METHOD AND APPARATUS FOR ADAPTIVE HANDOVER

• US 20090143093A1
• Filed: 11/26/2008
• Published: 06/04/2009
• Est. Priority Date: 11/29/2007
• Status: Abandoned Application

• Current Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Original Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Inventors: Terry, Stephen E., Wang, Peter S., Somasundaram, Shankar, Olvera-Hernandez, Ulises, Mukherjee, Rajat P.
• Application Number:
  US12/324,057
• Publication Number:
  US 20090143093A1
• Time in Patent Office: Days
• US Class Current: 455/525
• CPC Class Codes: H04W 36/32 by location or mobility data, e.g. speed data
• CPC Class Codes: H04W 36/324 by mobility data, e.g. speed data
• CPC Class Codes: H04W 64/006 with additional information processing, e.g. for direction or speed determination

Abstract

A method and apparatus for adaptive handover includes receiving a time to trigger (TTT) for a first mobility state. A scaling factor is received for a second mobility state. The TTT for the second mobility state is determined by scaling the first mobility state with the scaling factor for the second mobility state.

Claims

1. A method for adaptive handover, comprising:

receiving a time to trigger (TTT) for a first mobility state;

receiving a scaling factor for a second mobility state; and

determining the TTT for the second mobility state by scaling the first mobility state with the scaling factor for the second mobility state.

2. The method of claim 1, further comprising receiving a scaling factor for a third mobility state and determining the TTT for the third mobility state by scaling the first mobility state with the scaling factor for the third mobility state.

3. The method of claim 1 wherein the first mobility state is a low mobility state and the second mobility state is a medium or high mobility state.

4. The method of claim 1 wherein the scaling factor is in the range of zero (0) to one (1).

5. The method of claim 4 wherein the scaling factor is incremented in one-tenth increments.

6. A method for adaptive handover, comprising:

tracking a number of cells for which a handover is performed; and

counting new handovers to determine a mobility speed.

7. The method of claim 6 wherein a new handover includes a handover to or from a cell that a handover has not already previously been performed.

8. The method of claim 6, further comprising tracking a last connected cell and not counting a handover to the last connected cell as a new handover.

9. The method of claim 6, further comprising counting new handovers during a predefined timing interval.

10. The method of claim 9 wherein a cell to which the WTRU was previously connected is counted as a new handover when the handover is performed outside of the predefined timing interval.

11. A wireless transmit/receive unit (WTRU), comprising:

a receiver;

a transmitter; and

a processor in communication with the receiver and the transmitter, the processor configured to receive a time to trigger (TTT) for a first mobility state, receive a scaling factor for a second mobility state, and determine the TTT for the second mobility state by scaling the first mobility state with the scaling factor for the second mobility state.

12. The WTRU of claim 11 wherein the processor is further configured to receive a scaling factor for a third mobility state and determine the TTT for the third mobility state by scaling the first mobility state with the scaling factor for the third mobility state.

13. The WTRU of claim 11 wherein the first mobility state is a low mobility state and the second mobility state is a medium or high mobility state.

14. The WTRU of claim 11 wherein the scaling factor is in the range of zero (0) to one (1).

15. The WTRU of claim 14 wherein the scaling factor is incremented in one-tenth increments.

16. A wireless transmit/receive unit (WTRU), comprising:

a receiver;

a transmitter; and

a processor in communication with the receiver and the transmitter, the processor configured to track a number of cells for which a handover is performed, and count new handovers to determine a mobility speed.

17. The WTRU of claim 16 wherein a new handover includes a handover to or from a cell that a handover has not already previously been performed.

18. The WTRU of claim 16 wherein the processor is further configured to track a last connected cell and not count a handover to the last connected cell as a new handover.

19. The WTRU of claim 16 wherein the processor is further configured to count new handovers during a predefined timing interval.

20. The WTRU of claim 19 wherein the processor is further configured to count a cell to which the WTRU was previously connected as a new handover when the handover is performed outside of the predefined timing interval.