Methods for determining registration at a satellite communications system and related user terminals and systems

• US 6,418,314 B2
• Filed: 05/01/1998
• Issued: 07/09/2002
• Est. Priority Date: 05/01/1998
• Status: Expired due to Term

• Current Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Lindvall, Hakan, Kolev, Javor
• Primary Examiner(s): Urban, Edward F.
• Assistant Examiner(s): SMITH, SHEILA B
• Application Number:
  US09/071,319
• Publication Number:
  US 20010014605A1
• Time in Patent Office: 1,530 Days
• Field of Search: 455/436, 455/456, 455/13.1, 455/13.2, 455/435, 455/427, 455/12.1, 455/405, 455/430, 342/357
• US Class Current: 455/435.1
• CPC Class Codes: H04B 7/18545 Arrangements for managing station mobility, i.e. for station registration or localisation

Abstract

Methods of registering a user terminal at a satellite communications system including a plurality of satellite spot beam transceivers, wherein each of the satellite spot beam transceivers defines a respective spot beam. The current spot beam registration information is transmitted from the user terminal to the satellite communications system. Updated spot beam registration information is determined for the user terminal at the satellite communications system based on the current spot beam registration information received from the user terminal. Updated spot beam registration information is transmitted from the satellite communications system to the user terminal. The user terminal updates the current spot beam registration information for the user terminal using the updated spot beam registration information received from the satellite communications system. Related systems and user terminals are also discussed.

Claims

1. A method of registering a user terminal with a satellite communications system including a plurality of satellite spot beam transceivers wherein each of the satellite spot beam transceivers defines a respective spot beam, said method comprising the steps of:

transmitting current spot beam registration information from the user terminal to the satellite communications system, wherein the current spot beam registration information identifies at least one spot beam via which the satellite communication system currently pages the user terminal;

determining updated spot beam registration information for the user terminal at the satellite communications system based on the current spot beam registration information received from the user terminal and based on a periodic oscillation associated with alternating spot beam coverage of the user terminal;

transmitting said updated spot beam registration information from the satellite communications system to the user terminal, wherein the updated spot beam registration information is different than the current spot beam registration information and identifies at least one spot beam via which the satellite communication system currently pages the user terminal; and

updating the current spot beam registration information for the user terminal using the updated spot beam registration information received from the satellite communications system.

2. The method of claim 1 wherein the current spot beam registration information comprises a current servicing spot beam and a previous servicing spot beam wherein the current servicing spot beam currently provides service to the user terminal and wherein the previous spot beam provided service to the user terminal immediately prior to the current servicing spot beam.

10. The method of claim 2 wherein said step of updating comprises the step of storing the updated spot beam registration information received from the satellite communications system in the user terminal.

11. The method of claim 2 wherein said step of transmitting the current spot beam registration information is triggered upon detection of new servicing spot beam other than the current servicing spot beam and the previous servicing spot beam.

13. The method of claim 1 wherein said step of transmitting current spot beam registration information is triggered by communication between the user terminal and the satellite communications system.

3. A method of registering a user terminal with a satellite communications system including a plurality of satellite spot beam transceivers wherein each of the satellite spot beam transceivers defines a respective spot beam, said method comprising the steps of:

transmitting current spot beam registration information from the user terminal to the satellite communications system, wherein the current spot beam registration information comprises a current servicing spot beam and a previous servicing spot beam wherein the current servicing spot beam currently provides service to the user terminal and wherein the previous spot beam provided service to the user terminal immediately prior to the current servicing spot beam and wherein the current spot beam registration information further comprises a user terminal timer value wherein the user terminal timer value provides a duration of service provided by the current servicing spot beam within a spot beam pair wherein the current servicing spot beam and the previous servicing spot beam define the spot beam pair;

determining updated spot beam registration information for the user terminal at the satellite communications system based on the current spot beam registration information received from the user terminal;

transmitting said updated spot beam registration information from the satellite communications system to the user terminal; and

updating the current spot beam registration information for the user terminal using the updated spot beam registration information received from the satellite communications system.

4. The method of claim 3 wherein the updated spot beam registration information comprises information indicating that the user terminal is registered with a single spot beam when the current spot beam and the previous spot beam define a spot beam pair and the user terminal time value exceeds or is equal to a period of oscillation associated with the current and previous servicing spot beams.

5. The method of claim 3 wherein the updated spot beam registration information comprises information indicating that the user terminal is registered with a spot beam pair when the current servicing spot beam and the previous servicing spot beam define a spot beam pair and the user terminal time value does not exceed the period of oscillation associated with the current and previous servicing spot beams.

6. The method of claim 3 wherein said step of updating further comprises the steps of invalidating the previous spot beam in the user terminal and clearing a user terminal timer when the updated spot beam registration information received from the communication satellite system indicates that the user terminal is registered with a single spot beam.

7. A method of registering a user terminal with a satellite communications system including a plurality of satellite spot beam transceivers wherein each of the satellite spot beam transceivers defines a respective spot beam said method comprising the steps of:

transmitting current spot beam registration information from the user terminal to the satellite communications system, wherein the current spot beam registration information comprises a current servicing spot beam and a previous servicing spot beam wherein the current servicing spot beam currently provides service to the user terminal and wherein the previous spot beam provided service to the user terminal immediately prior to the current servicing spot beam,

determining updated spot beam registration information for the user terminal at the satellite communications system based on the current spot beam registration information received from the user terminal;

transmitting said updated spot beam registration information from the satellite communications system to the user terminal; and

updating the current spot beam registration information for the user terminal using the updated spot beam registration information received from the satellite communications system, wherein the updated spot beam registration information comprises information indicating that the user, terminal is registered with a single spot beam when the current servicing spot beam and the previous servicing spot beam do not define a spot beam pair wherein the spot beam pair is defined by two adjacent spot beams.

8. The method of claim 7 wherein spot beam pair identifiers are stored in a database wherein the spot beam pair identifiers provide an indication of whether the current servicing spot beam and the previous servicing spot beam define the spot beam pair.

9. The method of claim 8 wherein the database further comprises a home location register and a visiting location register wherein the home location register stores identifiers of subscribers and wherein the visiting location register stores identifiers of affiliated subscribers.

12. A method of registering a user terminal with a satellite communications system including a plurality of satellite spot beam transceivers wherein each of the satellite spot beam transceivers defines a respective spot beam, said method comprising the steps of:

transmitting current spot beam registration information from the user terminal to the satellite communications system;

determining updated spot beam registration information for the user terminal at the satellite communications system based on the current spot beam registration information received from the user terminal;

transmitting said updated spot beam registration information from the satellite communications system to the user terminal;

updating the current spot beam registration information for the user terminal using the updated spot beam registration information received from the satellite communications system;

detecting a new servicing spot beam;

designating the current servicing spot beam as the previous servicing spot beam;

designating the new servicing spot beam as the current servicing spot beam; and

clearing a user terminal time value wherein the user terminal time value measures the duration of the service provided by the current servicing spot beam within a spot beam pair wherein the current spot beam and the previous spot beam form the spot beam pair.

14. A method of registering a user terminal with a satellite communications system including a plurality of satellite spot beam transceivers wherein each of the satellite spot beam transceivers defines a respective spot beam, said method comprising the steps of:

transmitting current spot beam registration information from the user terminal to the satellite communications system, wherein said step of transmitting the current spot beam registration information is triggered upon expiration of a periodic location update timer wherein the periodic location update timer measures a duration of service provided to the user terminal since a previous expiration of the periodic location update timer;

determining updated spot beam registration information for the user terminal at the satellite communications system based on the current spot beam registration information received from the user terminal;

transmitting said updated spot beam registration information from the satellite communications system to the user terminal; and

updating the current spot beam registration information for the user terminal using the updated spot beam registration information received from the satellite communications system.

15. A method of registering a user terminal with a satellite communications system including a plurality of satellite spot beam transceivers wherein each of the satellite spot beam transceivers defines a respective spot beam, said method comprising the steps of:

transmitting current spot beam registration information from the user terminal to the satellite communications system, wherein the current spot beam registration information comprises a user terminal timer value wherein the user terminal timer value provides a duration of service provided by a current servicing spot beam within a spot beam pair wherein the current servicing spot beam and a previous servicing spot beam define the spot beam pair;

determining updated spot beam registration information for the user terminal at the satellite communications system based on the current spot beam registration information received from the user terminal;

transmitting said updated spot beam registration information from the satellite communications system to the user terminal, and

updating the current spot beam registration information for the user terminal using the updated spot beam registration information received from the satellite communications system.

16. The method of claim 15 wherein the updated spot beam registration information indicates that the user terminal is registered with a single spot beam when the user terminal time value exceeds or is equal to a period of oscillation associated with the current and previous servicing spot beams.

17. The method of claim 15 wherein the updated spot beam registration information indicates that the user terminal is registered with a spot beam pair when the user terminal time value does not exceed the period of oscillation associated with the current and previous servicing spot beams.

18. A user terminal for communicating with a satellite communications system including a plurality of satellite spot beam transceivers wherein each of the satellite spot beam transceivers defines a respective spot beam, said user terminal comprising:

a transceiver which transmits and receives communications to and from the satellite communications system;

memory wherein said memory stores current spot beam registration information for the user terminal; and

a processor coupled to said transceiver and said memory wherein said processor transmits said current spot beam registration information from said memory through said transceiver to the satellite communications system, wherein the current spot beam registration information identifies at least one spot beam via which the satellite communication system currently pages the user terminal, wherein the satellite communications system determines updated spot beam registration information based on said current spot beam registration information received from the user terminal and based on a periodic oscillation associated with alternating spot beam coverage of the user terminal, wherein said processor receives said updated spot beam registration information from the satellite communications system through said transceiver, wherein the updated spot beam registration information is different than the current spot beam registration information and identifies at least one spot beam via which the satellite communication system currently pages the user terminal, and wherein said processor stores said updated spot beam registration information from the satellite communications system in said memory.

19. The user terminal of claim 18 wherein the current spot beam registration information comprises a current servicing spot beam and a previous servicing spot beam wherein the current servicing spot beam currently provides service to the user terminal and wherein the previous spot beam provided service to the user terminal immediately prior to the current servicing spot beam.

25. The user terminal of claim 19 wherein the transmission of current spot beam registration information is triggered upon detection of new servicing spot beam other than the current servicing spot beam and the previous servicing spot beam.

26. The user terminal of claim 19 wherein updating comprises storing the updated spot beam registration information received from the satellite communications system in the user terminal.

27. The user terminal of claim 18 wherein the transmission of current spot beam registration information is triggered by communication between the user terminal and the satellite communications system.

20. A user terminal for communicating with a satellite communications system including a plurality of satellite spot beam transceivers wherein each of the satellite spot beam transceivers defines a respective spot beam, said user terminal comprising:

a transceiver which transmits and receives communications to and from the satellite communications system;

memory wherein said memory stores current spot beam registration information for the user terminal; and

a processor coupled to said transceiver and said memory wherein said processor transmits said current spot beam registration information from said memory through said transceiver to the satellite communications system, wherein the satellite communications system determines updated spot beam registration information based on said current spot beam registration information received from the user terminal, wherein said processor receives said updated spot beam registration information from the satellite communications system through said transceiver, and wherein said processor stores said updated spot beam registration information from the satellite communications system in said memory, wherein the current spot beam registration information comprises a current servicing spot beam and a previous servicing spot beam wherein the current servicing spot beam currently provides service to the user terminal and wherein the previous spot beam provided service to the user terminal immediately prior to the current servicing spot beam, wherein the current spot beam registration information further comprises a user terminal timer value wherein the user terminal timer value provides a duration of service provided by the current servicing spot beam within a spot beam pair wherein the current servicing spot beam and the previous servicing spotbeam define the spot beam pair.

21. The user terminal of claim 20 wherein the updated spot beam registration information comprises information indicating that the user terminal is registered with a single spot beam when the current spot beam and the previous spot beam define a spot beam pair and the user terminal time value exceeds or is equal to a period of oscillation associated with the current and previous servicing spot beams.

22. The user terminal of claim 20 wherein the updated spot beam registration information comprises information indicating that the user terminal is registered with a spot beam pair when the current servicing spot beam and the previous servicing spot beam define a spot beam pair and the user terminal time value does not exceed the period of oscillation associated with the current and previous servicing spot beams.

23. The user terminal of claim 20 wherein updating further comprises invalidating the previous spot beam in the user terminal and clearing a user terminal timer when the updated spot beam registration information received from the communication satellite system indicates that the user terminal is registered with a single spot beam.

24. A user terminal for communicating with a satellite communications system including a plurality of satellite spot beam transceivers wherein each of the satellite spot beam transceivers defines a respective spot beam, said user terminal comprising:

a transceiver which transmits and receives communications to and from the satellite communications system;

memory wherein said memory stores current spot beam registration information for the user terminal; and

a processor coupled to said transceiver and said memory wherein said processor transmits said current spot beam registration information from said memory through said transceiver to the satellite communications system, wherein the satellite communications system determines updated spot beam registration information based on said current spot beam registration information received from the user terminal wherein said processor receives said updated spot beam registration information from the satellite communications system through said transceiver, and wherein said processor stores said updated spot beam registration information from the satellite communications system in said memory, wherein the current spot beam registration information comprises a current servicing spot beam and a previous servicing spot beam wherein the current servicing spot beam currently provides service to the user terminal and wherein the previous spot beam provided service to the user terminal immediately prior to the current servicing spot beam, wherein the updated spot beam registration information comprises information indicating that the user terminal is registered with a single spot beam when the current servicing spot beam and the previous servicing spot beam do not define a spot beam pair wherein the spot beam pair is formed by two adjacent spot beams.

28. A user terminal for communicating with a satellite communications system including a plurality of satellite spot beam transceivers wherein each of the satellite spot beam transceivers defines a respective spot beam, said user terminal comprising:

a transceiver which transmits and receives communications to and from the satellite communications system;

memory wherein said memory stores current spot beam registration information for the user terminal; and

a processor coupled to said transceiver and said memory wherein said processor transmits said current spot beam registration information from said memory through said transceiver to the satellite communications system, wherein the satellite communications system determines updated spot beam registration information based on said current spot beam registration information received from the user terminal, wherein said processor receives said updated spot beam registration information from the satellite communications system through said transceiver, and wherein said processor stores said updated spot beam registration information from the satellite communications system in said memory wherein the transmission of current spot beam registration information is triggered upon expiration of a periodic location update timer wherein the periodic location update timer measures a duration of service provided to the user terminal since a previous expiration of the periodic location update timer.

29. A user terminal for communicating with a satellite communications system including a plurality of satellite spot beam transceivers wherein each of the satellite spot beam transceivers defines a respective spot beam, said user terminal comprising:

a transceiver which transmits and receives communications to and from the satellite communications system;

memory wherein said memory stores current spot beam registration information for the user terminal; and

a processor coupled to said transceiver and said memory wherein said processor transmits said current spot beam registration information from said memory through said transceiver to the satellite communications system, wherein the satellite communications system determines updated spot beam registration information based on said current spot beam registration information received from the user terminal, wherein said processor receives said updated spot beam registration information from the satellite communications system through said transceiver, and wherein said processor stores said updated spot beam registration information from the satellite communications system in said memory, wherein said processor detects a new servicing spot beam, designates the current servicing spot beam as the previous servicing spot beam, designates the new servicing spot beam as the current servicing spot beam and clears a user terminal time value wherein the user terminal time value measures the duration of the service provided by the current servicing spot beam within a spot beam pair wherein the current spot beam and the previous spot beam form the spot beam pair.

30. A user terminal for communicating with a satellite communications system including a plurality of satellite spot beam transceivers wherein each of the satellite spot beam transceivers defines a respective spot beam, said user terminal comprising:

a transceiver which transmits and receives communications to and from the satellite communications system;

memory wherein said memory stores current spot beam registration information for the user terminal; and

a processor coupled to said transceiver and said memory wherein said processor transmits said current spot beam registration information from said memory through said transceiver to the satellite communications system, wherein the satellite communications system determines updated spot beam registration information based on said current spotbeam registration information received from the user terminal, wherein said processor receives said updated spot beam registration information from the satellite communications system through said transceiver, and wherein said processor stores said updated spot beam registration information from the satellite communications system in said memory, wherein the current spot beam registration information comprises a user terminal timer value wherein the user terminal timer value provides a duration of service provided by a current servicing spot beam within a spot beam pair wherein the current servicing spot beam and a previous servicing spot beam define the spot beam pair.

31. A satellite communications system for communicating with a user terminal, the system comprising:

a plurality of satellite spot beam transceivers wherein each of the satellite spot beam transceivers defines a respective spot beam; and

a controller coupled to said spot beam transceivers wherein said controller receives current spot beam registration information from the user terminal through one of said transceivers, wherein the current spot beam registration information identifies at least one spot beam via which the satellite communication system currently pages the user terminal, wherein said controller determines updated spot beam registration information based on said current spot beam registration information and based on a periodic oscillation associated with alternating spot beam coverage of the user terminal, and wherein said controller transmits said updated spot beam registration information to the user terminal through said transceiver so that the current spot beam registration information is updated at the user terminal using said updated spot beam registration information, wherein the updated spot beam registration information is different than the current spot beam registration information and identifies at least one spot beam via which the satellite communication system currently pages the user terminal.

32. The satellite communications system of claim 31 wherein the current spot beam registration information comprises a current servicing spot beam and a previous servicing spot beam wherein the current servicing spot beam currently provides service to the user terminal and wherein the previous spot beam provided service to the user terminal immediately prior to the current servicing spot beam.

33. A satellite communications system for communicating with a user terminal, the system comprising:

a plurality of satellite spot beam transceivers wherein each of the satellite spot beam transceivers defines a respective spot beam; and

a controller coupled to said spot beam transceivers wherein said controller receives current spot beam registration information from the user terminal through one of said transceivers, wherein said controller determines updated spot beam registration information based on said current spot beam registration information, and wherein said controller transmits said updated spot beam registration information to the user terminal through said transceiver so that the current spot beam registration information is updated at the user terminal using said updated spot beam registration information, wherein the current spot beam registration information comprises a current servicing spot beam and a previous servicing spot beam wherein the current servicing spot beam currently provides service to the user terminal and wherein the previous spot beam provided service to the user terminal immediately prior to the current servicing spot beam, wherein the current spot beam registration information further comprises a user terminal timer value wherein the user terminal timer value provides a duration of service provided by the current servicing spot beam within a spot beam pair wherein the current servicing spot beam and the previous servicing spot beam define the spot beam pair.

34. The satellite communications system of claim 33 wherein the updated spot beam registration information comprises information indicating that the user terminal is registered with a spot beam pair when the current servicing spot beam and the previous servicing spot beam define a spot beam pair and the user terminal time value does not exceed the period of oscillation associated with the current and previous servicing spot beams.

35. The satellite communications system of claim 33 wherein the updated spot beam registration information comprises information indicating that the user terminal is registered with a single spot beam when the current spot beam and the previous spot beam define a spot beam pair and the user terminal time value exceeds or is equal to a period of oscillation associated with the current and previous servicing spot beams.

37. The satellite communications system of claim 34 wherein spot beam pair identifiers are stored in a database wherein the spot beam pair identifiers provide an indication of whether the current servicing spot beam and the previous servicing spot beam define the spot beam pair.

38. The satellite communications system of claim 37 wherein the database further comprises a home location register and a visiting location register wherein the home location register stores identifiers of subscribers and wherein the visiting location register stores identifiers of affiliated subscribers.

36. A satellite communications system for communicating with a user terminal, the system comprising:

a plurality of satellite spot beam transceivers wherein each of the satellite spot beam transceivers defines a respective spot beam; and

a controller coupled to said spot beam transceivers wherein said controller receives current spot beam registration information from the user terminal through one of said transceivers, wherein said controller determines updated spot beam registration information based on said current spot beam registration information, and wherein said controller transmits said updated spot beam registration information to the user terminal through said transceiver so that the current spot beam registration information is updated at the user terminal using said updated spot beam registration information, wherein the current spot beam registration information comprises a current servicing spot beam and a previous servicing spot beam wherein the current servicing spot beam currently provides service to the user terminal and wherein the previous spot beam provided service to the user terminal immediately prior to the current servicing spot beam, wherein the updated spot beam registration information comprises information indicating that the user terminal is registered with a single spot beam when the current servicing spot beam and the previous servicing spot beam do not define a spot beam pair wherein the spot beam pair is formed by two adjacent spot beams.

39. A satellite communications system for communicating with a user terminal, the system comprising:

a plurality of satellite spot beam transceivers wherein each of the satellite spot beam transceivers defines a respective spot beam; and

a controller coupled to said spot beam transceivers wherein said controller receives current spot beam registration information from the user terminal through one of said transceivers, wherein said controller determines updated spot beam registration information based on said current spot beam registration information, and wherein said controller transmits said updated spot beam registration information to the user terminal through said transceiver so that the current spot beam registration information is updated at the user terminal using said updated spot beam registration information, wherein the updated spot beam registration information indicates that the user terminal is registered with a single spot beam when the user terminal time value exceeds or is equal to a period of oscillation associated with the current and previous servicing spot beams.

40. The satellite communications system of claim 39 wherein the updated spot beam registration information indicates that the user terminal is registered with a spot beam pair when the user terminal time value does not exceed the period of oscillation associated with the current and previous servicing spot beams.

41. A method of registering a user terminal with a satellite communications system including a plurality of satellite spot beam transceivers wherein each of the satellite spot beam transceivers defines a respective spot beam, said method comprising the steps of:

receiving current spot beam registration information from the user terminal at the satellite communications system, wherein the current spot beam registration information identifies at least one spot beam via which the satellite communication system currently pages the user terminal;

determining updated spot beam registration information for the user terminal at the satellite communications system based on the current spot beam registration information received from the user terminal and based on a periodic oscillation associated with alternating spot beam coverage of the user terminal; and

transmitting said updated spot beam registration information from the satellite communications system to the user terminal, wherein the updated spot beam registration information is different than the current spot beam registration information and identifies at least one spot beam via which the satellite communication system currently pages the user terminal.

42. The method of claim 41 wherein the current spot beam registration information comprises a current servicing spot beam and a previous servicing spot beam wherein the current servicing spot beam currently provides service to the user terminal and wherein the previous spot beam provided service to the user terminal immediately prior to the current servicing spot beam.

43. A method of registering a user terminal with a satellite communications system including a plurality of satellite spot beam transceivers wherein each of the satellite spot beam transceivers defines a respective spot beam, said method comprising the steps of:

receiving current spot beam registration information from the user terminal at the satellite communications system, wherein the current spot beam registration information comprises a current servicing spot beam and a previous servicing spot beam wherein the current servicing spot beam currently provides service to the user terminal and wherein the previous spot beam provided service to the user terminal immediately prior to the current servicing spot beam, wherein the current spot beam registration information further comprises a user terminal timer value wherein the user terminal timer value provides a duration of service provided by the current servicing spot beam within a spot beam pair wherein the current servicing spot beam and the previous servicing spot beam define the spot beam pair;

determining updated spot beam registration information for the user terminal at the satellite communications system based on the current spot beam registration information received from the user terminal; and

transmitting said updated spot beam registration information from the satellite communications system to the user terminal.

44. A method of registering a user terminal with a satellite communications system including a plurality of satellite spot beam transceivers wherein each of the satellite spot beam transceivers defines a respective spot beam, said method comprising the steps of:

transmitting current spot beam registration information from the user terminal to the satellite communications system, wherein the current spot beam registration information identifies at least one spot beam via which the satellite communication system currently pages the user terminal;

receiving updated spot beam registration information from the satellite communications system at the user terminal, wherein the updated spot beam registration information is different than the current spot beam registration information and identifies at least one spot beam via which the satellite communication system currently pages the user terminal; and

updating the current spot beam registration information for the user terminal using the updated spot beam registration information received from the satellite communications system based on a periodic oscillation associated with alternating spot beam coverage of the user terminal.

45. The method of claim 44 wherein the current spot beam registration information comprises a current servicing spot beam and a previous servicing spot beam wherein the current servicing spot beam currently provides service to the user terminal and wherein the previous spot beam provided service to the user terminal immediately prior to the current servicing spot beam.

46. A method of registering a user terminal with a satellite communications system including a plurality of satellite spot beam transceivers wherein each of the satellite spot beam transceivers defines a respective spot beam, said method comprising the steps of:

transmitting current spot beam registration information from the user terminal to the satellite communications system, wherein the current spot beam registration information comprises a current servicing spot beam and a previous servicing spot beam wherein the current servicing spot beam currently provides service to the user terminal and wherein the previous spot beam provided service to the user terminal immediately prior to the current servicing spot beam, wherein the current spot beam registration information further comprises a user terminal timer value wherein the user terminal timer value provides a duration of service provided by the current servicing spot beam within a spot beam pair wherein the current servicing spot beam and the previous servicing spot beam define the spot beam pair;

receiving updated spot beam registration information from the satellite communications system at the user terminal; and

updating the current spot beam registration information for the user terminal using the updated spot beam registration information received from the satellite communications system.