Question: For a Base Station (BS) in an E-UTRA network using 15 kHz subcarrier spacing, what is the defined time duration for the basic unit of Error Vector Magnitude (EVM) measurement when supporting short Transmission Time Interval (sTTI) feature?
Option 1: One radio frame (10ms)
Option 2: One slot (0.5ms)
Option 3: One subframe (1ms) for both TTI and sTTI
Option 4: One sTTI in the time domain, with a specific duration less than 1ms
Explanation: According to E-UTRA specifications, when supporting the sTTI feature with 15 kHz subcarrier spacing, the basic unit of EVM measurement is defined over one short Transmission Time Interval (sTTI) in the time domain. Since sTTI durations are shorter than regular TTIs (e.g., less than 1ms), this option correctly reflects the specification for reduced latency transmissions.