Systems and Methods for Tracking Power Peaks of a Signal

• US 20100124936A1
• Filed: 11/20/2008
• Published: 05/20/2010
• Est. Priority Date: 11/20/2008
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: FLOSER, Erling, HUSS, Fredrik, SKARBY, Ulf
• Granted Patent: US 8,055,278 B2
• Time in Patent Office: Days
• US Class Current: 455/456.500
• CPC Class Codes: H04W 56/004 compensating for timing error of reception due to propagation delay
• CPC Class Codes: H04W 60/00 Affiliation to network, e.g. registration; Terminating affiliation with the network, e.g. de-registration
• CPC Class Codes: H04W 84/047 using dedicated repeater stations

Abstract

In one aspect, the invention provides a method for tracking a mobile terminal. In some embodiments, this method includes the following steps: receiving a signal transmitted from the mobile terminal; searching a primary search area for a signal associated with the mobile terminal; searching a secondary search area for a signal associated with the mobile terminal, wherein the secondary search area is larger than the primary search area; determining the strength of a signal associated with the mobile terminal that was found by searching the secondary search area; and determining whether the primary search area should be modified based on the determined strength of the signal that was found by searching the secondary search area.

Claims

1. A method for tracking a mobile terminal, comprising:

receiving a signal transmitted from the mobile terminal;

searching a primary search area for a signal associated with the mobile terminal;

searching a secondary search area for a signal associated with the mobile terminal, wherein the secondary search area is larger than the primary search area;

determining the strength of a signal associated with the mobile terminal that was found by searching the secondary search area; and

determining whether the primary search area should be modified based on the determined strength of the signal that was found by searching the secondary search area.

2. The method of claim 1, further comprising modifying the primary search area in response to a determination that the strength of the signal that was found by searching the secondary search area exceeds a threshold.

3. The method of claim 2, further comprising modifying the primary search area in response to a determination that the strength of the signal that was found by searching the secondary search area exceeds the strength of a signal associated with the mobile terminal that was found by searching the primary search area.

4. The method of claim 3, wherein the step of modifying the primary search area comprises altering the primary search area so that the primary search area includes the location where the signal associated with the mobile terminal was found in the secondary search area.

5. The method of claim 4, wherein the step of altering the primary search area does not change the size of the primary search area.

6. The method of claim 2, wherein the step of modifying the primary search area comprises increasing the size of the primary search area.

7. The method of claim 6, wherein the size of the primary search area is increased so that the new primary search area includes the location where the signal associated with the mobile terminal was found in the secondary search area and the location where a signal associated with the mobile terminal was found in the old primary search area.

8. The method of claim 2, wherein the step of modifying the primary search area comprises creating a second primary search area.

9. The method of claim 8, further comprising continuously searching, for some period of time, the first and second primary search areas for a signal associated with the mobile terminal, wherein the second primary search area is smaller in size than the secondary search area but includes the location where the signal associated with the mobile terminal was found in the secondary search area.

10. The method of claim 1, further comprising:

sending a timing alignment value to the mobile terminal in response to a determination that the strength of the signal that was found by searching the secondary search area exceeds a threshold, wherein the timing alignment value corresponds to a delay associated with that signal.

11. The method of claim 1, wherein the secondary search area is searched less frequently than the primary search area.

12. A base station, comprising:

a receiver for receiving signals transmitted from a terminal;

a terminal tracking module configured to search a primary search area for a signal associated with the terminal;

a secondary searching module configured to search a secondary search area for a signal associated with the terminal, wherein the secondary search area is larger than the primary search area;

a signal strength determining module configured to determine the strength of a signal associated with the terminal that was found by searching the secondary search area; and

a data processing module configured to determine whether the primary search area should be modified based on a determined strength of the signal that was found by searching the secondary search area.

13. The base station of claim 12, wherein the terminal tracking module is further configured to modify the primary search area in response to receiving information indicating that the strength of the signal that was found by searching the secondary search area exceeds a threshold.

14. The base station of claim 13, wherein the threshold is equal to the strength of a signal associated with the terminal that was found by searching the primary search area.

15. The base station of claim 13, wherein the terminal tracking module is configured to modify the primary search in response to receiving said information by altering the primary search area so that the primary search area includes the location where the signal associated with the terminal was found in the secondary search area.

16. The base station of claim 15, wherein the terminal tracking module is configured such that the altering of the primary search area does not change the size of the primary search area.

17. The base station of any one of claim 13, wherein the terminal tracking module is configured to modify the primary search in response to receiving said information by increasing the size of the primary search area.

18. The base station of claim 17, wherein the terminal tracking module is configured to increase the size of the primary search area so that the new primary search area includes the location where the signal associated with the terminal was found in the secondary search area and the location where a signal associated with the terminal was found in the old primary search area.

19. The base station of claim 13, wherein the terminal tracking module is configured to modify the primary search in response to receiving said information by creating a second primary search area.

20. The base station of claim 19, wherein the terminal tracking module is configured to continuously search, for some period of time, the first and second primary search areas for a signal associated with the terminal, wherein the second primary search area is smaller in size than the secondary search area but includes the location where the signal associated with the terminal was found in the secondary search area.

21. The base station of claim 12, further comprising:

a timing module configured to send a timing alignment value to the terminal in response to a determination that the strength of the signal that was found by searching the secondary search area exceeds a threshold, wherein the timing alignment value corresponds to a delay associated with that signal.

22. The base station of claim 12, wherein the secondary searching module is configured to search the secondary search area less frequently than the tracking module is configured to search the primary search area.