TA Planning
The tracking area (TA) concept is introduced to LTE systems for UE location management. TAs are similar to location areas (LAs) in 2G/3G systems.
TAs provide the following functions:
LAs are defined the same at the access layer and core layer.
When a UE is idle, the core network knows the TA of the UE.
When a UE in idle state needs to be paged, paging is initiated in all the cells in the TA to which the UE belongs.
When PPT Voice needs broadcast, PTT Voice multicasts in all the cells in the TA to which the UE belongs.