Measured EVM for different SNR values. EVM results obtained by measuring when CQI = 12 and SNR ranges from 11 to 38 dB for the interpolation factors I=1,2,3. 95% confidence regions are provided. We have also evaluated the EVM for CQI = 1 (4-QAM) and CQI = 8 (16-QAM), and the results are almost indistinguishable. Corresponding relative error curves are plotted when the SNR is set to 38 dB, showing an excellent agreement.