C.3.3 Doppler/Temporal correlation

38.1513GPPNRRelease 17TSUser Equipment (UE) Multiple Input Multiple Output (MIMO) Over-the-Air (OTA) performance requirements

This measurement checks the Doppler/temporal correlation. For Doppler/Temporal correlation validation measurement, only Vertical validation is required.

The Doppler spectrum is measured with a spectrum analyser as shown in Figure C.3.3-1. In this case a signal generator transmits CW signal through the NR MIMO OTA test system. The signal is received by a test antenna within the test area. Finally, the signal is analysed by a spectrum analyser and the measured spectrum is compared to the target spectrum. This setup can be used to measure Doppler Spectrum of the Channel models defined in Annex C.1.

Method of measurement:

Figure C.3.3-1: Setup for Doppler measurements

Sine wave (CW, carrier wave) signal is transmitted from the signal generator. The signal is connected from the signal generator to fading emulator via cables. The fading emulator output signals are connected to power amplifier boxes via cables. The amplified signals are then transferred via cables to the probe antennas. The probe antennas radiate the signals over the air to the test antenna The Doppler spectrum is measured by the spectrum analyser and the trace is saved.

Signal generator settings:

Table C.3.3-1: Signal generator settings for Doppler/Temporal correlation measurements

Item

Unit

Value

Centre frequency

MHz

Downlink centre frequency

in Table C.3.1-1

Modulation

OFF

Spectrum analyser settings:

Table C.3.3-2: Spectrum analyser settings for Doppler/Temporal correlation measurements

Item

Unit

Value

Centre frequency

MHz

Downlink centre frequency

in Table C.3.1-1

Minimum Span

Hz

4 kHz

RBW

Hz

1

VBW

Hz

1

Number of points

16002

Averaging

100

Channel model specification:

Table C.3.3-3: Channel model specification for Doppler/Temporal correlation measurements

Item

Unit

Value

Centre frequency

MHz

Downlink centre frequency

in Table C.3.1-1

Channel model

As specified in Annex C.1

Mobile speed

km/h

100

Method of measurement result analysis: Measurement data file (Doppler power spectrum) is saved into hard drive. The data is read into, e.g., Matlab. The analysis is performed by taking the Fourier transformation of the Doppler spectrum. The resulting temporal correlation function is normalized such that . Then the function values left from the maximum is cut out. Further on the function values after, e.g. seven periods is cut out.