Method of synchronizing broadcast parameters to support autonomous soft handoff by mobile stations

• US 20050096055A1
• Filed: 11/04/2004
• Published: 05/05/2005
• Est. Priority Date: 11/05/2003
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Balasubramanian, Srinivasan, Colban, Erik, Khan, Irfan
• Granted Patent: US 7,346,352 B2
• Time in Patent Office: Days
• US Class Current: 455/442
• CPC Class Codes: H04L 12/189 in combination with wireless systems selective distribution or broadcast in wireless communication networks H04W4/06
• CPC Class Codes: H04W 36/0007 for multicast or broadcast services, e.g. MBMS multicast or broadcast application services H04W4/06; resource management for broadcast services H04W72/30; connection management for selective distribution or broadcast H04W76/40
• CPC Class Codes: H04W 36/06 Reselecting a communication resource in the serving access point
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection
• CPC Class Codes: H04W 72/30 Resource management for broadcast services

Abstract

A method of coordinating broadcast parameter settings enables autonomous soft handoff by a mobile station. Any base station can initiate a broadcast parameter coordination process. The initiating base station assumes the role of an arbitrator and is responsible for determining the broadcast parameters. The broadcast parameter coordination process does not require any intervention or involvement by the PDSN or any signaling with the mobile station, except to inform the mobile station of the soft handoff sectors after the broadcast parameter coordination process is completed. The list of soft handoff sectors may be sent to the mobile station in a common overhead message.

Claims

1. A method of coordinating broadcast parameters between base stations to facilitate autonomous soft handoff by a mobile station, the method comprising:

detecting a broadcast parameter coordination event,

negotiating, responsive to said broadcast parameter coordination event, with one or more neighbor base stations over a sidehaul link to determine a set of common broadcast parameter settings and a set of soft handoff sectors for a designated broadcast stream.

2. The method of claim 1 further comprising sending said mobile station a list of said soft handoff sectors committed to the soft handoff for the designated broadcast stream.

3. The method of claim 1 wherein negotiating a set of common broadcast parameter settings and a set of soft handoff sectors committed to a soft handoff for a designated broadcast stream comprises:

sending a broadcast parameter coordination request message over a sidehaul link from a first base station to one or more neighbor base stations;

receiving a broadcast parameter coordination response message from one or more of the neighbor base stations over said sidehaul link, said broadcast parameter coordination response message from each neighbor base station containing a sector list identifying sectors that the neighbor base station will commit to a soft handoff for the designated broadcast stream;

determining negotiated broadcast parameter settings and soft handoff sectors at said first base station based on said broadcast parameter coordination response messages from the neighbor base stations; and

sending a broadcast parameter commit message from the first base station to one or more of the neighbor base stations over the sidehaul link, the broadcast parameter commit message containing the negotiated set of common broadcast parameter settings and a sector list identifying the soft handoff sectors committed to a soft handoff using the common set of broadcast parameter settings.

4. The method of claim 3 wherein the broadcast parameter coordination request message includes a sector list identifying sectors that the first base station will commit to include a soft handoff.

5. The method of claim 3 wherein said broadcast parameter coordination response message includes proposed broadcast parameter settings for a designated broadcast stream.

6. The method of claim 5 wherein said broadcast parameter coordination response message from each neighbor base station contains an alternate set of broadcast parameter settings if the neighbor base station is unable to commit to the proposed broadcast parameter settings contained in the broadcast parameter coordination request message.

7. The method of claim 3 wherein the first base station selects the common set of broadcast parameter settings based on the on said broadcast parameter coordination response messages from the neighbor base stations.

8. The method of claim 3 wherein negotiating a set of common broadcast parameter settings and a set of soft handoff sectors committed to a soft handoff for a designated broadcast stream comprises:

receiving a broadcast parameter coordination request message over a sidehaul link at a first base station from a second base station;

sending a broadcast parameter coordination response message over said sidehaul link to said first base station, said broadcast parameter coordination response message containing a sector list identifying sectors that the first base station will commit to a soft handoff for the designated broadcast stream; and

receiving a broadcast parameter commit message from the second base station, the broadcast parameter commit message containing the negotiated common set of broadcast parameter settings and a sector list identifying soft handoff sectors committed to a soft handoff using the common set of broadcast parameter settings.

9. The method of claim 8 wherein the broadcast parameter coordination request message includes a sector list identifying sectors that the first base station will commit to a soft handoff.

10. The method of claim 8 wherein the broadcast parameter request message includes proposed broadcast parameter settings for a designated broadcast stream.

11. The method of claim 10 wherein the broadcast parameter response message contains an alternate set of broadcast parameter settings if the first base station is unable to commit to the proposed broadcast parameter settings in the broadcast parameter coordination request message.

12. The method of claim 3 wherein negotiating a set of common broadcast parameter settings and a set of soft handoff sectors committed to a soft handoff for a designated broadcast stream comprises:

sending from a first base station a broadcast parameter coordination request message over a sidehaul link to a designated master base station that determines the common set of broadcast parameter settings for a group of sectors in a soft handoff region,

receiving at the first base station a broadcast parameter coordination response message from the master base station over said sidehaul link, said broadcast parameter coordination response message containing the common set of broadcast parameter settings for the designated broadcast stream; and

sending a broadcast parameter commit message from the first base station to the master base station over the sidehaul link, the broadcast parameter commit message including a sector list identifying sectors committed by the first base station to the soft handoff using the common set of broadcast parameter settings.

13. The method of claim 12 wherein the broadcast parameter coordination request message includes proposed broadcast parameter settings for a designated broadcast stream.

14. The method of claim 12 wherein the broadcast parameter coordination request message includes a list of sectors that the first base station will commit to a soft handoff for the designated broadcast stream.

15. The method of claim 12 wherein the broadcast parameter commit message includes an action time indicating when the common set of broadcast parameters will be effective.

16. The method of claim 12 wherein the broadcast parameter coordination response message includes a sector list identifying one or more sectors committed to a soft handoff for the designated broadcast stream.

17. The method of claim 3 wherein negotiating a set of common broadcast parameter settings and a set of soft handoff sectors committed to a soft handoff for a designated broadcast stream comprises:

receiving at a master base station a broadcast parameter coordination request message over a sidehaul link from a first base station,

determining broadcast parameters for the designated broadcast stream at the master base station;

sending a broadcast parameter coordination response message from the master base stations over said sidehaul link to said first base station, said broadcast parameter coordination response message containing the common set of broadcast parameter settings for the designated broadcast stream; and

receiving at the master base station a broadcast parameter commit message over the sidehaul link from the first base station to commit one or more sectors of the first base station to a soft handoff using the common set of broadcast parameter settings.

18. The method of claim 17 wherein the broadcast parameter coordination request message includes a list of sectors that the first base station will commit to a soft handoff for the designated broadcast stream.

19. The method of claim 18 wherein the broadcast parameter coordination request message includes proposed broadcast parameter settings for a designated broadcast stream.

20. The method of claim 19 wherein the master base station determines the common set of broadcast parameter settings based on the proposed broadcast parameter settings in the broadcast parameter coordination request message.

21. The method of claim 17 wherein the broadcast parameter coordination response message includes a sector list identifying one or more sectors committed to a soft handoff for the designated broadcast stream.

22. The method of claim 17 wherein the broadcast parameter coordination response message includes an action time indicating when the broadcast parameters will be effective

23. The method of claim 1 further wherein the broadcast parameter coordination event comprises receipt of a registration request message from a mobile station.

24. The method of claim 1 further wherein the broadcast parameter coordination event comprises a periodic trigger.

25. The method of claim 1 further wherein the broadcast parameter coordination event comprises receipt of a synchronization request message from a mobile station.

26. The method of claim 1 wherein the broadcast parameter coordination event comprises a change of conditions that dictate a need to change the broadcast parameters of the broadcast stream.

27. The method of claim 1 wherein said broadcast parameters include at least one of a frequency, long code mask, framing parameter, encryption, time synchronization parameter, coding parameter, frame offset, and power offset.

28. The method of claim 27 wherein the broadcast parameters include at least one time synchronization parameter for synchronizing transmission of said broadcast stream in the selected soft handoff sectors.

29. The method of claim 28 wherein the time synchronization parameters include a frame transmission start time for a selected frame.

30. The method of claim 29 wherein the time synchronization parameters include a start position for the selected frame.

31. The method of claim 28 wherein the time synchronization parameters include a time offset used to compute a frame transmission start time for the first broadcast frame including a part of the data packet.

32. The method of claim 28 wherein the time synchronization parameters further include a minimum and a maximum packet latency time.

33. A base station including a base station controller configured to support autonomous soft handoff by a mobile station receiving a broadcast stream, the base station controller configured to:

detect a broadcast parameter coordination event,

negotiate, responsive to said broadcast parameter coordination event, with one or more neighbor base stations over a sidehaul link to determine a set of common broadcast parameter settings and a set of soft handoff sectors for a designated broadcast stream.

34. The base station of claim 33 wherein the base station controller is further configure to transmit a list of said soft handoff sectors committed to the soft handoff for the designated broadcast stream to the mobile station.

35. The base station of claim 33 wherein base station controller negotiates a set of common broadcast parameter settings and a set of soft handoff sectors for a designated broadcast stream by:

sending a broadcast parameter coordination request message over a sidehaul link to one or more neighbor base stations;

receiving a broadcast parameter coordination response message from one or more of the neighbor base stations over said sidehaul link, said broadcast parameter coordination response message from each neighbor base station containing a sector list identifying sectors that the neighbor base station will commit to a soft handoff for the designated broadcast stream;

determining the common set of broadcast parameter settings and soft handoff sectors at said first base station based on said broadcast parameter coordination response messages from the neighbor base stations; and

sending a broadcast parameter commit message to one or more of the neighbor base stations over the sidehaul link, the broadcast parameter commit message containing the negotiated set of common broadcast parameter settings and a sector list identifying the soft handoff sectors committed to the soft handoff using the common set of broadcast parameter settings.

36. The method of claim 35 wherein the broadcast parameter coordination request message includes a sector list identifying sectors that the first base station will commit to the soft handoff.

37. The base station of claim 35 wherein said broadcast parameter coordination request message includes proposed broadcast parameter settings for a designated broadcast stream.

38. The base station of claim 37 wherein said broadcast parameter coordination response message from each neighbor base station contains an alternate set of broadcast parameter settings if the neighbor base station is unable to commit to the proposed broadcast parameter settings contained in the broadcast parameter coordination request message.

39. The base station of claim 35 wherein the base station selects the common set of broadcast parameter settings based on the on said broadcast parameter coordination response messages from the neighbor base stations.

40. The base station of claim 33 wherein base station controller negotiates a common set of broadcast parameter settings and soft handoff sectors and a set of soft handoff sectors for a designated broadcast stream by:

receiving a broadcast parameter coordination request message over a sidehaul link from a neighbor base station;

sending a broadcast parameter coordination response message to the neighbor base station over said sidehaul link, said broadcast parameter coordination response message including a sector list identifying sectors that the base station will commit to a soft handoff; and

receiving a broadcast parameter commit message from the neighbor base over the sidehaul link, the broadcast parameter commit message including the negotiated common set of broadcast parameter settings and a sector list indicating the soft handoff sectors committed to the soft handoff using the common set of broadcast parameter settings.

41. The base station of claim 40 wherein the broadcast parameter coordination request message includes a sector list identifying sectors that the base station will commit to a soft handoff for a designated broadcast stream.

42. The base station of claim 40 wherein the broadcast parameter coordination request message includes proposed broadcast parameter settings for a designated broadcast stream;

43. The base station of claim 42 wherein the broadcast parameter coordination response message includes an alternate set of broadcast parameter settings if the base station is unable to commit to the proposed broadcast parameter settings contained in the broadcast parameter coordination request message.

44. The base station of claim 33 wherein base station controller negotiates a set of common broadcast parameter settings and a set of soft handoff sectors for a designated broadcast stream by:

sending a broadcast parameter coordination request message over a sidehaul link to a designated master base station that determines the common set of broadcast parameter settings for a group of sectors in a soft handoff region,

receiving a broadcast parameter coordination response message from the master base station over said sidehaul link, said broadcast parameter coordination response message containing the common set of broadcast parameter settings for the designated broadcast stream; and

sending a broadcast parameter commit message to the master base station over the sidehaul link to commit one or more sectors to the soft handoff.

45. The base station of claim 44 wherein the broadcast parameter coordination request message includes proposed broadcast parameter settings for the designated broadcast stream.

46. The base station of claim 44 wherein the broadcast parameter coordination request message includes a list of sectors that the first base station will commit to a soft handoff for the designated broadcast stream.

47. The base station of claim 44 wherein the broadcast parameter coordination response message includes an action time indicating when the common set of broadcast parameters will be effective.

48. The base station of claim 44 wherein the broadcast parameter coordination response message includes a sector list identifying one or more sectors committed to the soft handoff using the common set of broadcast parameters.

49. The base station of claim 44 wherein the broadcast parameter commit message includes a sector list identifying sectors committed by the first base station to the soft handoff using the common set of broadcast parameter settings.

50. The base station of claim 33 wherein base station controller negotiates a set of common broadcast parameter settings and a set of soft handoff sectors for a designated broadcast stream by:

receiving a broadcast parameter coordination request message over a sidehaul link from a first base station,

determining broadcast parameters for the designated broadcast stream;

sending a broadcast parameter coordination response message over said sidehaul link to said first base station, said broadcast parameter coordination response message containing the common set of broadcast parameter settings for the designated broadcast stream; and

receiving a broadcast parameter commit message over the sidehaul link from the first base station committing one or more sectors of the first base station to a soft handoff using the common set of broadcast parameter settings.

51. The base station of claim 50 wherein the broadcast parameter coordination request message includes a list of sectors that the first base station will commit to a soft handoff for the designated broadcast stream.

52. The base station of claim 50 wherein the broadcast parameter coordination request message includes proposed broadcast parameter settings for the designated broadcast stream.

53. The base station of claim 52 wherein the base station controller determines the set of common broadcast parameter settings and soft handoff sectors based on the proposed broadcast parameter settings in the broadcast parameter coordination request message

54. The base station of claim 50 wherein the broadcast parameter coordination response message includes an action time indicating when the broadcast parameters will be effective

55. The base station claim 50 wherein the broadcast parameter coordination commit message includes a sector list identifying sectors that the first base station commits to the soft handoff.

56. The base station of claim 50 wherein the broadcast parameter coordination response message includes a sector list identifying one or more soft handoff sectors committed to the soft handoff for the designated broadcast stream.