Question: In a TDD network, 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 sent by the source cell
Option 2: Receipt of the first downlink synchronization signal in the new cell
Option 3: UE starts sending the SYNCH-UL sequence in the UpPTS for an RRC CONNECTION REQUEST in the new cell
Option 4: Successful authentication with the new cell by the UE
Explanation: The correct answer is Option 3 because the cell re-selection delay ends when the UE begins sending the SYNCH-UL sequence in the UpPTS as part of initiating an RRC CONNECTION REQUEST on the new cell, signifying the UE's successful transition and attempt to establish a connection with the new cell.