CHANNEL HANDOFF METHODS IN WIRELESS BROADCAST SYSTEMS

• US 20080020768A1
• Filed: 07/25/2007
• Published: 01/24/2008
• Est. Priority Date: 09/27/2005
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Krishnamoorthi, Raghuraman, Li, Linbo, Ling, Fuyun, Mantravadi, Ashok
• Granted Patent: US 9,554,319 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04W 36/28 involving a plurality of connections, e.g. multi-call or multi-bearer connections
• CPC Class Codes: H04W 36/302 due to low signal strength
• CPC Class Codes: H04W 72/542 using measured or perceived quality

Abstract

Systems and methodologies are described that facilitate monitoring RF channels in a wireless communication environment to determine whether one or more channels comprise a forward-link-only (FLO) signal. A receiver can receive a first RF channel with a FLO signal and can monitor other RF channels for FLO signals. Upon a determination that a monitored RF channel comprises a FLO signal, the receiver can switch between the first RF channel and the monitored RF channel, employing information on current MLC decoding status, to facilitate providing seamless reception of the FLO signal, which can be superframe synchronized between RF channels. FLO signal detection can be performed using one or more of a wide-area identification channel energy detection protocol and a wide-area overhead information symbol decoding error detection protocol.

Claims

1. A method of monitoring and switching between radio frequencies at an access terminal in a wireless communication environment, comprising:

measuring a signal quality for a current channel;

determining whether the measured signal quality is above a predetermined threshold value;

monitoring a signal quality of at least one neighbor channel; and

generating a handoff flag based at least in part on the signal quality of the current channel and the at least one neighbor channel.

2. The method of claim 1, wherein the signal quality includes at least one of a received signal strength indicator (RSSI), signal to interference plus noise ratio or cyclic prefix (CP) correlation.

3. The method of claim 1, further comprising disabling RF monitoring if a measured RSSI is above the predetermined threshold value.

4. The method of claim 1, further comprising enabling RF monitoring if the measured RSSI is less than or equal to the predetermined threshold value.

5. The method of claim 1, further comprising determining whether one or more MediaFLO logical channel (MLC) segments failure has occurred.

6. The method of claim 5, further comprising executing an RF monitoring subroutine if an MLC failure has not occurred.

7. The method of claim 6, further comprising updating an RF lookup table and executing a handoff flag generation subroutine if no MLC failure has been detected.

8. The method of claim 7, further comprising determining whether a handoff flag, which indicates that an associated access terminal is to be handed off to a new RF, is present.

9. The method of claim 8, further comprising handing the access terminal off to at least one of a destination RF, a destination wide-area identity, and a destination local-area identity.

10. The method of claim 5, further comprising initiating timeout logic upon an MLC failure.

11. The method of claim 10, further comprising enabling RF monitoring and obtaining OIS information for the one or more MLC segments.

12. The method of claim 11, further comprising initiating an RF monitoring subroutine.

13. The method of claim 12, further comprising updating an RF lookup table and executing a handoff flag generation subroutine if one or more MLC failures is detected.

14. The method of claim 13, further comprising determining whether a handoff flag, which indicates that an associated access terminal is to be handed off to a new RF, is present.

15. The method of claim 14, further comprising handing the access terminal off to at least one of a destination RF, a destination wide-area identity, and a destination local-area identity.

16. The method of claim 1, further comprising determining whether an OIS failure has occurred.

17. The method of claim 16, further comprising initiating a background RF monitoring protocol if an OIS failure is not detected.

18. The method of claim 16, further comprising implementing OIS failure timeout logic if an OIS failure is detected.

19. The method of claim 18, further comprising updating an RF lookup table with information related to RFs that are monitored.

20. The method of claim 19, further comprising handing off an access terminal from a current RF to an optimal RF having a highest RSSI value according to the RF lookup table.

21. An apparatus that facilitates switching between radio frequencies (RFs) at an access terminal in a wireless communication environment, comprising:

a receiver that monitors at least one neighboring RF and analyzes an RSSI there for;

a memory that stores information related to RSSI and identity information for a current RF and the at least one neighboring RF; and

a processor, coupled to the memory, that switches between the current RF channel and the at least one neighboring RF channel.

22. The apparatus of claim 21, wherein the receiver determines whether the measured RSSI is above a predetermined threshold value;

23. The apparatus of claim 22, further comprising determining whether an overhead information symbol (OIS) failure has occurred, and initiating a reacquisition protocol if an OIS failure has occurred.

24. The apparatus of claim 23, wherein the receiver determines whether one or more multi-level coded (MLC) segments failure has occurred.

25. The apparatus of claim 24, wherein the receiver executes an RF monitoring subroutine if an MLC failure has not occurred.

26. The apparatus of claim 24, wherein the processor updates an RF lookup table and executes a handoff flag generation subroutine if one or more MLC failures is detected.

27. The apparatus of claim 26, wherein the processor switches to at least one of a destination RF, a destination wide-area identity, and a destination local-area identity, which are identified by the handoff flag.

28. A wireless communication apparatus, comprising:

means for measuring a signal quality for a current channel;

means for determining whether the measured signal quality is above a predetermined threshold value;

means for monitoring a signal quality of at least one neighbor channel; and

means for generating a handoff flag based at least in part on the signal quality of the current channel and the at least one neighbor channel.

29. The apparatus of claim 28, wherein the signal quality includes at least one of a received signal strength indicator (RSSI), signal to interference plus noise ratio or cyclic prefix (CP) correlation.

30. The apparatus of claim 28, further comprising means for disabling RF monitoring if a measured RSSI is above the predetermined threshold value and enabling RF monitoring if the measured RSSI is less than or equal to the predetermined threshold value.

31. The apparatus of claim 28, further comprising means for determining whether one or more multi-level coded (MLC) segments failure has occurred.

32. The apparatus of claim 31, further comprising means for executing an “

MLC successful”

RF monitoring subroutine if an MLC failure has not occurred.

33. The apparatus of claim 32, further comprising means for updating an RF lookup table and generating a handoff flag that indicates an imminent handoff of the access terminal to a new RF if one or more MLC failures is detected.

34. The apparatus of claim 33, further comprising means for handing the access terminal off to at least one of a destination RF, a destination wide-area identity, and a destination local-area identity, which is identified by the handoff flag.

35. The apparatus of claim 31, further comprising means for initiating timeout logic upon an MLC failure, means for enabling RF monitoring, and means for obtaining OIS information for the one or more MLC segments.

36. The apparatus of claim 35, further comprising means for initiating an RF monitoring subroutine, means for updating an RF lookup table, and means for generating a handoff flag, which indicates that an associated access terminal is to be handed off to a new RF, if one or more MLC failures is detected.

37. The apparatus of claim 28 further comprising means for handing the access terminal off to at least one of a destination RF, a destination wide-area identity, and a destination local-area identity, which is indicated by the handoff flag.

38. The apparatus of claim 28, further comprising means for determining whether an OIS failure has occurred.

39. The apparatus of claim 38, further comprising means for initiating a background RF monitoring protocol if an OIS failure has not occurred.

40. The apparatus of claim 38, further comprising means for implementing OIS failure timeout logic if an OIS failure has occurred.

41. The apparatus of claim 40, further comprising means for updating an RF lookup table with information related to the monitored RFs, and means for handing off an access terminal from a current RF to an optimal RF having a highest RSSI value according to the RF lookup table.

42. A computer-readable medium having a computer program comprising computer-executable instructions for:

measuring a signal quality for a current channel;

determining whether the measured signal quality is above a predetermined threshold value;

monitoring a signal quality of at least one neighbor channel; and

generating a handoff flag based at least in part on the signal quality of the current channel and the at least one neighbor channel.

43. The computer-readable medium of claim 42, wherein the signal quality includes at least one of a received signal strength indicator (RSSI), signal to interference plus noise ratio or cyclic prefix (CP) correlation.

44. The computer-readable medium of claim 42, further comprising instructions for disabling RF monitoring if a measured RSSI is above the predetermined threshold value and enabling RF monitoring if the measured RSSI is less than or equal to the predetermined threshold value.

45. The computer-readable medium of claim 42, further comprising instructions for determining whether one or more multi-level coded (MLC) segments failure has occurred.

46. The computer-readable medium of claim 45, further comprising instructions for executing an “

MLC successful”

RF monitoring subroutine if an MLC failure has not occurred.

47. The computer-readable medium of claim 46, further comprising instructions for updating an RF lookup table and generating a handoff flag that indicates an imminent handoff of the access terminal to a new RF if one or more MLC failures is detected.

48. The computer-readable medium of claim 47, further comprising instructions for handing the access terminal off to at least one of a destination RF, a destination wide-area identity, and a destination local-area identity, which are identified by the handoff flag.

49. The computer-readable medium of claim 45, further comprising instructions for initiating timeout logic upon an MLC failure, for enabling RF monitoring, and for obtaining OIS information for the one or more MLC segments.

50. The computer-readable medium of claim 49, further comprising instructions for initiating an RF monitoring subroutine, for updating an RF lookup table, and for generating a handoff flag, which indicates that an associated access terminal is to be handed off to a new RF, if one or more MLC failures is detected.

51. The computer-readable medium of claim 50, further comprising instructions for handing the access terminal off to at least one of a destination RF, a destination wide-area identity, and a destination local-area identity, which are indicated by the handoff flag.

52. The computer-readable medium of claim 42, further comprising instructions for determining whether an OIS failure has occurred.

53. The computer-readable medium of claim 52, further comprising instructions for initiating a background RF monitoring protocol if an OIS failure has not occurred.

54. The computer-readable medium of claim 52, further comprising instructions for implementing OIS failure timeout logic if an OIS failure has occurred.

55. The computer-readable medium of claim 54, further comprising instructions for updating an RF lookup table with information related to the monitored RFs, and for handing off an access terminal from a current RF to an optimal RF having a highest RSSI value according to the RF lookup table.

56. A processor that executes instructions for increasing throughput in a wireless communication environment, the instructions comprising:

measuring a signal quality for a current channel;

determining whether the measured signal quality is above a predetermined threshold value;

monitoring a signal quality of at least one neighbor channel; and

generating a handoff flag based at least in part on a decoder error rate or the signal quality of the current channel and the at least one neighbor channel.

57. The processor of claim 56, wherein the signal quality includes at least one of a received signal strength indicator (RSSI), signal to interference plus noise ratio or cyclic prefix (CP) correlation.

58. The processor of claim 56, the instructions further comprising disabling RF monitoring if a measured RSSI is above the predetermined threshold value and enabling RF monitoring if the measured RSSI is less than or equal to the predetermined threshold value.

59. The processor of claim 56, the instructions further comprising determining whether one or more multi-level coded (MLC) segments failure has occurred.

60. The processor of claim 59, the instructions further comprising executing an “

MLC successful”

RF monitoring subroutine if an MLC failure has not occurred.

61. The processor of claim 60, the instructions further comprising updating an RF lookup table and generating a handoff flag that indicates an imminent handoff of the access terminal to a new RF if one or more MLC failures is detected.

62. The processor of claim 61, the instructions further comprising handing the access terminal off to at least one of a destination RF, a destination wide-area identity, and a destination local-area identity, which is identified by the handoff flag.

63. The processor of claim 59, the instructions further comprising initiating timeout logic upon an MLC failure, enabling RF monitoring, and obtaining OIS information for the one or more MLC segments.

64. The processor of claim 63, the instructions further comprising initiating an RF monitoring subroutine, updating an RF lookup table, and generating a handoff flag, which indicates that an associated access terminal is to be handed off to a new RF, if one or more MLC failures is detected.

65. The processor of claim 64, the instructions further comprising handing the access terminal off to at least one of a destination RF, a destination wide-area identity, and a destination local-area identity, which are indicated by the handoff flag.

66. The processor of claim 56, the instructions further comprising determining whether an OIS failure has occurred.

67. The processor of claim 66, the instructions further comprising initiating a background RF monitoring protocol if an OIS failure has not occurred.

68. The processor of claim 66, the instructions further comprising implementing OIS failure timeout logic if an OIS failure has occurred.

69. The processor of claim 68, the instructions further comprising updating an RF lookup table with information related to the monitored RFs, and handing off an access terminal from a current RF to an optimal RF having a highest RSSI value according to the RF lookup table.