Question: Which of the following RRC messages indicates a successful outgoing hard handover, contributing to the "Successful outgoing hard handovers per neighbour cell relation" measurement?
Option 1: RRC Connection Release
Option 2: Radio Bearer Setup Complete
Option 3: Transport Channel Reconfiguration Failure
Option 4: PHYSICAL CHANNEL RECONFIGURATION COMPLETE (among other specific completes)
Explanation: The correct answer is Option 4 because it includes the receipt of specific RRC messages from the UE to the source RNC, indicating a successful outgoing hard handover. This is crucial for accurately counting successful handovers in network performance management, particularly for maintaining efficient neighbour cell relations. Options 1, 2, and 3 either do not match or imply failure/rejection, which wouldn't contribute to the "successful" handover count.