Method and Apparatus for Neighbor Cell Synchronization

• US 20080233988A1
• Filed: 10/18/2007
• Published: 09/25/2008
• Est. Priority Date: 03/19/2007
• Status: Active Grant

• Current Assignee: VIA Technologies Incorporated (VIA Technologies)
• Original Assignee: VIA Technologies Incorporated (VIA Technologies)
• Inventors: Wu, Yan, Yang, Shuai, Han, Teng, Cheng, Xiaoming
• Granted Patent: US 7,929,983 B2
• Time in Patent Office: Days
• US Class Current: 455/515
• CPC Class Codes: H04W 56/00 Synchronisation arrangements

Abstract

The present invention is directed to a neighbor cell synchronization method for a mobile communication unit. The method includes selecting a neighbor cell according to a scheduling mechanism; determining a synchronization window according to a communicating mode of the mobile communication unit; and searching or decoding specific logic channels within the synchronization window. The present invention also provides an apparatus for performing the method.

Claims

1. A neighbor cell synchronization method for a mobile communication unit, the method comprising the steps of:

determining if the mobile communication unit lies in a first predetermined communicating mode feasible to perform neighbor cell synchronization by using a specific wide synchronization window, wherein the specific wide synchronization window covers a plurality of contiguous frames; and

searching a neighbor cell'"'"'s specific logic channel within the specific wide synchronization window.

2. The method of claim 1, wherein the first predetermined communicating mode is a non-idle mode involving a Standalone Dedicated Control Channel (SDCCH) and the plurality of contiguous frames are selected from the group consisting of:

frames 0 to 20, frames 61 to 81, frames 74 to 94, frames 78 to 98, frames 82 to 101 and frame 0, frames 86 to 101 and frames 0 to 4, frames 41 to 61, frames 45 to 65, frames 49 to 69, and frames 53 to 73.

3. The method of claim 1, further comprising following steps:

determining if the mobile communication unit lies in a second predetermined communicating mode feasible to perform neighbor cell synchronization by using a specific narrow synchronization window, wherein the specific narrow synchronization window covers a whole range of a specific frame, a first portion of a previous frame of the specific frame and a second portion of a next frame of the specific frame; and

searching the neighbor cell'"'"'s specific logic channel within the specific narrow synchronization window.

4. The method of claim 3, wherein the first predetermined communicating mode is idle mode and the second predetermined communicating mode is talk mode.

5. The method of claim 4, wherein the first portion and the second portion are both between 312 Q-bits and 625 Q-bits.

6. The method of claim 4, wherein the sum of the lengths of the first and second portions plus the specific frame is at least 5625 Q-bits or 9 time slots.

7. The method of claim 3, further comprising following scheduling steps:

initializing a counter to a first predetermined value, the counter being assigned to correspond to a specific neighbor cell;

altering the counter by a specific value when any neighbor cell other than the specific neighbor cell is selected for synchronization;

examining the counter to determine whether the specific neighbor cell can be selected, wherein the specific neighbor cell can be selected only when the counter equals the first predetermined value; and

setting the counter to a second predetermined value when the specific neighbor cell is selected for synchronization.

8. A mobile communication unit, which comprises a processing module for neighbor cell synchronization, the processing module comprising:

a first determining unit, configured to determine that if the mobile communication unit lies in a first predetermined communicating mode feasible to perform neighbor cell synchronization by using a specific narrow synchronization window which covers a whole range of a specific frame, a first portion of a previous frame of the specific frame and a second portion of a next frame of the specific frame; and

a narrow searching unit, configured to search a neighbor cell'"'"'s specific logic channel within the specific narrow synchronization window.

9. The mobile communication unit of claim 8, wherein the first portion and the second portion are both between 312 Q-bits and 625 Q-bits.

10. The mobile communication unit of claim 8, wherein the sum of the lengths of the first and second portions plus the specific frame is at least 5625 Q-bits or 9 time slots.

11. The mobile communication unit of claim 8, wherein the processing module further comprising a neighbor cell selection unit configured to perform following steps to select a specific neighbor cell for synchronization:

initializing a counter to a first predetermined value, the counter being assigned to correspond to the specific neighbor cell;

altering the counter by a specific value when any neighbor cell other than the specific neighbor cell is selected for synchronization;

examining the counter to determine whether the specific neighbor cell can be selected, wherein the specific neighbor cell can be selected only when the counter equals the first predetermined value; and

setting the counter to a second predetermined value when the specific neighbor cell is selected for synchronization.

12. The mobile communication unit of claim 11, wherein the processing module further comprises:

a second determining module, configured to determine that if the mobile communication unit lies in a second predetermined communicating mode feasible to perform neighbor cell synchronization by using a specific wide synchronization window which covers a plurality of contiguous frames; and

a wide searching unit, configured to search the neighbor cell'"'"'s specific logic channel within the specific wide synchronization window.

13. The mobile communication unit of claim 12, wherein the first predetermined communicating mode is idle mode and the second predetermined communicating mode is idle mode.

14. The mobile communication unit of claim 12, wherein the second predetermined communicating mode is a non-idle mode involving a Standalone Dedicated Control Channel (SDCCH) and the plurality of contiguous frames are selected from the group consisting of:

frames 0 to 20, frames 61 to 81, frames 74 to 94, frames 78 to 98, frames 82 to 101 and frame 0, frames 86 to 101 and frames 0 to 4, frames 41 to 61, frames 45 to 65, frames 49 to 69, and frames 53 to 73.

15. A neighbor cell synchronization method for a mobile communication unit, comprising following scheduling steps:

initializing a counter to a first predetermined value, the counter being assigned to correspond to a specific neighbor cell;

altering the counter by a specific value when any neighbor cell other than the specific neighbor cell is selected for synchronization;

examining the counter to determine whether the specific neighbor cell can be selected, wherein the specific neighbor cell can be selected only when the counter equals the first predetermined value; and

setting the counter to a second predetermined value when the specific neighbor cell is selected for synchronization.

16. The method of claim 15, further comprising following steps:

determining if the mobile communication unit lies in a first predetermined communicating mode feasible to perform neighbor cell synchronization by using a specific wide synchronization window, wherein the specific wide synchronization window covers a plurality of contiguous frames; and

searching or decoding a neighbor cell'"'"'s specific logic channel within the specific wide synchronization window.

17. The method of claim 16, wherein the first predetermined communicating mode is a non-idle mode involving a Standalone Dedicated Control Channel (SDCCH) and the plurality of contiguous frames are selected from the group consisting of:

frames 0 to 20, frames 61 to 81, frames 74 to 94, frames 78 to 98, frames 82 to 101 and frame 0, frames 86 to 101 and frames 0 to 4, frames 41 to 61, frames 45 to 65, frames 49 to 69, and frames 53 to 73.

18. The method of claim 16, further comprising following steps:

determining if the mobile communication unit lies in a second predetermined communicating mode feasible to perform neighbor cell synchronization by using a specific narrow synchronization window, wherein the specific narrow synchronization window covers a whole range of a specific frame, a first portion of a previous frame of the specific frame and a second portion of a next frame of the specific frame; and

searching or decoding the neighbor cell'"'"'s specific logic channel within the specific narrow synchronization window.

19. The method of claim 18, wherein the first predetermined communicating mode is idle mode and the second predetermined communicating mode is talk mode.

20. The method of claim 18, wherein the first portion and the second portion are both between 312 Q-bits and 625 Q-bits.

21. The method of claim 18, wherein the sum of the lengths of the first and second portions plus the specific frame is at least 5625 Q-bits or 9 time slots.