Question: In E-UTRA, for PUCCH format 1b with Channel Selection, what is the number of encoded ACK bits per sub-frame when evaluating ACK missed detection probability?
Option 1: 2 bits (AA)
Option 2: 3 bits (AAA)
Option 3: Variable, dependent on TDD or FDD mode
Option 4: 4 bits (AAAA)
Explanation: According to E-UTRA transmission requirements for PUCCH format 1b with Channel Selection, the number of encoded ACK bits per sub-frame is standardized to ensure consistent and reliable communication. This standardization enables accurate evaluation of ACK missed detection probability, crucial for maintaining network performance. The correct number, as per telecom standards for this scenario, is indeed 4 bits (AAAA), ensuring each sub-frame carries a consistent amount of acknowledgement information.