Question: In a cellular network, what event marks the end of the cell re-selection delay for a User Equipment (UE) transitioning to a new cell?
Option 1: When the UE's signal strength from the old cell drops below a certain threshold.
Option 2: Upon completion of the handover procedure initiated by the network.
Option 3: The moment the UE sends an RR (Radio Resource) Channel Request message for location update to the new cell.
Option 4: When the UE receives and decodes system information from the new cell.
Explanation: The correct answer is Option 3 because, according to the definition of cell re-selection delay, this period ends when the UE, in response to changed cell levels (e.g., stronger signal from a new cell), not only selects a new cell to camp on but also takes the action of sending an RR Channel Request message for a location update to that new cell. This action signifies the UE's commitment to the new cell and is the marker for the end of the delay period in question.