Fast cell search

• US 9,480,006 B2
• Filed: 01/20/2014
• Issued: 10/25/2016
• Est. Priority Date: 01/10/2007
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Malladi, Durga Prasad, Kim, Byoung-Hoon, Luo, Tao
• Primary Examiner(s): LIN, KENNY S
• Application Number:
  US14/159,390
• Publication Number:
  US 20140135001A1
• Time in Patent Office: 1,009 Days
• Field of Search: None
• US Class Current: 1/1
• 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 primary synchronization channels (PSCs), wherein a relative time distance between two consecutive PSCs is fixed regardless of a cyclic prefix (CP) length;

using the PSCs as a phase reference for detecting secondary synchronization channels (SSCs); and

determining a phase shift of one of the SSCs based at least in part on the phase reference.

2. The method of claim 1, further comprising identifying a cell based in part on phase information associated with the SSCs.

3. The method of claim 2, further comprising:

evaluating the phase information associated with the SSCs to identify a first cell that transmitted a strongest signal; and

establishing communication with the first cell.

4. The method of claim 1, further comprising:

determining correlation values respectively associated with the PSCs;

determining correlation values respectively associated with the SSCs; and

selecting a cell based at least in part on the correlation values.

5. The method of claim 1, further comprising:

detecting which secondary synchronization channel (SSC) sequence has been transmitted from a particular cell; and

determining a hypothesis associated with an identified cell, different from the particular cell, based at least in part on detecting the SSC from the particular cell.

6. The method of claim 1, further comprising:

utilizing phase information associated with a secondary synchronization channel (SSC) sequence to facilitate determining a location of an associated PSC in a symbol sequence.

7. The method of claim 1, further comprising:

detecting the relative time distance between two PSCs based at least in part on timing information related to the detected PSCs.

8. The method of claim 1, wherein one or more of the SSCs comprise Chu sequences with at least one of different bases or different cyclic shifts.

9. The method of claim 1, further comprising:

applying a different phase shift to SSCs in each different cell in a network.

10. The method of claim 9, wherein a first SSC and a second SSC have different combinations of phase shift.

11. The method of claim 1, wherein a first SSC and a second SSC have a same phase shift.

12. The method of claim 1, 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 a number of different phases that can be employed.

13. The method of claim 1, further comprising:

determining a number of antennas associated with a particular cell based at least in part on phase information associated with an SSC.

14. A non-transitory computer readable medium storing code for wireless communication, the code comprising instructions for:

detecting primary synchronization channels (PSCs), wherein a relative time distance between two consecutive PSCs is fixed regardless of cyclic prefix (CP) length;

using the PSCs as a phase reference for detecting secondary synchronization channels (SSCs); and

determining a phase shift of one of the SSCs based at least in part on the phase reference.

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

means for detecting primary synchronization channels (PSCs), wherein a relative time distance between two consecutive PSCs is fixed regardless of cyclic prefix (CP) length;

means for using the PSCs as a phase reference for detecting secondary synchronization channels (SSCs); and

means for determining a phase shift of one of the SSCs based at least in part on the phase reference.

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

a processor, configured to;

detect primary synchronization channels (PSCs), wherein a relative time distance between two consecutive PSCs is fixed regardless of cyclic prefix (CP) length;

use the PSCs as a phase reference for detecting secondary synchronization channels (SSCs); and

determine a phase shift of one of the SSCs based at least in part on the phase reference.

17. The apparatus of claim 16, wherein the processor is further configured to identify a cell based in part on phase information associated with the SSCs.

18. The apparatus of claim 17, wherein the processor is further configured to:

evaluate the phase information associated with the SSCs to identify a first cell that transmitted a strongest signal; and

establish communication with the first cell.

19. The apparatus of claim 16, wherein the processor is further configured to:

determine correlation values respectively associated with the PSCs;

determine correlation values respectively associated with the SSCs; and

select a cell based at least in part on the correlation values.

20. The apparatus of claim 16, wherein the processor is further configured to:

detect which secondary synchronization channel (SSC) sequence has been transmitted from a particular cell; and

determine a hypothesis associated with an identified cell, different from the particular cell, based at least in part on detecting the SSC from the particular cell.

21. The apparatus of claim 16, wherein the processor is further configured to:

utilize phase information associated with a secondary synchronization channel (SSC) sequence to facilitate determining a location of an associated PSC in a symbol sequence.

22. The apparatus of claim 16, wherein the processor is further configured to:

detect the relative time distance between two PSCs based at least in part on timing information related to the detected PSCs.

23. The apparatus of claim 16, wherein one or more of the SSCs comprise Chu sequences with at least one of different bases or different cyclic shifts.

24. The apparatus of claim 16, wherein the processor is further configured to:

apply a different phase shift to SSCs in each different cell in a network.

25. The apparatus of claim 24, wherein a first SSC and a second SSC have different combinations of phase shift.

26. The apparatus of claim 16, wherein a first SSC and a second SSC have a same phase shift.

27. The apparatus of claim 16, 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 a number of different phases that can be employed.

28. The apparatus of claim 16, wherein the processor is further configured to:

determine a number of antennas associated with a particular cell based on phase information associated with an SSC.