## 10 Modulation accuracy

25.1163GPPRelease 17TSUTRA repeater radio transmission and reception (LCR TDD)

## 10.1 Error Vector Magnitude

The modulation accuracy is defined by the Error Vector Magnitude (EVM), which is a measure of the difference between the theoretical waveform and a modified version of the measured waveform. This difference is called the error vector. The measured waveform is modified by first passing it through a matched root raised cosine filter with bandwidth 1.28MHz and roll-off =0.22. The waveform is then further modified by selecting the frequency, absolute phase, absolute amplitude and chip clock timing so as to minimise the error vector. The EVM result is defined as root of the ratio of the mean error vector power to the mean reference signal power expressed as a %.

The measurement interval is one power control group (timeslot). The repeater shall operate with an ideal LCR TDD signal in the pass band of the repeater at a level, which produce the maximum rated output power per channel, as specified by the manufacturer.

### 10.1.1 Minimum requirement

The Error Vector Magnitude shall not be worse than 8 %.

## 10.2 Peak code domain error

The code domain error is computed by projecting the error vector power onto the code domain at a specific spreading factor. The error power for each code is defined as the ratio to the mean power of the reference waveform expressed in dB. And the Peak Code Domain Error is defined as the maximum value for Code Domain Error. The measurement interval is one timeslot.

### 10.2.1 Minimum requirement

The peak code domain error shall not exceed -30 dB at spreading factor 16.