground based transmitter, within said third geographic area, only when said second space based spot beam is not transmitting a downlink beam;

i) transmitting, from said first space based spot beam, within said fourth geographic area, only when said first and second ground based transmitters are not transmitting; and

j) transmitting, from said second space based spot beam, within said fifth geographic area, only when neither of said third ground based transmitter and said first space based spot beam are transmitting.

6. The method of claim 5 wherein said first, second and third ground based communication transmitters are transmitting LMDS signals.

7. The method of claim 5 wherein said first and second space based spot beams are transmitting Teledesic system satellite transmitter signals.

8. A system for spatially and temporally synchronizing space based and ground based transmitting elements, comprising:

a) a first ground based communications transmitter covering a first geographic area;

b) s second ground based communications transmitter covering a second geographic area, adjacent said first geographic area;

c) a first satellite having a first space based communications transmitter for covering a third geographic area, wherein said first and second geographic areas are situated within said third geographic area;

d) first synchronizing means for transmitting, from said first ground based transmitter, within said first geographic area, only when said first space based transmitter is not transmitting;

e) second synchronizing means for transmitting, from said second ground based transmitter, within said second geographic area, only when said first space based transmitter is not transmitting; and

f) third synchronizing means for transmitting, from said first space based transmitter, within said third geographic area, only when neither of said first and second ground based transmitters are transmitting.

9. The system of claim 8 further comprising:

a first earth station uplink transmitter, located within said first geographic area, for communication with a receiver on said first satellite, and

fourth synchronizing means for transmitting from said first earth station uplink transmitter, to said first satellite receiver, only when said first ground based transmitter is not transmitting.

10. The system of claim 8, further comprising:

a second satellite including a second space based communications transmitter including fifth synchronizing means for transmitting only when said first space based transmitter is not transmitting;

wherein said first satellite and said second satellite are in orbit and moving in a track over the earth which includes said second geographic area.

11. The system of claim 8 wherein said first and second ground based communication transmitters are LMDS transmitters having synchronizing receivers.

12. The method of claim 8 wherein said first space based transmitter comprises a Teledesic system satellite transmitter.