Question: In a 1.28 Mcps TDD scenario, what event marks the end of the cell re-selection delay for a User Equipment (UE) transitioning from one cell to another?
Option 1: Completion of the handover command transmission from the source cell
Option 2: Receipt of the first downlink packet in the new cell (Cell 2)
Option 3: Initiation of the RRC Connection Release procedure in the original cell (Cell 1)
Option 4: UE sending the SYNCH-UL sequence in the UpPTS for an RRC CONNECTION REQUEST in Cell 2
Explanation: The correct answer is Option 4 because, according to the provided context, the cell re-selection delay ends when the UE camps on Cell 2 and starts sending the SYNCH-UL sequence in the UpPTS. This action is specifically for sending an RRC CONNECTION REQUEST, which is a crucial step for performing a Location Registration on the new cell (Cell 2), marking the successful transition and the end of the re-selection delay.