Question: In a scenario where a User Equipment (UE) is camping on a 7.68 Mcps TDD cell and then reselects to a GSM cell due to changed cell quality levels, what triggers the UE to send a LOCATION UPDATING REQUEST message?
Option 1: Receipt of a dedicated paging message from the new GSM cell.
Option 2: Completion of the cell re-selection delay timer after determining the new GSM cell is better ranked.
Option 3: Immediate detection of a stronger signal from the GSM cell without evaluating ranking.
Option 4: The moment the UE's cell quality level change assessment indicates the new GSM cell is sufficiently better to warrant reselection.
Explanation: A LOCATION UPDATING REQUEST message is sent after the UE determines a new cell (in this case, a GSM cell) is sufficiently better than the current one (a 7.68 Mcps TDD cell), prompting a need for location update due to cell reselection, tied to evaluating cell quality levels and deciding to reselect a better-ranked cell.