FAST CELL SEARCH

• US 20090131037A1
• Filed: 01/10/2008
• Published: 05/21/2009
• Est. Priority Date: 01/10/2007
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Luo, Tao, Malladi, Durga Prasad, Kim, Byoung-Hoon
• Granted Patent: US 8,634,403 B2
• Time in Patent Office: Days
• US Class Current: 455/422.100
• CPC Class Codes: H04J 11/0069 Cell search, i.e. determining cell identity [cell-ID] design of multiplexing codes H04J13/00; processing access restriction or access information H04W48/16; discovery of network devices for network data management H04W8/005; sounding signals for channel estimation H04L25/0226; structure of reference signals in multicarrier modulation systems H04L27/2613; frame, time or carrier synchronisation in multicarrier modulation systems H04L27/2655
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04L 27/2655 Synchronisation arrangements
• CPC Class Codes: H04L 27/2675 Pilot or known symbols
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information

Abstract

Systems and methodologies are described that facilitate searches for a cell in a wireless communication environment. A mobile device can employ a searcher that can detect timing information respectively associated with PSCs and cells to determine the cell with the highest correlation. The searcher can detect SSCs, which can include detecting associated phase information, to determine the SSC with the highest correlation, CP length, and/or other information to facilitate identifying a desired cell having the strongest signal to establish communication between the mobile device and the desired cell. PSCs respectively associated with cells can have different positions in the symbol sequences, and SSCs can respectively be phase shifted at different angles to facilitate detection and identification of a cell(s), where a PSC can be utilized as a phase reference by the associated SSC.

Claims

1. A method that facilitates a multi-stage cell search, comprising:

detecting timing information related to primary synchronization channels (PSCs); and

identifying a cell based in part on phase information associated with a secondary synchronization channel (SSC).

2. The method of claim 1, comprising:

employing a jointly time dithered primary synchronization channel/secondary synchronization channel (PSC/SSC) that conveys network context information; and

ensuring that the PSC does not have a single frequency network (SFN) artifact in a synchronous system.

3. The method of claim 1, comprising fixing the relative time distance between two consecutive PSCs.

4. The method of claim 3, comprising fixing the relative time distance between the two consecutive PSCs regardless of cyclic prefix (CP) length.

6. The method of claim 1, comprising:

determining correlation values respectively associated with PSCs;

determining correlation values respectively associated with SSCs;

determining CP length; and

selecting the cell based in part on the determined correlation values.

7. The method of claim 1, comprising detecting and identifying which secondary synchronization channel (SSC) sequence has been transmitted from a particular cell to determine a hypotheses associated with the cell, and identification of the cell.

8. The method of claim 4, comprising searching for a base station where a cyclic prefix (CP) can be detected blindly.

9. The method of claim 2 wherein an additional phase shift of e^jkθ

is applied to SSCs, where k=0, 1, 2, . . . , M−

1, and θ

=2π

/M, wherein M relates to number of different phases that can be employed.

10. The method of claim 9, comprising applying a different phase shift to SSCs in each different base station in a network.

11. The method of claim 10, comprising applying a phase shift to an SSC, wherein a phase angle for the phase shift is based in part on a PSC sequence.

12. The method of claim 2, wherein a first SSC and a second SSC have different combinations of phase shift.

13. The method of claim 2, wherein a first SSC and a second SSC have same phase shift.

14. The method of claim 13, comprising determining number of antennas associated with a base station 102 as a function of unique mapping between number of phases and number of antennas used by the base station.

15. The method of claim 14, wherein at least three groups (α

, β

, γ

) are represented by using a combination of SSC order in a radio frame and phase modulation on top of SSCs.

16. The method of claim 2, comprising using phase shift information associated with an SSC to facilitate determining location of an associated PSC in a symbol sequence.

17. The method of claim 16, comprising perform timing detection based in part on the detected PSC.

34. An electronic device configured to execute the method of claim 1.

35. The electronic device of claim 34, configured to execute the method of claim 2.

5. The method of clam 1, wherein an SSC uses Chu sequences with different bases or different cyclic shifts.

18. A computer readable medium having stored thereon computer executable instructions for carrying out the following acts:

detecting timing information related to primary synchronization channels (PSCs); and

identifying a cell based in part on phase information associated with a secondary synchronization channel (SSC).

19. The computer readable medium of claim 18, comprising computer executable instructions for carrying out the following acts:

employing a jointly time dithered primary synchronization channel/secondary synchronization channel (PSC/SSC) that conveys network context information; and

ensuring that the PSC does not have a single frequency network (SFN) artifact in a synchrounous system.

20. The computer readable medium of claim 18, comprising computer executable instructions for carrying out the following act:

fixing the relative time distance between two consecutive PSCs.

21. The computer readable medium of claim 20, comprising computer executable instructions for carrying out the following act:

fixing the relative time distance between the two consecutive PSCs regardless of cyclic prefix (CP) length.

22. The computer readable medium of claim 18, comprising computer executable instructions for carrying out the following acts:

determining correlation values respectively associated with PSCs;

determining correlation values respectively associated with SSCs;

determining CP length; and

selecting the cell based in part on the determined correlation values.

23. The computer readable medium of claim 18, comprising computer executable instructions for carrying out the following act:

detecting and identifying which secondary synchronization channel (SSC) sequence has been transmitted from a particular cell to determine a hypotheses associated with the cell, and identification of the cell.

24. The computer readable medium of claim 21, comprising computer executable instructions for carrying out the following act:

searching for a base station where a cyclic prefix (CP) can be detected blindly.

25. The computer readable medium of claim 19, comprising computer executable instructions for carrying out the following act:

using phase shift information associated with an SSC to facilitate determining location of an associated PSC in a symbol sequence.

26. The computer readable medium of claim 18, comprising computer executable instructions for carrying out the following act:

perform timing detection based in part on the detected PSC.

27. An apparatus operable in wireless communication system, the apparatus comprising:

means for detecting timing information related to primary synchronization channels (PSCs); and

means for identifying a cell based in part on phase information associated with a secondary synchronization channel (SSC).

28. The apparatus of claim 27, comprising:

means for employing a jointly time dithered primary synchronization channel/secondary synchronization channel (PSC/SSC) that conveys network context information; and

means for ensuring that the PSC does not have a single frequency network (SFN) artifact in a synchronous system.

29. The apparatus of claim 27, comprising means for fixing relative time distance between two consecutive PSCs.

30. The apparatus of claim 29, comprising means for fixing the relative time distance between the two consecutive PSCs regardless of cyclic prefix (CP) length.

31. The apparatus of claim 27, comprising:

means for determining correlation values respectively associated with PSCs;

means for determining correlation values respectively associated with SSCs;

means for determining CP length; and

means for selecting the cell based in part on the determined correlation values.

32. The apparatus of claim 27, comprising means for detecting and identifying which secondary synchronization channel (SSC) sequence has been transmitted from a particular cell to determine a hypotheses associated with the cell, and identification of the cell.

33. The apparatus of claim 30, comprising means for searching for a base station where a cyclic prefix (CP) can be detected blindly.

36. An apparatus operable in a wireless communication system, the apparatus comprising:

a processor, configured to;

detect timing information related to primary synchronization channels (PSCs); and

identify a cell based in part on phase information associated with a secondary synchronization channel (SSC); and

a memory coupled to the processor for storing data.

37. The apparatus of claim 36, the processor configured to:

employ a jointly time dithered primary synchronization channel/secondary synchronization channel (PSC/SSC) that conveys network context information; and

ensure that the PSC does not have a single frequency network (SFN) artifact in a synchrounous system.

38. The apparatus of claim 36, the processor configured to fix relative time distance between two consecutive PSCs.

39. The apparatus of claim 38, the processor configured to fix the relative time distance between the two consecutive PSCs regardless of cyclic prefix (CP) length.

40. The apparatus of claim 36, the processor configured to:

determine correlation values respectively associated with PSCs;

determine correlation values respectively associated with SSCs;

determine CP length; and

select the cell based in part on the determined correlation values.

41. The apparatus of claim 36, the processor configured to detect and identify which secondary synchronization channel (SSC) sequence has been transmitted from a particular cell to determine a hypotheses associated with the cell, and identification of the cell.

42. The apparatus of claim 39, the processor configured to search for a base station where a cyclic prefix (CP) can be detected blindly.