Methods and apparatus for interference decrease/cancellation on downlink acquisition signals

1. A method of wireless communication, comprising:

estimating a channel from a received signal using one or more channel estimation schemes;

removing a component signal, associated with a first base station, using the estimated channel from the received signal to generate a processed signal;

applying one or more false alarm reduction schemes on the processed signal, the processed signal comprising a component signal from a second base station, the component signal from the second base station being weaker than the component signal associated with the first base station; and

detecting a residual signal in the processed signal based on the applied one or more false alarm reduction schemes, the residual signal including signaling associated with the second base station,

wherein one of the one or more false alarm reduction schemes comprises verifying an existence of the second base station by:

determining that a reference signal received power in the residual signal is higher than a threshold, the reference signal received power being associated with the second station, and

confirming the existence of the second base station by performing a cyclic redundancy check of a physical broadcast channel in response to determining the reference signal received power is higher than the threshold, the physical broadcast channel being associated with the second base station.

2. The method of claim 1 , wherein the received signal comprises components from a plurality of cells.

3. The method of claim 1 , wherein the estimating further comprises:

detecting a primary synchronization signal in the received signal; and

generating a channel estimate using the primary synchronization signal.

4. The method of claim 1 , wherein the estimating further comprises:

obtaining a reference signal; and

generating a channel estimate using the reference signal.

5. The method of claim 4 , wherein the obtaining further comprises:

detecting a signal from a first cell, wherein the signal from the first cell includes the reference signal with reference signal symbols; and

obtaining the estimated channel using the reference signal symbols.

6. The method of claim 5 , wherein the reference signal symbols are included in the reference signal across multiple subframes.

7. The method of claim 5 , wherein the reference signal symbols are included in the reference signal in either a multimedia broadcast single frequency network (MBSFN) subframe or a blank subframe.

8. The method of claim 5 , wherein the obtaining the estimated channel using the reference signal symbols further comprises estimating the channel from the reference symbols in a single antenna system and combining with at least one of channel estimates from primary or secondary synchronization signals.

9. The method of claim 5 , wherein the obtaining the estimated channel using the reference signal symbols further comprises estimating the channel from the reference symbols in a multiple antenna system and combining with at least one of channel estimates from primary or secondary signals using precoding vector steering.

10. The method of claim 9 , further comprising linking a precoding vector used in the primary and secondary synchronization signals with a cell ID and a system frame number.

11. The method of claim 1 , wherein one of the one or more channel estimation schemes comprises:

decoding a first cell physical broadcast channel; and

applying the decoded first cell physical broadcast channel to primary synchronization signals and secondary synchronization signals associated with the received signal.

12. The method of claim 11 , wherein the applying further comprises multiplying the physical broadcast channel with a precoding vector to obtain a channel to apply to the primary synchronization signals and the secondary synchronization signals.

13. The method of claim 11 , further comprising linking a precoding vector used in the primary and secondary synchronization signals with a cell ID and a system frame number.

14. The method claim 1 , wherein one of the one or more false alarm reduction schemes comprises comparing a received power of the residual signal with a threshold value.

15. The method of claim 14 , wherein the threshold value comprises at least one of:

a defined threshold value;

a threshold generated from a detected strongest cell; or

a threshold generated from an average of multiple detected cells.

16. The method of claim 1 , further comprising performing automatic gain control on the residual signal.

17. The method of claim 16 , wherein the automatic gain control further comprises applying a scaling factor to the residual signal based on at least one of:

the estimated channel; or

an energy difference between the received signal and the residual signal.

18. The method of claim 1 , further comprising:

determining that the residual signal and a signal associated with the estimated channel have similar transmitted primary synchronization signals; and

storing information associated with the estimated channel and a detected timing, wherein the stored information further comprises detected primary synchronization signals.

19. The method of claim 1 ,

wherein the received signal includes a primary synchronization signal and a secondary synchronization signal for facilitating cell detection, and

wherein the estimating comprises:

detecting the secondary synchronization signal in the received signal; and

generating a channel estimate using the secondary synchronization signal.

20. The method of claim 1 ,

wherein the one of the one or more false alarm reduction schemes further comprises determining that a received power of the physical broadcast channel, associated with the second base station, is higher than another threshold; and

wherein the decoding is further performed in response to determining the physical broadcast channel received power is higher than the other threshold.

21. The method of claim 1 , wherein the one or more false alarm reduction schemes is performed for a plurality of cells.

22. An apparatus for wireless communication, comprising:

means for estimating a channel from a received signal using one or more channel estimation schemes;

means for removing a component signal, associated with a first base station, using the estimated channel from the received signal to generate a processed signal; and

means for applying one or more false alarm reduction schemes on the processed signal, the processed signal comprising a component signal from a second base station, the component signal from the second base station being weaker than the component signal associated with the first base station;

means for detecting a residual signal in the processed signal based on the applied one or more false alarm reduction schemes, the residual signal including signaling associated with the second base station,

wherein one of the one or more false alarm reduction schemes comprises verifying an existence of the second base station by:

determining that a reference signal received power in the residual signal is higher than a threshold, the reference signal received power being associated with the second base station, and

confirming the existence of the second base station by performing a cyclic redundancy check of a physical broadcast channel in response to determining the reference signal received power is higher than the threshold, the physical broadcast channel being associated with the second base station.

23. The apparatus of claim 22 , wherein the received signal comprises components from a plurality of cells.

24. The apparatus of claim 22 , wherein the means for estimating further comprises:

means for detecting a primary synchronization signal in the received signal; and

means for generating a channel estimate using the primary synchronization signal.

25. The apparatus of claim 22 , wherein the means for estimating further comprises:

means for obtaining a reference signal; and

means for generating a channel estimate using the reference signal.

26. The apparatus of claim 25 , wherein the means for obtaining further comprises:

means for detecting a signal from a first cell, wherein the signal from the first cell includes the reference signal with reference signal symbols; and

means for obtaining the estimated channel using the reference signal symbols.

27. The apparatus of claim 26 , wherein the reference signal symbols are included in the reference signal across multiple subframes.

28. The apparatus of claim 26 , wherein the reference signal symbols are included in the reference signal in either a multimedia broadcast single frequency network (MBSFN) subframe or a blank subframe.

29. The apparatus of claim 26 , wherein the means for obtaining the estimated channel using the reference signal symbols further comprises means for estimating the channel from the reference symbols in a single antenna system and means for combining with at least one of channel estimates from primary or secondary synchronization signals.

30. The apparatus of claim 26 , wherein the means for obtaining the estimated channel using the reference signal symbols further comprises means for estimating the channel from the reference symbols in a multiple antenna system and means for combining with at least one of channel estimates from primary or secondary signals using precoding vector steering.

31. The apparatus of claim 30 , further comprising means for linking a precoding vector used in the primary and secondary synchronization signals with a cell ID and a system frame number.

32. The apparatus of claim 22 , wherein the means for estimating a channel from the received signal using one or more channel estimation schemes comprises:

means for decoding a first cell physical broadcast channel; and

means for applying the decoded first cell physical broadcast channel to primary synchronization signals and secondary synchronization signals associated with the received signal.

33. The apparatus of claim 32 , wherein the means for applying further comprises means for multiplying the physical broadcast channel with a precoding vector to obtain a channel to apply to the primary synchronization signals and the secondary synchronization signals.

34. The apparatus of claim 32 , further comprising means for linking a precoding vector used in the primary and secondary synchronization signals with a cell ID and a system frame number.

35. The apparatus of claim 22 , wherein the means for applying the one or more false alarm reduction schemes comprises means for comparing a received power of the residual signal with a threshold value.

36. The apparatus of claim 35 , wherein the threshold value comprises at least one of:

a defined threshold value;

a threshold generated from a detected strongest cell; or

a threshold generated from an average of multiple detected cells.

37. The apparatus of claim 22 , further comprising means for performing automatic gain control on the residual signal.

38. The apparatus of claim 37 , wherein the means for performing automatic gain control further comprises means for applying a scaling factor to the residual signal based on at least one of:

the estimated channel; or

an energy difference between the received signal and the residual signal.

39. The apparatus of claim 22 , further comprising:

means for determining that the residual signal and a signal associated with the estimated channel have similar transmitted primary synchronization signals; and

means for storing information associated with the estimated channel and a detected timing, wherein the stored information further comprises detected primary synchronization signals.

40. The apparatus of claim 22 ,

wherein the received signal includes a primary synchronization signal and a secondary synchronization signal for facilitating cell detection, and

wherein the means for estimating comprises:

means for detecting the secondary synchronization signal in the received signal; and

means for generating a channel estimate using the secondary synchronization signal.

41. The apparatus of claim 22 , wherein the means for applying one or more false alarm reduction schemes is configured to perform the one or more false alarm reduction schemes for a plurality of cells.

42. A non-transitory computer-readable medium storing computer executable code for wireless communication, comprising code for:

estimating a channel from a received signal using one or more channel estimation schemes;

removing a component signal, associated with a first base station, using the estimated channel from the received signal to generate a processed signal;

applying one or more false alarm reduction schemes on the processed signal, the processed signal comprising a component signal from a second base station, the component signal from the second base station being weaker than the component signal associated with the first base station; and

detecting a residual signal in the processed signal based on the applied one or more false alarm reduction schemes, the residual signal including signaling associated with the second base station,

wherein one of the one or more false alarm reduction schemes comprises verifying an existence of the second base station by:

determining that a reference signal received power in the residual signal is higher than a threshold, the reference signal received power being associated with the second base station, and

confirming the existence of the second base station by performing a cyclic redundancy check of a physical broadcast channel in response to determining the reference signal received power is higher than the threshold, the physical broadcast channel being associated with the second base station.

43. The computer-readable medium of claim 42 , wherein the received signal comprises components from a plurality of cells.

44. The computer-readable medium of claim 42 , wherein the code for estimating further comprises code for:

detecting a primary synchronization signal in the received signal; and

generating a channel estimate using the primary synchronization signal.

45. The computer-readable medium of claim 42 , wherein one of the one or more channel estimation schemes comprise code for:

decoding a first cell physical broadcast channel; and

applying the decoded first cell physical broadcast channel to primary synchronization signals and secondary synchronization signals associated with the received signal.

46. The computer-readable medium of claim 42 , wherein one of the one or more false alarm reduction schemes comprises code for comparing a received power of the residual signal with a threshold value.

47. The computer-readable medium of claim 42 , wherein the non-transitory computer-readable medium further comprises code for:

determining that the residual signal and a signal associated with the estimated channel have similar transmitted primary synchronization signals; and

storing information associated with the estimated channel and a detected timing, wherein the stored information further comprises detected primary synchronization signals.

48. The computer-readable medium of claim 42 , further comprising code for performing automatic gain control on the residual signal.

49. The computer-readable medium of claim 42 ,

wherein the received signal includes a primary synchronization signal and a secondary synchronization signal for facilitating cell detection, and

wherein the code for estimating comprises code for:

detecting the secondary synchronization signal in the received signal; and

generating a channel estimate using the secondary synchronization signal.

50. The computer-readable of claim 42 , wherein the code for applying one or more false alarm reduction schemes is configured to perform the one or more false alarm reduction schemes for a plurality of cells.

51. An apparatus for wireless communication, comprising:

at least one processor; and

a memory coupled to the at least one processor, wherein the at least one processor is configured to:

estimate a channel from a received signal using one or more channel estimation schemes;

remove a component signal, associated with a first base station, using the estimated channel from the received signal to generate a processed signal;

apply one or more false alarm reduction schemes on the processed signal, the processed signal comprising a component signal from a second base station, the component signal from the second base station being weaker than the component signal associated with the first base station; and

detect a residual signal in the processed signal based on the applied one or more false alarm reduction schemes, the residual signal including signaling associated with the second base station,

wherein to apply one of the one or more false alarm reduction schemes the at least one processor is further configured to verify an existence of the second base station by:

determine that a reference signal received power in the residual signal is higher than a threshold, the reference signal received power being associated with the second base station, and

confirming the existence of the second base station by performing a cyclic redundancy check of a physical broadcast channel in response to determining the reference signal received power is higher than the threshold, the physical broadcast channel being associated with the second base station.

52. The apparatus of claim 51 , wherein the received signal comprises components from a plurality of cells.

53. The apparatus of claim 51 , wherein to estimate a channel from the received signal using one or more channel estimation schemes the at least one processor is further configured to:

detect a primary synchronization signal in the received signal; and

generate a channel estimate using the primary synchronization signal.

54. The apparatus of claim 51 , wherein to estimate a channel from the received signal using one or more channel estimation schemes, the at least one processor is further configured to:

decode a first cell physical broadcast channel; and

apply the decoded first cell physical broadcast channel to primary synchronization signals and secondary synchronization signals associated with the received signal.

55. The apparatus of claim 51 , wherein to apply one of the one or more false alarm reduction schemes the at least one processor is further configured to compare a received power of the residual signal with a threshold value.

56. The apparatus of claim 51 , wherein the at least one processor is further configured to:

determine that the residual signal and a signal associated with the estimated channel have similar transmitted primary synchronization signals; and

store information associated with the estimated channel and a detected timing, wherein the stored information further comprises detected primary synchronization signals.

57. The apparatus of claim 51 , wherein the at least one processor is further configured to perform automatic gain control on the residual signal.

58. The apparatus of claim 51 ,

wherein the received signal includes a primary synchronization signal and a secondary synchronization signal for facilitating cell detection, and

wherein to estimate a channel from the received signal using one or more channel estimation schemes the at least one processor is further configured to:

detect the secondary synchronization signal in the received signal; and

generate a channel estimate using the secondary synchronization signal.

59. The apparatus of claim 51 , wherein the at least one processor is further configured to apply one or more false alarm reduction schemes by performing the one or more false alarm reduction schemes for a plurality of cells.