Question: In a UTRAN TDD to E-UTRAN TDD cell handover scenario, what marks the starting point for measuring the handover delay in UTRA 1.28Mcps TDD UEs supporting release 8 and later releases of E-UTRA TDD?
Option 1: The end of the last Transmission Time Interval (TTI) containing an RRC message implying hard handover.
Option 2: The initiation of the first RRC connection setup request in the target cell.
Option 3: The completion of the security authentication procedure with the new base station.
Option 4: The receipt of the handover command by the User Equipment (UE).
Explanation: According to telecom handover principles, the delay is typically measured from the last significant event in the source cell to the first transmission in the target cell. In this context, the end of the last TTI with an RRC message for hard handover serves as a clear, measurable point marking the handover initiation, making it the logical starting point for measuring the handover delay. This aligns with efficient network operation principles, ensuring minimal disruption to ongoing communications.