RF CHANNEL SWITCHING IN BROADCAST OFDM SYSTEMS

• US 20100165851A1
• Filed: 03/11/2010
• Published: 07/01/2010
• 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 8,705,370 B2
• Time in Patent Office: Days
• US Class Current: 370/242
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information

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 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 detecting a forward link only (FLO) signal in a radio frequency (RF) in a wireless communication environment, comprising:

determining whether a monitoring condition exists; and

monitoring at least one new RF channel to determine whether a FLO signal is present therein.

2. The method of claim 1, wherein the monitoring condition is at least on of a loss-of-lock event and an application-initiated monitoring event.

3. The method of claim 1, wherein background monitoring of the at least one new RF channel is performed according to a predetermined schedule that is at least one of continuous and periodic.

4. The method of claim 1, further comprising attempting to detect a time-division multiplexed (TDM) pilot.

5. The method of claim 4, further comprising initiating a counter to zero to detect the TDM pilot.

6. The method of claim 5, further comprising incrementing the counter.

7. The method of claim 6, further comprising determining whether the TDM pilot has been detected.

8. The method of claim 7, further comprising further incrementing the counter if the TDM pilot is not detected.

9. The method of claim 7, further comprising determining whether a counter value is greater than a value associated with the TDM pilot if the TDM pilot is detected.

10. The method of claim 9, further comprising concluding that the FLO signal is not present in the new RF channel if the counter value is greater than the TDM pilot value.

11. The method of claim 9, further comprising determining whether a late-detection attempt is to be initiated if the counter value is not greater than the TDM pilot value.

12. The method of claim 11, further comprising re-incrementing the counter and attempting to detect the TDM pilot if a late-detection attempt is initiated.

13. The method of claim 11, further comprising evaluating an energy level associated with a wide area identification (WID) channel if no late-detection attempt is initiated and comparing the WID channel energy level to a predetermined threshold.

14. The method of claim 13, further comprising determining whether the WID channel energy level is greater than a predetermined threshold level.

15. The method of claim 14, further comprising concluding that the FLO signal is not present in the new RF channel if the WID channel energy level is not greater than the threshold level.

16. The method of claim 14, further comprising concluding that the FLO signal is present in the new RF channel if the WID channel energy level is greater than the threshold level.

17. The method of claim 16, further comprising permitting channel switching from a current RF channel to the new RF channel.

18. The method of claim 14, further comprising determining whether a decoding error has occurred during decoding of a wide area overhead information symbol (WOIS) if the WID energy level is greater than the threshold level.

19. The method of claim 18, further comprising concluding that the FLO signal is not present in the new RF channel if a decoding error has occurred.

20. The method of claim 18, further comprising concluding that the FLO signal is present in the new RF channel if a decoding error has not occurred.

21. The method of claim 20, further comprising permitting channel switching from a current RF channel to the new RF channel.

22. The method of claim 11, further comprising determining whether a decoding error has occurred during decoding of a WOIS if no late-detection attempt is initiated.

23. The method of claim 22, further comprising concluding that the FLO signal is not present in the new RF channel if a decoding error has occurred.

24. The method of claim 22, further comprising concluding that the FLO signal is present in the new RF channel if a decoding error has not occurred.

25. The method of claim 24, further comprising permitting channel switching from a current RF channel to the new RF channel.

26. An apparatus that facilitates detecting a forward link only (FLO) signal in a monitored radio frequency (RF) channel in a wireless communication environment, comprising:

a receiver that monitors at least one new RF channel while receiving a FLO signal over a current RF channel;

a memory that stores information related to the RF channels; and

a processor, coupled to the memory, that switches between the current RF channel and the at least one new RF channel when the at least one new RF channel is determined to comprise a duplicate of the FLO signal.

27. The apparatus of claim 26, the receiver further comprises a FLO signal monitor that detects the flow signal in the new RF channel upon at least one of a loss-of-lock event and an application-initiated FLO detection event.

28. The apparatus of claim 26, the receiver further comprises a background monitor that monitors the at least one new RF channel to determine whether a FLO signal is present therein.

29. The apparatus of claim 28, wherein the background monitor receives a list of new RF channels via a control channel.

30. The apparatus of claim 28, wherein the background monitor performs RF channel monitoring continuously.

31. The apparatus of claim 28, wherein the background monitor periodically attempts to detect a FLO signal in the at least one new RF channel at least once per superframe.

32. The apparatus of claim 26, wherein the receiver determines whether a wide area identification channel energy level is above a predetermined threshold level to determine whether the FLO signal is present in the at least one new RF channel.

33. The apparatus of claim 26, wherein the receiver determines whether a decoding error has occurred during decoding of a wide area overhead information symbol to determine whether the FLO signal is present in the at least one new RF channel.

34. A wireless communication apparatus, comprising:

means for receiving a current RF channel comprising a FLO signal;

means for monitoring a new RF channel;

means for determining whether a FLO signal is present in the new RF channel; and

means for switching between the current RF channel and the new RF channel when a FLO signal is determined to be present in the new RF channel.

35. The apparatus of claim 34, further comprising means for performing RF channel monitoring upon at least one of a loss-of-lock on a current RF channel and an application-initiated monitoring of the new RF channel.

36. The apparatus of claim 34, further comprising means for performing background monitoring of the new RF channel, wherein the new RF channel is selected from a list of available RF channels received via a control channel.

37. The apparatus of claim 34, further comprising means for evaluating a wide area identification (WID) channel energy level for the new RF channel.

38. The apparatus of claim 37, further comprising means for comparing the WID channel energy level to a threshold level to determine whether the new RF channel contains a FLO signal.

39. The apparatus of claim 34, further comprising means for determining whether a wide area information overhead symbol (WOIS) decoding error has occurred to assess whether the new RF channel comprises a FLO signal.

40. The apparatus of claim 34, wherein FLO signals on the current RF channel and the new RF channel are superframe-synchronized.

41. A computer-readable medium having stored thereon computer-executable instructions for:

receiving a first RF channel comprising a FLO signal;

monitoring at least one other RF channel;

determining whether a FLO signal is present in the at least one other RF channel; and

switching between the first RF channel and the at least one other RF channel when a FLO signal is determined to be present in the at least one other RF channel.

42. The computer-readable medium of claim 41, further comprising instructions for performing RF channel monitoring upon at least one of a loss-of-lock on a current RF channel and an application-initiated monitoring of the at least one other RF channel.

43. The computer-readable medium of claim 41, further comprising instructions for performing background monitoring of the at least one other RF channel, wherein the at least one other RF channel is selected from a list of available RF channels received via a control channel.

44. The computer-readable medium of claim 41, further comprising instructions for evaluating a wide area identification (WID) channel energy level for the at least one other RF channel.

45. The computer-readable medium of claim 44, further comprising instructions for comparing the WID channel energy level to a threshold level to determine whether at least one other RF channel contains a FLO signal.

46. The computer-readable medium of claim 41, further comprising instructions for determining whether a wide area information overhead symbol (WOIS) decoding error has occurred to assess whether the at least one other RF channel comprises a FLO signal.

47. The computer-readable medium of claim 41, wherein FLO signals on the first RF channel and the at least one other RF channel are superframe-synchronized.

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

receiving a first RF channel comprising a FLO signal;

monitoring a second RF channel;

determining whether a FLO signal is present in the second RF channel; and

switching between the first RF channel and the second RF channel when a FLO signal is determined to be present in the second RF channel.

49. The processor of claim 48, the instructions further comprising performing RF channel monitoring upon at least one of a loss-of-lock on a current RF channel and an application-initiated monitoring of a new RF channel.

50. The processor of claim 48, the instructions further comprising performing background monitoring of the second RF channel, wherein the second RF channel is selected from a list of available RF channels received via a control channel.

51. The processor of claim 48, the instructions further comprising evaluating a wide area identification (WID) channel energy level for the second RF channel.

52. The processor of claim 51, the instructions further comprising comparing the WID channel energy level to a threshold level to determine whether the second RF channel contains a FLO signal.

53. The processor of claim 48, the instructions further comprising determining whether a wide area information overhead symbol (WOIS) decoding error has occurred to assess whether the second RF channel comprises a FLO signal.

54. The processor of claim 48, wherein FLO signals on the first RF channel and the second RF channel are superframe-synchronized.