Question: What event triggers the start of the cell re-selection delay timer in a User Equipment (UE) device?
Option 1: Receipt of a paging message from the current serving cell.
Option 2: A change in cell levels that prompts the UE to initiate camping on a new cell.
Option 3: Completion of a successful handover procedure from the serving cell.
Option 4: Expiration of the periodic Location Update timer.
Explanation: The cell re-selection delay begins when there's a change in cell levels significant enough for the UE to decide to camp on a new cell, marking the initiation of the process to send a CONNECTION REQUEST message for Location Registration on this new cell. This highlights the UE's dynamic response to changing radio conditions, ensuring seamless network connectivity.