Apparatus and method for grouping carriers to minimize the occurrence of call blocking in a satellite-based communications network

• US 6,332,069 B1
• Filed: 02/10/1999
• Issued: 12/18/2001
• Est. Priority Date: 02/10/1999
• Status: Expired due to Term

• Current Assignee: Hughes Network Systems LLC (Echostar Corporation)
• Original Assignee: Hughes Electronics Corporation (AT&T, Inc.)
• Inventors: Zhao, Wei, Arnold, Steven, Roos, Dave, Noerpel, Anthony
• Primary Examiner(s): Bost, Dwayne
• Assistant Examiner(s): Trinh, Sonny
• Application Number:
  US09/244,970
• Time in Patent Office: 1,042 Days
• Field of Search: 455/12.1, 455/13.2, 455/63, 455/427, 455/429, 455/13.1, 455/430, 455/422, 455/446, 342/354, 342/154, 342/356
• US Class Current: 455/12.1
• CPC Class Codes: H04B 7/18539 Arrangements for managing radio, resources, i.e. for establishing or releasing a connection
• CPC Class Codes: H04B 7/2041 Spot beam multiple access

Abstract

An apparatus and method, for use in a satellite-based communications network, for minimizing blocking of communication between the network and access terminals resulting from differences in the signal propagation delays for the access terminals due to their different locations within a coverage area serviced by a spot beam generated by a satellite in the network. The apparatus includes a spot beam segregator which segregates a coverage area of the spot beam into at least one coverage zone based on the maximum and minimum propagation delay experienced by access terminals within the coverage area of the spot beam. The apparatus further includes a carrier grouper which groups the carrier into a number of groups corresponding to the number of offset zones, and assigns each carrier group to a respective one of the coverage zones. The number of carriers assigned to each carrier group is proportional to the estimated number of access terminals located in the respective coverage zone to which the carrier group is assigned. The apparatus assigns a respective burst offset to each respective coverage zone so that signals being transmitted by the satellite and access terminals within the coverage zone are transmitted in accordance with the same burst offset. Accordingly, burst signals are arranged efficiently in the TDMA time frames being transmitted over the carriers between the satellite and access terminals, which therefore minimizes call blocking.

Claims

1. An apparatus, for use in a satellite-based communications network, for grouping a plurality of carriers of a carrier resource pool assigned to a spot beam generated by a satellite in said network, and over which signal bursts are transmitted between said satellite and at least one user terminal located in a coverage area of said spot beam, said apparatus comprising:

a spot beam segregator which segregates said coverage area 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 carrier grouper which groups said carriers into an amount of carrier groups corresponding to an amount of said at least one offset zone, and assigns each of said carrier groups to service a respective one of said at least one offset zone.

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

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

said carrier grouper groups said carriers into a plurality of carrier groups corresponding to said plurality of offset zones, and assigns each of said carrier groups to a respective one of said offset zones.

3. 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.

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

said spot beam segregator segregates said coverage area into an amount of offset zones equal to a positive integer greater than one, such that one of said offset zones includes a mid-delay point of said coverage area, and the other of said offset zones are equally distributed on opposite sides of said one of said offset zones, said mid-delay point representing a location in said coverage area at which an amount of propagation time required for a signal to travel between said mid-delay point and said satellite has a value midway between a maximum value representing a maximum amount of propagation time required for a signal to travel between a first location in said coverage area and said satellite and a minimum value representing a minimum amount of propagation time required for a signal to travel between a second location in said coverage area and said satellite.

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

said spot beam segregator segregates said coverage area into a single offset zone; and

said carrier grouper groups said carriers into a single carrier group and assigns said carrier group to said single offset zone.

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

said spot beam segregator segregates said coverage area based on at least one of a maximum propagation time required for a signal to travel between said satellite and a first location in said coverage area and a minimum propagation time required for a signal to travel between said satellite and a second location in said coverage area.

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

a burst offset assignor which assigns a respective burst offset to each respective said offset zone, each said respective burst offset representing a period of time required between a start of transmission of a signal burst by said satellite to a user terminal over a carrier in said carrier group assigned to said respective offset zone and a start of reception by said satellite of a signal burst transmitted by said user terminal over another carrier in said carrier group.

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

said carrier grouper groups a respective amount of said carriers into each of said respective carrier groups based on respective values assigned to said offset zone, each of said values representing an amount of user terminals adapted for use in said respective offset zone.

9. An apparatus, for use in a satellite-based communications network, for setting timings at which signal bursts are transmitted between a satellite in said network and at least one user terminal in a coverage area of a spot beam generated by said satellite, said apparatus comprising:

a spot beam segregator which segregates said coverage area 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 burst offset assignor which assigns a respective burst offset to each respective said offset zone, each said respective burst offset representing a period of time required between a start of transmission of a signal burst by said satellite to a user terminal located in said respective offset zone and a start of reception by said satellite of a signal burst transmitted by said user terminal in said respective offset zone.

10. An apparatus as claimed in claim 9, wherein:

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

11. An apparatus as claimed in claim 10, wherein:

each said offset zone includes a portion of at least one adjacent offset zone.

12. An apparatus as claimed in claim 9, wherein:

said spot beam segregator segregates said coverage area into an amount of offset zones equal to a positive integer greater than one, such that one of said offset zones includes a mid-delay point of said coverage area, and the other of said offset zones are equally distributed on opposite sides of said one of said offset zones, said mid-delay point representing a location in said coverage area at which an amount of propagation time required for a signal to travel between said mid-delay point and said satellite has a value midway between a maximum value representing a maximum amount of propagation time required for a signal to travel between a first location in said coverage area and said satellite and a minimum value representing a minimum amount of propagation time required for a signal to travel between a second location in said coverage area and said satellite.

13. An apparatus as claimed in claim 9, wherein:

said spot beam segregator segregates said coverage area into a single offset zone.

14. An apparatus as claimed in claim 9, wherein:

said spot beam segregator segregates said coverage area based on at least one of a maximum propagation time required for a signal to travel between said satellite and a first location in said coverage area and a minimum propagation time required for a signal to travel between said satellite and a second location in said coverage area.

15. A method for grouping a plurality of carriers of a carrier resource pool assigned to a spot beam generated by a satellite in a satellite-based communications network, and over which signal bursts are transmitted between said satellite and at least one user terminal located in a coverage area of said spot beam, said method comprising the steps of:

segregating said coverage area 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;

grouping said carriers into an amount of carrier groups corresponding to an amount of said at least one offset zone; and

assigning each of said carrier groups to service a respective one of said at least one offset zone.

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

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

said grouping step groups said carriers into a plurality of carrier groups corresponding to said plurality of offset zones; and

said assigning step assigns each of said carrier groups to a respective one of said offset zones.

17. A method as claimed in claim 15, 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.

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

said segregating step segregates said coverage area into an amount of offset zones equal to a positive integer greater than one, such that one of said offset zones includes a mid-delay point of said coverage area, and the other of said offset zones are equally distributed on opposite sides of said one of said offset zones, said mid-delay point representing a location in said coverage area at which an amount of propagation time required for a signal to travel between said mid-delay point and said satellite has a value midway between a maximum value representing a maximum amount of propagation time required for a signal to travel between a first location in said coverage area and said satellite and a minimum value representing a minimum amount of propagation time required for a signal to travel between a second location in said coverage area and said satellite.

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

said segregating step segregates said coverage area into a single offset zone;

said grouping step groups said carriers into a single carrier group; and

said assigning step assigns said carrier group to said single offset zone.

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

said segregating step segregates said coverage area based on at least one of a maximum propagation time required for a signal to travel between said satellite and a first location in said coverage area and a minimum propagation time required for a signal to travel between said satellite and a second location in said coverage area.

21. A method as claimed in claim 15, further comprising a step of:

assigning a respective burst offset to each respective said offset zone, each said respective burst offset representing a period of time required between a start of transmission of a signal burst by said satellite to a user terminal over a carrier in said carrier group assigned to said respective offset zone and a start of reception by said satellite of a signal burst transmitted by said user terminal over another carrier in said carrier group.

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

said grouping step groups a respective amount of said carriers into each of said respective carrier groups based on respective values assigned to said offset zone, each of said values representing an amount of user terminals adapted for use in said respective offset zone.

23. A method for setting timings at which signal bursts are transmitted between a satellite in a satellite-based communications network and at least one user terminal in a coverage area of a spot beam generated by said satellite, said method comprising the steps of:

segregating said coverage area 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

assigning a respective burst offset to each respective said offset zone, each said respective burst offset representing a period of time required between a start of transmission of a signal burst by said satellite to a user terminal located in said respective offset zone and a start of reception by said satellite of a signal burst transmitted by said user terminal in said respective offset zone.

24. A method as claimed in claim 23, wherein:

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

25. A method as claimed in claim 24, wherein:

each said offset zone includes a portion of at least one adjacent offset zone.

26. A method as claimed in claim 23, wherein:

said segregating step segregates said coverage area into an amount of offset zones equal to a positive integer greater than one, such that one of said offset zones includes a mid-delay point of said coverage area, and the other of said offset zones are equally distributed on opposite sides of said one of said offset zones, said mid-delay point representing a location in said coverage area at which an amount of propagation time required for a signal to travel between said mid-delay point and said satellite has a value midway between a maximum value representing a maximum amount of propagation time required for a signal to travel between a first location in said coverage area and said satellite and a minimum value representing a minimum amount of propagation time required for a signal to travel between a second location in said coverage area and said satellite.

27. A method as claimed in claim 23, wherein:

said segregating step segregates said coverage area into a single offset zone.

28. A method as claimed in claim 23, wherein:

said segregating step segregates said coverage area based on at least one of a maximum propagation time required for a signal to travel between said satellite and a first location in said coverage area and a minimum propagation time required for a signal to travel between said satellite and a second location in said coverage area.