Question: What triggers switching between the Normal Uplink (NUL) carrier and the Supplementary Uplink (SUL) carrier in a 5G network?
Option 1: An indication in Downlink Control Information (DCI), the Random Access procedure, or the Scheduling Request (SR) procedure.
Option 2: Only through handover procedures initiated by the Serving Cell.
Option 3: Exclusively via the Service Data Adaptation Protocol (SDAP) for QoS flow management.
Option 4: Through a combination of RRC reconfiguration and NAS signaling.
Explanation: Switching between NUL and SUL carriers involves moving UL transmissions between two carriers, facilitated by an indication in DCI for direct signaling, the Random Access procedure for initial or recovery scenarios, or similar scheduling adjustment procedures. This ensures seamless UL transmission transitions without necessitating higher-layer reconfigurations or handovers.