C.3.5 Cross-polarization

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

This measurement checks how well the measured vertically or horizontally polarized power levels follow expected values. The test setup for cross-polarization is the same as PDP validation in Figure C.3.2-1.

Method of measurement: Step the emulation and store traces from VNA.

VNA settings:

Table C.3.5-1: VNA settings for cross-polarization

Item	Unit	Value
Centre frequency	MHz	Downlink Centre Frequency in Table C.3.1-1
Span	MHz	40
Number of traces		1000
Number of points		802
Averaging		1

Channel model specification:

Table C.3.5-2: Channel model specification for cross-polarization.

Item	Unit	Value
Centre frequency	MHz	Downlink centre frequency in Table C.3.1-1
Distance between traces in channel model	wavelength (Note)	> 2
Channel model		As specified in Annex C.1
Mobile speed (**	km/h	30
NOTE: Time [s] = distance [λ] / MS speed [λ/s] MS speed [λ/s] = MS speed [m /s] / Speed of light [m/s] * Centre frequency [Hz] (** The mobile speed is valid for the Time Domain Alternative method only

Measurement Procedure:

Step the emulation and store traces from VNA. i.e., run the emulation to CIR number 1, pause, measure VNA trace, run the emulation to CIR number 10, pause, measure VNA trace. Continue until 1000 VNA traces are measured.

a. Use a vertically polarized sleeve dipole to measure the V component.

b. Use a horizontally polarized (vertically oriented) magnetic loop dipole, or a horizontally polarized sleeve dipole measured in four orthogonal horizontal positions and summed to measure the H component.

Method of measurement result analysis:

Measured VNA traces (frequency responses and are saved into a hard drive. The data is read into, e.g., Matlab. The frequency responses are averaged in power over time and frequency and the V/H ratio calculated as follows:

Beam-Specific Block Diagram

It is assumed that the beams are mapped to the inputs of the channel emulator as follows:

– Beam 1: Input 1 and Input 2

– Beam 2: Input 3 and Input 4 (CDL-C UMa only)

Figure C.3.5-1: Setup for Beam-Specific V/H measurements (Beam 1)

Figure C.3.5-2: Setup for Beam-Specific V/H measurements (Beam 2 CDL-C UMa only)

Time Domain Alternative Method:

The power in the Vertical and Horizontal polarizations can also be measured in time domain. The measurement setup for Beam-Specific are presented in Figures C.3.5-3, and C.3.5-4.

Figure C.3.5-3: Setup for Beam-Specific V/H measurements (Beam 1)

Figure C.3.5-4: Setup for Beam-Specific V/H measurements (Beam 2 CDL-C UMa only)

The instruments settings are the same as those in C.3.4-6 and C.3.4-7. The measurement analysis is the same as that of the frequency domain method setting the summation over f to a single point.

The reference V/H-ratios for CDL-C UMa and CDL-C UMi channel model validation are defined in table C.3.5-3 and C.3.5-4, respectively.

Table C.3.5-3: Reference V/H-ratios for CDL-C UMa

UMa C, fc ≤ 2.5 GHz	Beam 1	Input 1+2:  V/H = 0 dB
	Beam 2	Input 3+4:  V/H = 0 dB
UMa C, fc > 2.5 GHz	Beam 1	Input 1+2:  V/H = 0 dB
	Beam 2	Input 3+4:  V/H = 0 dB

Table C.3.5-4: Reference V/H-ratios for CDL-C UMi

UMi C, fc ≤ 2.5 GHz	Beam 1	Inputs 1+2: V/H = 0 dB
UMi C, fc > 2.5 GHz	Beam 1	Inputs 1+2: V/H = 0 dB