6.6 OTA Transmitted signal quality

37.145-23GPPActive Antenna System (AAS) Base Station (BS) conformance testingPart 2: radiated conformance testingRelease 17TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

6.6.1 General

Unless otherwise stated, the requirements in clause 6.6 apply during the transmitter ON period.

6.6.2 OTA Frequency Error

6.6.2.1 Definition and applicability

OTA frequency error is the measure of the difference between the actual AAS BS transmit frequency and the assigned frequency. The same source shall be used for RF frequency and data clock generation.

The OTA frequency error requirement is defined as a directional requirement at the RIB and shall be met within the OTA coverage range.

6.6.2.2 Minimum Requirement

For AAS BS in MSR operation the minimum requirement is defined in TS 37.105 [6], clause 9.6.2.2.

For AAS BS in single RAT UTRA operation the minimum requirement is defined in TS 37.105 [6], clause 9.6.2.3.

For AAS BS in single RAT E-UTRA operation the minimum requirement is defined in TS 37.105 [6], clause 9.6.2.4.

6.6.2.3 Test purpose

The test purpose is to verify that OTA frequency error is within the limit specified by the minimum requirement.

6.6.2.4 Method of test

Requirement is tested together with OTA modulation quality test, as described in clause 6.6.4.

NOTE: Measurement only in the OTA coverage range reference direction (see table 4.10-1, D11.4) is enough for OTA frequency error measurement.

6.6.2.5 Test Requirement

6.6.2.5.1 UTRA FDD test requirement

The OTA frequency error for every measured slot shall be between the minimum and maximum value specified in table 6.6.2.5.1-1.

Table 6.6.2.5.1-1: OTA frequency error test requirement

BS class	Accuracy
Wide Area BS	±(0.05 ppm + 12 Hz)
Medium Range BS	±(0.1 ppm + 12 Hz)
Local Area BS	±(0.1 ppm + 12 Hz)

NOTE: If the above Test Requirement differs from the Minimum Requirement then the Test Tolerance applied for this test is non-zero. The Test Tolerance for this test is defined in clause 4.1.2 and the explanation of how the Minimum Requirement has been relaxed by the Test Tolerance is given in annex C.

6.6.2.5.2 E-UTRA and NR test requirement

The modulated carrier frequency of each E-UTRA and NR carrier configured by the AAS BS shall be accurate to within the accuracy range given in table 6.6.2.5.2-1 observed over a period of one subframe (1 ms).

Table 6.6.2.5.2-1: OTA frequency error test requirement

BS class	Accuracy
Wide Area BS	±(0.05 ppm + 12 Hz)
Medium Range BS	±(0.1 ppm + 12 Hz)
Local Area BS	±(0.1 ppm + 12 Hz)

6.6.3 OTA Time alignment error

6.6.3.1 Definition and applicability

This requirement applies to frame timing in:

– UTRA single/multi-carrier transmissions and their combinations with MIMO or TX diversity.

– E-UTRA and/or NR single/multi-carrier transmissions and their combinations with MIMO or TX diversity.

– E-UTRA and /or NR carrier aggregation, with or without MIMO or TX diversity (except NR).

Frames of the UTRA/E-UTRA/NR signals present in the radiated domain are not perfectly aligned in time. In relation to each other, the RF signals present in the radiated domain may experience certain timing differences.

For a specific set of signals/transmitter configuration/transmission mode, the OTA Time Alignment Error (OTA TAE) is defined as the largest timing difference between any two different E-UTRA signals or any two different UTRA or any two different NR signals belonging to different reference symbols (e.g. CRS0 or CRS1 for E-UTRA, DMRS ports 1000 and 1001 for NR) in the radiated domain. The OTA time alignment error requirement is defined as a directional requirement at the RIB and shall be met within the OTA coverage range.

6.6.3.2 Minimum Requirement

For AAS BS in MSR operation the minimum requirement is defined in TS 37.105 [6], clause 9.6.3.2.

For AAS BS in single RAT UTRA operation the minimum requirement is defined in TS 37.105 [6], clause 9.6.3.3.

For AAS BS in single RAT E-UTRA operation the minimum requirement is defined in TS 37.105 [6], clause 9.6.3.4.

6.6.3.3 Test purpose

The test purpose is to verify that the OTA time alignment error is within the limit specified by the minimum requirement.

6.6.3.4 Method of test

6.6.3.4.1 Initial conditions

6.6.3.4.1.1 General test conditions

Test environment:

– normal; see annex G.2.

RF channels to be tested for single carrier:

– M; see clause 4.12.1.

Directions to be tested: The OTA coverage range reference direction (see table 4.10-1, D11.4).

For dual polarized systems the requirement shall be tested and met considering both polarisations. If the measurement antenna does not support dual polarization, time alignment error shall be measured under the condition that measurement antenna is aligned between the AAS BS polarisations such that it receives half the power from each polarisation.

6.6.3.4.1.2 UTRA FDD

Base Station RF Bandwidth positions to be tested for multi-carrier:

– B_RFBW, M_RFBW and T_RFBW in single-band operation; B_RFBW_T’_RFBW and B’_RFBW_T_RFBW in multi-band operation, see clause 4.12.1.

Refer to clause D.1.3 for a functional block diagram of the test set-up.

6.6.3.4.1.3 E-UTRA and NR

Base Station RF Bandwidth positions to be tested for multi-carrier and/or CA:

– M_RFBW in single-band operation, see clause 4.12.1; B_RFBW_T’_RFBW and B’_RFBW_T_RFBW in multi-band operation, see clause 4.12.1.

6.6.3.4.2 Procedure

6.6.3.4.2.1 General Procedure

1) Place the AAS BS at the positioner.

2) Align the manufacturer declared coordinate system orientation (see table 4.10-1, D9.2) of the AAS BS with the test system.

3) Orient the positioner (and BS) in order that the direction to be tested aligns with the test antenna.

4) Configure the beamforming settings of the AAS BS according to the direction to be tested.

6.6.3.4.2.2 UTRA FDD Procedure

5) If the AAS BS supports TX diversity or MIMO, set the AAS BS to transmit TM1, clause 4.12.2, at manufacturer’s declared rated carrier TRP, P_rated,c,TRP using TX diversity or MIMO.

6) Measure the time alignment error between the signals using different P-CPICH and CPICH signals on different beams.

7) If the AAS BS supports DC-HSDPA, 4C-HSDPA, NC-4C-HSDPA or 8C-HSDPA set the AAS BS to transmit according to TM1, without using TX diversity or MIMO, on all carriers configured using the applicable test configuration and corresponding power setting specified in clause 4.11.

8) Measure the time alignment error between the signals using the P-CPICH and CPICH signals on another beam.

9) If the AAS BS supports DB-DC-HSDPA or any of the multi-band 4C-HSDPA or 8C-HSDPA configurations set the AAS BS to transmit TM1 on two carriers belonging to different frequency bands, without using TX diversity or MIMO on any of the carriers.

10) Measure the time alignment error between the signals using different P-CPICH and CPICH signals on different beams.

In addition, for a multi-band RIB, the following steps shall apply:

11) For a multi-band RIB and single band tests, repeat the steps above per involved band where single band test configurations and test models shall apply with no carrier activated in the other band.

6.6.3.4.2.3 E-UTRA and NR Procedure

5) Set the AAS BS to transmit E-TM1.1 or NR-FR1-TM1.1 or any DL signal using TX diversity (except NR), MIMO transmission or carrier aggregation, using the configuration with the minimum number of cells and reference signals.

NOTE 1: For TX diversity and MIMO transmissions, different ports may be configured in E-TM (using p = 0 and 1).

NOTE 2: For MIMO transmission, different ports may be configured in NR-FR1-TM (using ports 1000 and 1001).

For an AAS BS declared to be capable of single carrier operation only, set the AAS BS to transmit according to manufacturer’s declared rated carrier TRP, P_rated,c,TRP.

If the AAS BS supports intra band contiguous or non-contiguous Carrier Aggregation set the AAS BS to transmit using the applicable test configuration and corresponding power setting specified in clause 4.11.

If the AAS BS supports inter band carrier aggregation set the AAS BS to transmit, for each band, a single carrier or all carriers, using the applicable test configuration and corresponding power setting specified in clause 4.11.

6) Measure the time alignment error between the different reference symbols on different beams on the carrier(s).

In addition, for a multi-band RIB, the following steps shall apply:

7) For a multi-band RIB and single band tests, repeat the steps above per involved band where single band test configurations and test models shall apply with no carrier activated in the other band.

6.6.3.5 Test Requirement

6.6.3.5.1 UTRA FDD test requirement

For Tx diversity and MIMO transmission, in the tested cell, TAE shall not exceed 0.35 T_c.

For transmission of multiple cells within a frequency band TAE shall not exceed 0.6 T_c.

For transmission of multiple cells in different frequency bands TAE shall not exceed 5.1 T_c.

6.6.3.5.2 E-UTRA test requirement

For MIMO or TX diversity transmissions, at each carrier frequency, TAE shall not exceed 90 ns.

For intra-band carrier aggregation, with or without MIMO or TX diversity, TAE shall not exceed 155 ns.

For intra-band non-contiguous carrier aggregation, with or without MIMO or TX diversity, TAE shall not exceed 285 ns.

For inter-band carrier aggregation, with or without MIMO or TX diversity, TAE shall not exceed 285 ns.

6.6.3.5.3 NR test requirement

For MIMO transmission, at each carrier frequency, OTA TAE shall not exceed 90 ns.

For intra-band contiguous carrier aggregation, with or without MIMO, OTA TAE shall not exceed 285 ns.

For intra-band non-contiguous carrier aggregation, with or without MIMO, OTA TAE shall not exceed 3.025 µs.

For inter-band carrier aggregation, with or without MIMO, OTA TAE shall not exceed 3.025 µs.

6.6.4 OTA modulation quality

6.6.4.1 Definition and applicability

OTA modulation quality is defined by the difference between the measured carrier signal and a reference signal. Modulation quality can be expressed e.g. as Peak Code Domain Error (PCDE) or Relative Code Domain Error (RCDE) or Error Vector Magnitude (EVM) for UTRA and Error Vector Magnitude (EVM) for E-UTRA.

The OTA modulation quality requirement is defined as a directional requirement at the RIB and shall be met within the OTA coverage range.

6.6.4.2 Minimum Requirement

For AAS BS the in MSR operation minimum requirement is defined in TS 37.105 [6], clause 9.6.4.2.

For AAS BS in single RAT UTRA operation the minimum requirement is defined in TS 37.105 [6], clause 9.6.4.3.

For AAS BS in single RAT E-UTRA operation the minimum requirement is defined in TS 37.105 [6], clause 9.6.4.4.

6.6.4.3 Test purpose

The test purpose is to verify that OTA modulation quality is within the limit specified by the minimum requirement.

6.6.4.4 Method of test

6.6.4.4.1 UTRA method of test

6.6.4.4.1.1 Initial conditions

Test environment: normal; see annex G.2.

RF channels to be tested for single carrier: B, M and T; see clause 4.12.1.

Base Station RF Bandwidth position to be tested:

– B_RFBW, M_RFBW and T_RFBW in single-band operation, see clause 4.12.1;

– B_RFBW_T’_RFBW and B’_RFBW_T_RFBW in multi-band operation, see clause 4.12.1.

Directions to be tested:

– The OTA coverage range reference direction (see table 4.10-2, D11.4) and the OTA coverage range maximum directions (see table 4.10-2, D11.5).

– The EVM test is performed once using the narrowest beamwidth supported by the AAS BS

For dual polarised systems the requirement shall be tested and met for each of the supported polarisations.

6.6.4.4.1.2 Procedure

6.6.4.4.1.2.1 General procedure

1) Place the AAS BS at the positioner.

2) Align the manufacturer declared coordinate system orientation (see table 4.10-1, D9.2) of the AAS BS with the test system.

3) Move the AAS BS on the positioner in order that the direction to be tested aligns with the test antenna.

4) Configure the beamforming settings of the AAS BS according to the direction to be tested.

6.6.4.4.1.2.2 EVM procedure

5) Set the AAS BS to output according to the applicable test configuration in clause 5 using the corresponding test models or set of physical channels in clause 4.12.2. For single carrier set the AAS BS to transmit at manufacturers declared rated carrier EIRP (P_rated,c,EIRP).

6) For each carrier, measure the Error Vector Magnitude and frequency error as defined in annex D.1.1 and the mean EIRP (in the conformance direction) of the signal. The measurement shall be performed on all 15 slots of the frame defined by the Test Model.

7) Using the same setting as in step 5), set the AAS BS to transmit a signal according to TM4, clause 4.12.2, with X value equal to 18, and repeat step 6). If the requirement in clause 6.6.4.5 is not fulfilled, decrease the total output power by setting the base station to transmit a signal according to TM4 with X greater than 18, and repeat step 6).

The following test shall be additionally performed if the base station supports HS-PDSCH transmission using 16QAM:

8) Using the same setting as in step 5), set the base station to transmit according to TM5, clause 4.12.2.

9) Repeat step 6).

In addition, for a multi-band RIB, the following steps shall apply:

10) For multi-band RIB and single band tests, repeat the steps above per involved band where single band test configurations and test models shall apply with no carrier activated in the other band.

6.6.4.4.1.2.3 PCDE procedure

6) Measure Peak code domain error according to annex D.1.1. The measurement shall be performed on all 15 slots of the frame defined by TM3. For an AAS BS declared to be capable of multi-carrier operation the measurement is performed on one of the carriers under test.

In addition, for a multi-band RIB, the following steps shall apply:

7) For multi-band RIB and single band tests, repeat the steps above per involved band where single band test configurations and test models shall apply with no carrier activated in the other band.

6.6.4.4.1.2.4 RCDE procedure

6) Measure average Relative code domain error according to annex E. The measurement shall be performed over one frame defined by TM6 and averaged as specified in TS 25.141 [10] clause 6.7.4.4.2. For an AAS BS declared to be capable of multi-carrier operation the measurement is performed on one of the carriers under test.

In addition, for a multi-band RIB, the following steps shall apply:

7) For multi-band RIB and single band tests, repeat the steps above per involved band where single band test configurations and test models shall apply with no carrier activated in the other band.

6.6.4.4.2 E-UTRA and NR method of test

6.6.4.4.2.1 Initial conditions

Test environment: normal; see annex G.2.

RF channels to be tested for single carrier: B and T; see clause 4.12.1.

RF bandwidth positions to be tested for multi-carrier and/or CA:

– B_RFBW and T_RFBW in single-band operation, see clause 4.12.1;

– B_RFBW_T’_RFBW and B’_RFBW_T_RFBW in multi-band operation, see clause 4.12.1.

Directions to be tested:

– OTA coverage range reference direction (see table 4.10-2, D11.4)

– OTA coverage range maximum directions (see table 4.10-2, D11.5).

Polarization to be tested: For dual polarized systems the requirement shall be tested and met for both polarizations.

6.6.4.4.2.2 Procedure

1) Place the AAS BS at the positioner.

2) Align the manufacturer declared coordinate system orientation (see table 4.10-1, D9.2) of the AAS BS with the test system.

3) Orient the positioner (and BS) in order that the direction to be tested aligns with the test antenna.

4) Configure the beamforming settings of the AAS BS according to the direction to be tested.

5) Set the AAS BS to output according to the applicable test configuration in clause 5 using the corresponding test models or set of physical channels in clause 4.12.2.

For single carrier operation only, set the AAS BS to transmit signal according to E-TM3.1 for E-UTRA (or sE-TM3.1-1 for subslot TTI, or sE-TM3.1-2 for slot TTI), at manufacturers declared rated carrier EIRP (P_rated,c,EIRP).

For NR operation, set the AAS BS to transmit signal according following procedure for BS type 1-O:

For BS type 1-O declared to be capable of single carrier operation only, set the BS to transmit a signal according to:

– NR-FR1-TM3.1b if 1024QAM is supported by BS without power back off

– or NR-FR1-TM 3.1b at manufacturer’s declared rated output power if 1024QAM is supported by BS with power back off, and NR-FR1-TM 3.1a if 256QAM is supported by BS without power back off

– or NR-FR1-TM 3.1b at manufacturer’s declared rated output power if 1024QAM is supported by BS with power back off and NR-FR1-TM 3.1a at manufacturer’s declared rated output power if 256QAM is supported by BS with power back off, and NR-FR1-TM3.1 at maximum power

– or NR-FR1-TM 3.1a if 1024QAM is not supported by BS and 256QAM is supported by BS without power back off

– or NR-FR1-TM3.1a at manufacturer’s declared rated output power if 256QAM is supported by BS with power back off and 1024QAM is not supported, and NR-FR1-TM3.1 at maximum power

– or NR-FR1-TM3.1 if highest modulation order supported by BS is 64QAM

– or NR-FR1-TM3.2 if highest modulation order supported by BS is 16QAM

– or NR-FR1-TM3.3 if highest modulation order supported by BS is QPSK.

6) Measure the EVM and frequency error as defined in annex D.

7) Repeat steps 5 and 6 for the following test models:

– For E-UTRA: repeat steps 5 and 6 for E-TM 3.2, E-TM 3.3 and E-TM2,

– For E-UTRA with subslot TTI: repeat steps 5 and 6 for sE-TM3.2-1, sE-TM3.3-1 and sE-TM2-1,

– For E-UTRA with slot TTI: repeat steps 5 and 6 for sE-TM3.2-2, sE-TM3.3-2 and sE-TM2-2.

If 256QAM is supported by BS for E-UTRA:

– For E-UTRA: repeat steps 5 and 6 for E-TM3.1a and E-TM2a,

– For E-UTRA with subslot TTI: repeat steps 5 and 6 for sE-TM3.1a-1 and sE-TM2a-1,

– For E-UTRA with slot TTI: repeat steps 5 and 6 for sE-TM3.1a-2 and sE-TM2a-2.

For E-UTRA test model E-TM2 and E-TM2a the OFDM symbol power shall be at the lower limit of the OTA dynamic range according to the test procedure in clause 6.4.4.4.2 and test requirements in clause 6.4.4.5.2.

For subslot TTI test model sE-TM2-1 and sE-TM2a-1 (or for sE-TM2-2 and sE-TM2a-2 for slot TTI) the OFDM symbol power shall be at the lower limit of the OTA dynamic range according to the test procedure in clause 6.4.4.4.2 and test requirements in clause 6.4.4.5.2.

For NR: repeat steps 5 and 6 for NR-FR1-TM2 if 256QAM is not supported by BS type 1-O or for NR-FR1-TM2a if 256QAM is supported by BS type 1-O but 1024QAM is not supported by BS type 1-O or for NR-FR1-TM2b if 1024QAM is supported by BS type 1-O. For NR-FR1-TM2, NR-FR1-TM2a and NR-FR1-TM2b the OFDM symbol power (in the conformance direction) shall be at the lower limit of the dynamic range according to the test procedure in clause 6.4.4.4.2.4 and test requirements in clause 6.4.4.5.3.

In addition, for multi-band RIB, the following steps shall apply:

8) For multi-band RIB and single band tests, repeat the steps above per involved band where single band test configurations and test models shall apply with no carrier activated in the other band.

6.6.4.5 Test Requirement

6.6.4.5.1 UTRA test requirement

The Error Vector Magnitude for each UTRA carrier and every measured slot shall be less than 18.5 % when the AAS BS is transmitting a composite signal using only QPSK modulation and shall be less than 13.5 % when the AAS BS is transmitting a composite signal that includes 16QAM modulation.

The peak code domain error for every measured slot shall not exceed 32 dB at spreading factor 256.

The average Relative Code Domain Error for 64QAM modulated codes shall not exceed 20 dB at spreading factor 16.

6.6.4.5.2 E-UTRA and NR test requirement

The EVM of each E-UTRA carrier for different modulation schemes on PDSCH or sPDSCH shall be less than the limits in table 6.6.4.5.2-1.

The EVM of each NR carrier for different modulation schemes on PDSCH shall be less than the limits in table 6.6.4.5.2-1a.

Table 6.6.4.5.2-1: EVM requirements for E-UTRA

Modulation scheme for PDSCH or sPDSCH	Required EVM (%)
QPSK	18.5
16QAM	13.5
64QAM	9
256QAM	4.5
1024QAM	3.5

Table 6.6.4.5.2-1a: EVM requirements for NR

Modulation scheme for PDSCH	Required EVM (%)
QPSK	18.5
16QAM	13.5
64QAM	9
256QAM	4.5
1024QAM	3.5 %¹ 3.8 %²
NOTE 1: This requirement is applicable for frequencies equal to or below 4.2 GHz. NOTE 2: This requirement is applicable for frequencies above 4.2 GHz.

The EVM requirement shall be applicable within a time period around the centre of the CP therefore the EVM requirement is tested against the maximum of the RMS average of 10 subframes at the two window W extremities.

For E-UTRA, the EVM window length (W) for normal CP and extended CP is specified in TS 36.104 [4], annex E.5.1.

Table 6.6.4.5.2-2: Void

For NR, the EVM window length (W) for normal CP and extended CP is specified in TS 38.104 [36], annex B.5.2.