Method of controlling a satellite communication system, a timing unit, and a control unit of a timing unit

• US 20040021602A1
• Filed: 05/20/2003
• Published: 02/05/2004
• Est. Priority Date: 05/22/2002
• Status: Active Grant

• Current Assignee: RPX Corporation
• Original Assignee: Nokia Corporation
• Inventors: Martikkala, Risto, Niemenmaa, Jarko, Weckstrom, Mikko
• Granted Patent: US 7,317,895 B2
• Time in Patent Office: Days
• US Class Current: 342/427
• CPC Class Codes: H04B 7/18532 Arrangements for managing transmission, i.e. for transporting data or a signalling message
• CPC Class Codes: H04W 56/001 Synchronization between nodes

Abstract

A method of controlling a satellite communication system, a timing unit, and a control unit of a timing unit. The method comprises dividing the coverage area of the satellite communication system into one or several geographical areas; positioning one or several timing units in at least one geographical area; determining which of the satellites of the satellite communication system are visible in each particular geographical area; controlling the timing unit with a control unit, in order to minimize the time difference within the system, to listen to one or several satellites visible in each particular geographical area, the signals received from the satellites by the timing unit fulfilling a predetermined condition; synchronizing a predetermined number of geographical areas with each other by means of the control unit of the system such that the time difference within the system is minimized in a predetermined combination area of geographical areas.

Claims

1. A method for controlling a satellite communication system, which satellite communication system comprises satellites and ground network system devices positioned on earth, the method comprising:

dividing the coverage area of the satellite communication system into one or several geographical areas;

positioning one or several timing units in at least one geographical area;

determining which of the satellites of the satellite communication system are visible in each particular geographical area;

controlling the timing unit with a control unit, in order to minimize the time difference within the system, to listen to one or several satellites visible in each particular geographical area, the signals received from the satellites by the timing unit fulfilling a predetermined condition.

3. A method according to claim 1, wherein the geographical area is a radio cell of a cellular system.

4. A method according to claim 1, wherein the satellites to be listened to are determined with measurements of the timing unit.

5. A method according to claim 1, wherein the control unit is positioned in a unit controlling the base transceiver stations of the ground network.

6. A method according to claim 1, wherein the timing unit is positioned in a base transceiver station or a radio mast of the ground network system.

7. A method according to claim 1, further comprising selecting that satellite from which the timing unit receives the strongest signal to be listened to.

8. A method according to claim 1, further comprising selecting those satellites, received by the timing unit, whose signal strengths exceed a set threshold value to be listened to.

9. A method according to claim 1, further comprising selecting those satellites, received by the timing unit, whose signal strengths exceed a set threshold value during the whole of the 24 hours to be listened to.

10. A method according to claim 1, wherein the control unit gives a command about which satellites the timing unit will not listen to.

11. A method according to claim 1, wherein the control unit gives a command about which satellites the timing unit will listen to.

2. A method for controlling a satellite communication system, which satellite communication system comprises satellites and ground network system devices positioned on earth, the method comprising:

dividing the coverage area of the satellite communication system into one or several geographical areas;

positioning one or several timing units in at least one geographical area;

determining which of the satellites of the satellite communication system are visible in each particular geographical area;

controlling the timing unit with a control unit, in order to minimize the time difference within the system, to listen to one or several satellites visible in each particular geographical area, the signals received from the satellites by the timing unit fulfilling a predetermined condition;

synchronizing a predetermined number of geographical areas with each other by means of the control unit of the system in such a way that the time difference within the system is minimized in a predetermined combination area of geographical areas.

12. A method according to claim 2, further comprising synchronizing a predetermined number of geographical areas with each other with the control unit of the system in such a way that the control units determine the timing units to listen to at least substantially the same satellites.

13. A control unit of a timing unit in a satellite communication system comprising:

the control unit comprises means for determining which of the satellites of the satellite communication system are visible in each particular geographical area;

the control unit comprises means for controlling the timing unit, in order to minimize the time difference within the system, to listen to one or several of the satellites visible in each particular geographical area, the signals received from the satellites by the timing unit fulfilling a predetermined condition.

15. A control unit according to claim 13, wherein the control unit is positioned in a unit controlling the base transceiver stations of the ground network system.

16. A control unit according to claim 13, wherein that satellite from which the timing unit receives the strongest signal is selected to be listened to.

17. A control unit according to claim 13, wherein those satellites, received by the timing unit, whose signal strengths exceed a set threshold value are selected to be listened to.

18. A control unit according to claim 13, wherein those satellites, received by the timing unit, whose signal strengths exceed a set threshold value during the whole of the 24 hours are selected to be listened to.

19. A control unit according to claim 13, wherein the control unit gives a command about which satellites the timing unit will not listen to.

20. A control unit according to claim 13, wherein the control unit gives a command about which satellites the timing unit will listen to.

21. A control unit according to claim 13, wherein the control unit receives and interprets a signal transmitted by the timing unit and containing measurement information.

14. A control unit of a timing unit in a satellite communication system comprising:

the control unit comprises means for determining which of the satellites of the satellite communication system are visible in each particular geographical area;

the control unit comprises means for controlling the timing unit, in order to minimize the time difference within the system, to listen to one or several of the satellites visible in each particular geographical area, the signals received from the satellites by the timing unit fulfilling a predetermined condition;

the control unit comprises means for synchronizing a predetermined number of geographical areas with each other in such a way that the time difference within the system is minimized in a predetermined combination area of geographical areas.

22. A timing unit of a satellite communication system comprising:

the timing unit comprises means for receiving control commands from the control unit of the timing unit in order to minimize the time difference within the system, the control commands being used to control the timing unit to listen to one or several of the satellites visible in each particular geographical area, the signals received from the satellites fulfilling a predetermined condition.

23. A timing unit according to claim 22, wherein the satellites to be listened to are determined by means of measurements.

24. A timing unit according to claim 22, wherein the control unit is positioned in a unit controlling the base transceiver stations of the ground network system.

25. A timing unit according to claim 22, wherein the timing unit is positioned in a base transceiver station or a radio mast of the ground network system.

26. A timing unit according to claim 22, wherein that satellite from which the timing unit receives the strongest signal is selected to be listened to.

27. A timing unit according to claim 22, wherein those satellites, received by the timing unit, whose signal strengths exceed a set threshold value are selected to be listened to.

28. A timing unit according to claim 22, wherein those satellites, received by the timing unit, whose signal strengths exceed a set threshold value during the whole of the 24 hours are selected to be listened to.

29. A timing unit according to claim 22, wherein a control command determines which satellites the timing unit will not listen to.

30. A timing unit according to claim 22, wherein a control command determines which satellites the timing unit will listen to.