Balancing paging load and tracking area updates

• US 8,989,744 B2
• Filed: 06/24/2013
• Issued: 03/24/2015
• Est. Priority Date: 03/08/2007
• Status: Active Grant

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Wang, Peter S., Mukherjee, Rajat P., Wang, Jin, Somasundaram, Shankar, Miller, James M., Olvera-Hernandez, Ulises
• Primary Examiner(s): FARAGALLA, MICHAEL A
• Application Number:
  US13/925,116
• Publication Number:
  US 20130288682A1
• Time in Patent Office: 638 Days
• Field of Search: 455/436, 455/456.1
• US Class Current: 455/436
• CPC Class Codes: H04W 36/04 Reselecting a cell layer in multi-layered cells
• CPC Class Codes: H04W 36/22 for handling the traffic
• 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 36/36 by user or terminal equipment
• CPC Class Codes: H04W 36/362 Conditional handover
• CPC Class Codes: H04W 4/08 User group management
• CPC Class Codes: H04W 68/00 User notification, e.g. alerting and paging, for incoming communication, change of service or the like
• CPC Class Codes: H04W 76/38 triggered by timers
• CPC Class Codes: H04W 8/186 Processing of subscriber group data
• CPC Class Codes: H04W 8/205 Transfer to or from user equipment or user record carrier
• CPC Class Codes: H04W 84/042 Public Land Mobile systems, e.g. cellular systems
• CPC Class Codes: H04W 84/105 PBS [Private Base Station] network H04W84/12 - H04W84/16 take precedence

Abstract

A method for assigning a tracking area (TA) is disclosed. A mobility state of a wireless transmit/receive unit (WTRU) is determined and the TA is assigned based on the determined mobility state. Also disclosed is a method for accessing a closed subscriber group (CSG) TA.A CSG TA identifier is received at a WTRU and is stored. A CSG TA broadcast is received and the broadcast CSG TA is accessed if an identifier of the broadcast CSG TA matches the stored CSG TA identifier. Also disclosed is a method for changing a mobility state of a WTRU. A current mobility state of the WTRU is determined and a predetermined metric of the WTRU is examined. The predetermined metric is evaluated to determine if the metric has crossed a threshold and the mobility state is changed based on the evaluated metric.

Claims

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

a processor configured to;

determine a measured number of cell reselections;

set a timer length to a first value on a condition that the measured number of cell reselections is less than a first threshold;

set the timer length to a second value on a condition that the measured number of cell reselections is greater than the first threshold but less than a second threshold; and

set the timer length to a third value on a condition that the measured number of cell reselections is greater than the second threshold.

2. The WTRU of claim 1 wherein the processor is further configured to set a mobility state based at least in part on the measured number of cell reselections.

3. The WTRU of claim 2 wherein the processor is further configured to:

set the mobility state to a low mobility state on the condition that the measured number of cell reselections is less than the first threshold;

set the mobility state to a medium mobility state on the condition that the measured number of cell reselections is more than the first threshold but less than the second threshold; and

set the mobility state to a high mobility state on the condition that the measured number of cell reselections is more than the second threshold.

4. The WTRU of claim 1 wherein the processor is further configured to adjust the timer length to achieve an optimum paging efficiency.

5. The WTRU of claim 1 wherein the processor is further configured to scale the timer length based on the measured number of cell reselections.

6. The WTRU of claim 2, further comprising:

a positioning circuitry configured to determine at least a first position of the WTRU and a second position of the WTRU; and

the processor further configured to set the mobility state based at least in part on the first position and the second position.

7. The WTRU of claim 6, further comprising:

a transmitter configured to transmit an indication of the first position and the second position to at least a first base station.

8. The WTRU of claim 6, further comprising:

the processor further configured to determine a speed of the WTRU based on the first position and the second position; and

a transmitter configured to transmit an indication of the speed of the WTRU to a base station.

9. The WTRU of claim 2, further comprising:

a receiver configured to receive an indication of the mobility state from a base station.

19. The WTRU of claim 1 further comprising a Universal Subscriber Identity Module (USIM), wherein the processor is further configured to read information from the USIM.

20. The WTRU of claim 19, wherein the USIM is configured to store an allowed list associated with at least one of a macro cell, a small cell, a femto-cell, a Home Node B (HNB) cell, a Home e-Node B (HeNB), and a Closed Subscriber Group (CSG) cell.

21. The WTRU of claim 20, wherein the processor is further configured to perform a cell reselection to a cell indicated in the allowed list.

22. The WTRU of claim 21, wherein the USIM resides on a Universal Integrated Circuit Card (UICC) and the processor is operatively coupled to the UICC.

23. The WTRU of claim 22 further comprising a transceiver operatively coupled to the processor and configured to wirelessly communicate with the cell to perform the cell reselection.

10. A method performed in a wireless transmit/receive unit (WTRU), the method comprising:

determining a measured number of cell reselections;

setting a timer length to a first value on a condition that the measured number of cell reselections is less than a first threshold;

setting the timer length to a second value on a condition that the measured number of cell reselections is greater than a first threshold but less than a second threshold; and

setting the timer length to a third value on a condition that the measured number of cell reselections is greater than the second threshold.

11. The method of claim 10 further comprising setting a mobility state based at least in part on the measured number of cell reselections.

12. The method of claim 11 further comprising:

setting the mobility state to a low mobility state on the condition that the measured number of cell reselections is less than the first threshold;

setting the mobility state to a medium mobility state on the condition that the measured number of cell reselections is more than the first threshold but less than the second threshold; and

setting the mobility state to a high mobility state on the condition that the measured number of cell reselections is more than the second threshold.

13. The method of claim 10 further comprising adjusting the timer length to achieve an optimum paging efficiency.

14. The method of claim 10 wherein the setting the timer length further includes scaling the timer length based on the measured number of cell reselections.

15. The method of claim 11, further comprising:

determining at least a first position of the WTRU and a second position of the WTRU; and

setting the mobility state based at least in part on the first position and the second position.

16. The method of claim 15, further comprising transmitting an indication of the first position and the second position to at least a first base station.

17. The method of claim 15, further comprising:

determining a speed of the WTRU based on the first position and the second position; and

transmitting an indication of the speed of the WTRU to a base station.

18. The method of claim 11, further comprising receiving an indication of the mobility state from a base station.

24. The method of claim 10, further comprising storing, in a Universal Subscriber Identity Module (USIM), an allowed list associated with at least one of a macro cell, a small cell, a femto-cell, a Home Node B (HNB) cell, a Home e-Node B (HeNB), and a Closed Subscriber Group (CSG) cell.

25. The method of claim 24, further comprising performing a cell reselection to a cell indicated in the allowed list.

26. The method of claim 25, wherein the USIM resides on a Universal Integrated Circuit Card (UICC).

27. The method of claim 26, further comprising wirelessly communicating with the cell to perform the cell reselection.