Question: In a 5G NR network, after a Primary Cell (PCell) activation, when can a User Equipment (UE) start reporting valid ACK/NACK for the PCell?
Option 1: Immediately after the UE receives the PCell activation command
Option 2: From the first UL (Uplink) slot that occurs after the beginning of a DL (Downlink) slot, following a specific timing (k1) after DL data reception
Option 3: Only after successfully receiving and decoding all system information blocks on the PCell
Option 4: After a predefined fixed delay from the start of the T1 timer
Explanation: This is because, after a PCell activation, the UE must synchronize its uplink responses with the downlink slots. The correct timing for starting to report valid ACK/NACK is tied to the first uplink slot following a downlink slot, considering a specific timing offset (k1) that accounts for the processing time between receiving downlink data and sending an acknowledgement, ensuring synchronized communication.