Question: In 4C-HSDPA HS-DPCCH, what is the maximum allowable probability of ACK false alarm (P(DTX->ACK)) in multipath fading conditions at a specified Ec/N0 limit?
Option 1: 10^-1
Option 2: 5 × 10^-2
Option 3: 5 × 10^-3
Option 4: 10^-2
Explanation: The correct answer is based on the performance requirement for ACK false alarm in multipath fading conditions, which stipulates that the probability of incorrectly detecting a DTX (Discontinuous Transmission) as an ACK (Acknowledgement), P(DTX->ACK), should be **10^-2 or less**. This ensures reliable communication by limiting the error rate in signal detection under specified signal-to-noise ratio conditions (Ec/N0 limit). Option 4 directly aligns with this requirement, making it the correct choice.