Question: In a TDD system for UEs supporting HSDPA, how is the HS-DSCH data throughput measured for variable reference channels?
Option 1: By analyzing the UE's transmission power levels over a set period.
Option 2: By counting the amount of data successfully received at the UE, as indicated by ACK/NACK signalling on the HS-SICH.
Option 3: Through direct measurement of the downlink signal strength at the UE.
Option 4: By evaluating the round-trip time of packets between the SS and the UE.
Explanation: The correct answer reflects the method where HS-DSCH data throughput is measured by monitoring the success of data reception at the UE, via ACK/NACK signals on the HS-SICH, indicating successful data receipt. This directly assesses effective throughput from the perspective of successful data transfer to the UE.