Apparatus and method for positioning single-offset zones in a spot beam coverage area to maximize call duration in a satellite-based communications network

• US 6,553,225 B1
• Filed: 10/14/1999
• Issued: 04/22/2003
• Est. Priority Date: 02/03/1999
• Status: Expired due to Term

• Current Assignee: Hughes Network Systems LLC (Echostar Corporation)
• Original Assignee: Hughes Electronics Corporation (Rtx Corporation)
• Inventors: Zhao, Wei, Roos, David
• Primary Examiner(s): Trost, William
• Assistant Examiner(s): LE, DANH C
• Application Number:
  US09/417,592
• Time in Patent Office: 1,286 Days
• Field of Search: 455/427, 455/429, 455/430, 455/12.1, 370/443, 370/348, 370/508
• US Class Current: 455/427
• CPC Class Codes: H04B 7/1851 Systems using a satellite or space-based relay H04B7/18508, H04B7/18521 take precedence; providing specific services H04B7/18523 - H04B7/18576
• CPC Class Codes: H04B 7/2041 Spot beam multiple access

Abstract

An apparatus and method, for use in a satellite-based communications network, for positioning offset zones in a spot beam coverage area to maximize call duration. The apparatus and method employs a spot beam segregator and an offset zone arranger. The spot beam segregator segregates a coverage area of a spot beam generated by a satellite in the network into at least one offset zone based on respective propagation time periods required for signals to travel between the satellite and respective different locations in the coverage area. The offset zone arranger arranges each offset zone such that each respective center of each one offset zone overlaps a respective geographical location in the coverage area, with each respective geographic location having a respective access terminal density greater than any other geographical region within its respective offset zone. The burst offset to be assigned to each single-offset zone is then determined based on the propagation delay at each respective highest access terminal density region in the respective zones. Therefore, within each offset zone, the amount of access terminals whose guard time between bursts received and transmitted is optimized, and call duration is effectively maximized.

Claims

1. An apparatus for increasing call duration time in a satellite-based communications network, comprising:

a spot beam segregator, adapted to segregate a coverage area of a spot beam generated by a satellite in said network into at least one offset zone based on respective propagation time periods required for signals to travel between said satellite and respective different locations in said coverage area; and

an offset zone arranger, adapted to arrange each of said at least one offset zone such that each respective center of each of said at least one offset zone overlaps a respective geographical location in said coverage area, each said respective geographic location having a respective access terminal density greater than any other geographical region within its respective offset zone.

2. An apparatus as claimed in claim 1, further comprising:

a burst offset calculator, adapted to calculate a burst offset in accordance with which bursts are received and transmitted by all access terminals in a said offset zone, based on a respective propagation delay period required for a signal to travel between said satellite and said respective geographic location within the said offset zone.

3. An apparatus as claimed in claim 1, further comprising:

an access terminal locator, adapted to determine in which of said at least one offset zone an access terminal resides based on a propagation delay time required for a signal transmitted from said access terminal to reach said satellite; and

a burst offset assignor which, based on the offset zone in which said access terminal resides as determined by said access terminal locator, assigns to said access terminal a burst offset time in accordance with which burst are received and transmitted by said access terminal.

4. An apparatus as claimed in claim 1, wherein:

said spot beam segregator segregates said coverage area into a plurality of offset zones; and

said offset zone arranger overlaps each respective center of each of said plurality of offset zones with a said respective geographical location in said coverage area.

5. An apparatus as claimed in claim 1, wherein:

said spot beam segregator segregates said coverage area into a plurality of offset zones, such that each said offset zone includes a portion of at least one adjacent offset zone.

6. An apparatus as claimed in claim 1, wherein said spot beam segregator is adapted to segregate said coverage area of said spot beam generated by said satellite which is a geo-synchronous satellite.

7. An apparatus for increasing call duration time in a satellite-based communications network including a satellite which generates a spot beam to form a spot beam coverage area which enables access terminals therein to communicate with said network, comprising:

an access terminal density determining apparatus, adapted to identify a location in at least one zone of said spot beam coverage area having a number of access terminals greater than any other location in said zone; and

a burst offset time assigning apparatus which is adapted to assign, based on a propagation delay of a signal propagating from said location to said satellite, a burst offset time in accordance with which burst are received and transmitted by every access terminal in said zone.

8. An apparatus as claimed in claim 7, wherein:

said access terminal density determining apparatus is adapted to identify a respective said location in each of a plurality of zones of said spot beam coverage area, each said respective location having a number of access terminals greater than any other location in its respective zone; and

said burst offset time assigning apparatus is adapted to assign a respective said burst offset time for each of said zones based on a respective propagation delay at each of their respective locations.

9. An apparatus as claimed in claim 7, further comprising:

an access terminal locator, adapted to determine in which of said at least one zone an access terminal resides based on a propagation delay time required for a signal transmitted from said access terminal to reach said satellite; and

wherein said burst offset time assigning apparatus assigns to said access terminal a said burst offset time based on the zone in which said access terminal resides as determined by said access terminal locator.

10. An apparatus as claimed in claim 7, wherein said satellite is a geo-synchronous satellite which generates said spot beam to form said spot beam coverage area;

and

said access terminal density determining apparatus is adapted to identify said location in said at least one zone at said spot beam coverage area found by said spot beam generated by said geo-synchronous satellite.

11. A method for increasing call duration time in a satellite-based communications network, comprising the steps of:

segregating a coverage area of a spot beam generated by a satellite in said network into at least one offset zone based on respective propagation time periods required for signals to travel between said satellite and respective different locations in said coverage area; and

arranging each of said at least one offset zone such that each respective center of each of said at least one offset zone overlaps a respective geographical location in said coverage area, each said respective geographic location having a respective access terminal density greater than any other geographical region within its respective offset zone.

12. A method as claimed in claim 11, further comprising the step of:

calculating a burst offset in accordance with which bursts are received and transmitted by all access terminals in a said offset zone, based on a respective propagation delay period required for a signal to travel between said satellite and said respective geographic location within the said offset zone.

13. A method as claimed in claim 11, further comprising the steps of:

determining in which of said at least one offset zone an access terminal resides based on a propagation delay time required for a signal transmitted from said access terminal to reach said satellite; and

assigning to said access terminal, based on the offset zone in which said access terminal resides as determined by said determining step, a burst offset time in accordance with which burst are received and transmitted by said access terminal.

14. A method as claimed in claim 11, wherein:

said segregating step segregates said coverage area into a plurality of offset zones; and

said arranging step overlaps each respective center of each of said plurality of offset zones with a said respective geographical location in said coverage area.

15. A method as claimed in claim 11, wherein:

said segregating step segregates said coverage area into a plurality of offset zones, such that each said offset zone includes a portion of at least one adjacent offset zone.

16. A method as claimed in claim 11 wherein said segregating step segregates said coverage area of said spot beam generated by said satellite which is a geo-synchronous satellite.

17. A method for increasing call duration time in a satellite-based communications network including a satellite which generates a spot beam to form a spot beam coverage area which enables access terminals therein to communicate with said network, comprising the steps of:

identifying a location in at least one zone of said spot beam coverage area having a number of access terminals greater than any other location in said zone; and

assigning a burst offset time in accordance with which burst are received and transmitted by every access terminal in said zone based on a propagation delay of a signal propagating from said location to said satellite.

18. A method as claimed in claim 17, wherein:

said identifying step identifies a respective said location in each of a plurality of zones of said spot beam coverage area, each said respective location having a number of access terminals greater than any other location in its respective zone; and

said assigning step assigns a respective said burst offset time for each of said zones based on a respective propagation delay at each of their respective locations.

19. A method as claimed in claim 17, further comprising the steps of:

determining in which of said at least one zone an access terminal resides based on a propagation delay time required for a signal transmitted from said access terminal to reach said satellite; and

wherein said assigning step assigns to said access terminal a said burst offset time based on the zone in which said access terminal resides as determined by said determining step.

20. A method as claimed in claim 17, wherein:

said satellite is a geo-synchronous satellite that generates said spot beam to form said spot beam coverage area; and

said identifying step identifies said location in said at least one zone of said spot beam coverage area formed by said spot beam generated by said geo-synchronous satellite.

21. A computer readable medium of instructions for increasing call duration time in a satellite-based communications network, comprising:

a first set of instructions, adapted to control said network to segregate a coverage area of a spot beam generated by a satellite in said network into at least one offset zone based on respective propagation time periods required for signals to travel between said satellite and respective different locations in said coverage area; and

a second set of instructions, adapted to control said network to arrange each of said at least one offset zone such that each respective center of each of said at least one offset zone overlaps a respective geographical location in said coverage area, each said respective geographic location having a respective access terminal density greater than any other geographical region within its respective offset zone.

22. A computer readable medium of instructions as claimed in claim 21, further comprising:

a third set of instructions, adapted to control said network to calculate a burst offset in accordance with which bursts are received and transmitted by all access terminals in a said offset zone, based on a respective propagation delay period required for a signal to travel between said satellite and said respective geographic location within the said offset zone.

23. A computer readable medium of instructions as claimed in claim 21, further comprising:

a fourth set of instructions, adapted to control said network to determine in which of said at least one offset zone an access terminal resides based on a propagation delay time required for a signal transmitted from said access terminal to reach said satellite; and

a fifth set of instructions, adapted to control said network to assign to said access terminal, based on the offset zone in which said access terminal resides as determined in accordance with said fourth set of instructions, a burst offset time in accordance with which burst are received and transmitted by said access terminal.

24. A computer readable medium of instructions as claimed in claim 21, wherein:

said first set of instructions is adapted to control said network to segregate said coverage area into a plurality of offset zones; and

said second set of instructions is adapted to control said network to overlap each respective center of each of said plurality of offset zones with a said respective geographical location in said coverage area.

25. A computer readable medium of instructions as claimed in claim 21, wherein:

said first set of instructions is adapted to control said network to segregate said coverage area into a plurality of offset zones, such that each said offset zone includes a portion of at least one adjacent offset zone.

26. A computer readable medium as claimed in claim 21, wherein said coverage area of said spot beam generated by said satellite is a geo-synchronous satellite.

27. A computer readable medium of instructions for increasing call duration time in a satellite-based communications network including a satellite which generates a spot beam to form a spot beam coverage area which enables access terminals therein to communicate with said network, comprising:

a first set of instructions, adapted to control said network to identify a location in at least one zone of said spot beam coverage area having a number of access terminals greater than any other location in said zone; and

a second set of instructions, adapted to control said network to assign a burst offset time in accordance with which burst are received and transmitted by every access terminal in said zone based on a propagation delay of a signal propagating from said location to said satellite.

28. A computer readable medium of instructions as claimed in claim 27, wherein:

said first set of instructions is adapted to control said network to identify a respective said location in each of a plurality of zones of said spot beam coverage area, each said respective location having a number of access terminals greater than any other location in its respective zone; and

said second set of instructions is adapted to control said network to assign a respective said burst offset time for each of said zones based on a respective propagation delay at each of their respective locations.

29. A computer readable medium of instructions as claimed in claim 27, further comprising:

a third set of instructions, adapted to control said network to determine in which of said at least one zone an access terminal resides based on a propagation delay time required for a signal transmitted from said access terminal to reach said satellite; and

wherein said second set of instructions is adapted to control said network to assign to said access terminal a said burst offset time based on the zone in which said access terminal resides as determined by said third set of instructions.

30. A computer readable medium as claimed in claim 27, wherein:

said satellite is a geo-synchronous satellite which generates said spot beam to form said spot beam coverage area, and

said network is adapted to identify said location in said at least one zone at said spot beam coverage area found by said spot beam generated by said geo-synchronous satellite.