Question: What happens to the content of a MAC (Medium Access Control) Protocol Data Unit (PDU) after it is built for transmission on a dynamic uplink grant, in relation to the outcome of a Listen Before Talk (LBT) procedure?
Option 1: The MAC PDU content is modified based on the LBT outcome to optimize transmission efficiency.
Option 2: The MAC PDU is discarded if the LBT outcome indicates an unfavorable transmission condition.
Option 3: The MAC PDU's priority is adjusted according to the LBT outcome before transmission.
Option 4: The content of the MAC PDU does not change, regardless of the LBT outcome.
Explanation: Once a MAC PDU is constructed for transmission on a dynamic uplink grant, its content remains unchanged, even if the Listen Before Talk (LBT) procedure yields an unfavorable outcome. This ensures predictable behavior in varying network conditions and simplifies protocol implementation.