Balancing paging load and tracking area updates
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.
1. A method performed in a wireless transmit/receive unit (WTRU), the method comprising:
determining a measured number of cell reselections; and
setting a mobility state based on the measured number of cell reselections;
wherein the mobility state is set to a low mobility state when the measured number of cell reselections is less than a first threshold, the mobility state is set to a medium mobility state when the measured number of cell reselections is more than the first threshold but less than a second threshold, and the mobility state is set to a high mobility state when the measured number of cell reselections is more than the second threshold.
2. The method of claim 1 further comprising adjusting a timer value based on the mobility state.
3. The method of claim 2 further comprising adjusting the timer value to achieve an optimum paging efficiency.
4. The method of claim 2 further comprising scaling the timer value based on the mobility state.
5. The method of claim 2 further comprising:
adjusting the timer to a first value when the mobility state is set to the low mobility state;
adjusting the timer to a second value when the mobility state is set to the medium mobility state; and
adjusting the timer to a third value when the mobility state is set to the high mobility state.
6. A wireless transmit/receive unit (WTRU), comprising:
a processor configured to:
determine a measured number of cell reselections; and
set a mobility state based on the measured number of cell reselections;
wherein the mobility state is set to a low mobility state when the measured number of cell reselections is less than a first threshold, the mobility state is set to a medium mobility state when the measured number of cell reselections is more than the first threshold but less than a second threshold, and the mobility state is set to a high mobility state when the measured number of cell reselections is more than the second threshold.
7. The WTRU of claim 6 wherein the processor is further configured to adjust a timer value based on the mobility state.
8. The WTRU of claim 7 wherein the processor is further configured to adjust the timer value to achieve an optimum paging efficiency.
9. The WTRU of claim 7 wherein the processor is further configured to scale the timer value based on the mobility state.
10. The WTRU of claim 7 wherein the processor is further configured to:
adjust the timer to a first value when the mobility state is set to the low mobility state;
adjust the timer to a second value when the mobility state is set to the medium mobility state; and
adjust the timer to a third value when the mobility state is set to the high mobility state.