6.8 OTA Transmitter intermodulation

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

6.8.1 Definition and applicability

The OTA transmitter intermodulation requirement is a measure of the capability of the transmitter unit to inhibit the generation of signals in its non-linear elements caused by presence of the wanted signal and an interfering signal reaching the transmitter unit via the RDN and antenna array from a co-located base station. The requirement applies during the transmitter ON period and the transmitter transient period.

The requirement applies at each RIB supporting transmission in the operating band.

The transmitter intermodulation level is the total radiated power of the intermodulation products when an interfering signal is injected into the CLTA.

For OTA AAS BS, the transmitter intermodulation requirement is captured by the co-location transmitter intermodulation scenario case, in which the interfering signal is injected into the CLTA.

6.8.2 Minimum Requirement

The minimum requirement for AAS BS in MSR operation is defined in TS 37.105 [6], clause 9.8.2.

The minimum requirement for AAS BS in single RAT UTRA operation is defined in TS 37.105 [6], clause 9.8.3.

The minimum requirement for AAS BS in single RAT E-UTRA operation is defined in TS 37.105 [6], clause 9.8.4.

6.8.3 Test purpose

The test purpose is to verify the ability of the transmitter units associated with the RIB under test to restrict the generation of intermodulation products in its nonlinear elements caused by presence of the wanted signal and an interfering signal reaching the transmitter unit via the RDN and antenna array from a co-located base station to below specified levels.

6.8.4 Method of test

6.8.4.1 Initial conditions

Test environment:

– normal; see annex G.2.

RF channels to be tested for single carrier:

– M; see clause 4.12.1.

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

– MRFBW in single-band RIB, see clause 4.12.1; BRFBW_T’RFBW and B’RFBW_TRFBW in multi-band RIB, see clause 4.12.1.

In addition, for multi-band RIB:

– For BRFBW_T’RFBW, emission testing above the highest operating band may be omitted.

– For B’RFBW_TRFBW, emission testing below the lowest operating band may be omitted.

– FFS

Directions to be tested for:

As the requirement is based on TRP the beam pattern(s) may be set up to optimise the TRP measurement procedure (see annex F) as long as the required TRP level is achieved.

6.8.4.2 Procedure

1) Select a CLTA according to parameters given in Table 4.15.2.2-1.

2) Place the CLTA according to parameters given in Table 4.15.2.3-1.

3) The test antenna(s) shall be dual (or single) polarized covering the same frequency range as the AAS BS and the emission frequencies.

4) Several test antennas are required to cover both the AAS BS and the whole emission frequency range.

5) Connect the test antenna and CLTA to the measurement equipment as shown in Annex D1.5, Figures D.1.5-1.

6) During the OTA emission measurements at the test antenna conducted output(s), both AAS BS and CLTA are rotated around same axis.

7) The OTA unwanted emissions measurement method shall be TRP, according to the procedure described in Annex F.

8) The measurement device (signal analyzer) characteristics shall be:

– Detection mode: True RMS.

– The emission power should be averaged over an appropriate time duration to ensure the measurement is within the measurement uncertainty in Table 4.1.2.2-1.

9) Set the AAS BS to transmit:

a) For MSR:

– Set the AAS BS to transmit maximum power according to the applicable test configuration in clause 5 using the corresponding test models or set of physical channels in clause 4.11.

b) For UTRA FDD:

– For a AAS BS declared to be capable of single carrier operation only, set the AAS BS to transmit maximum power according to TM1, clause 4.12.2, at the manufacturer’s declared rated carrier TRP, Prated,c,TRP.

– For a AAS BS declared to be capable of multi-carrier operation, set the AAS BS to transmit maximum power according to TM1 on all carriers configured using the applicable test configuration and corresponding power setting specified in clause 4.11.

c) For E-UTRA:

For AAS BS declared to be capable of single carrier operation only, set the AAS BS to transmit maximum power according to E-TM1.1 in clause 4.12.2, at manufacturer’s declared rated carrier TRP, Prated,c,TRP.

– For a AAS BS declared to be capable of multi-carrier and/or CA operation, set the AAS BS to transmit maximum power according to E-TM1.1 on all carriers configured using the applicable test configuration and corresponding power setting specified in clause 4.11.

10) Generate the interfering signal:

a) For MSR:

– using E-TM1.1 as defined in clause 4.12.2, with 5 MHz channel bandwidth, at a centre frequency offset according to the conditions in table 6.8.5.1.1-1, but exclude interfering frequencies that are outside of the allocated downlink operating band or interfering frequencies that are not completely within the sub-block gap or within the Inter RF Bandwidth gap.

b) For UTRA FDD:

– in accordance to TM1, clause 4.12.2 with a frequency offset according to the conditions of table 6.8.5.2.1-1, but exclude interfering signal frequencies that are outside of the allocated downlink operating band or interfering signal frequencies that are not completely within the sub-block gap or within the Inter RF Bandwidth gap.

c) For E-UTRA:

– according to E-TM1.1, as defined in clause 4.12.2, with 5 MHz channel bandwidth and a centre frequency offset according to the conditions of table 6.8.5.3.1-1, but exclude interfering frequencies that are outside of the allocated downlink operating band or interfering frequencies that are not completely within the sub-block gap or within the Inter RF Bandwidth gap.

11) Connect the interfering signal to the CLTA input interfaces, equally dividing the power among supported polarizations. Adjust the interfering signal level at the CLTA conducted input(s) as defined in:

a) For MSR:

i. General co-location table 6.8.5.1.1-1.

ii. Additional co-location (BC1 and BC2) table 6.8.5.1.2-1.

iii. Additional co-location (BC3) table 6.8.5.1.3-1.

b) For UTRA FDD:

i. General co-location table 6.8.5.2.1-1 .

c) For E-UTRA:

i. General co-location table 6.8.5.3.1-1.

ii. Void

12) If the interfering signal is applicable according to clause 5, perform the unwanted emission tests specified in clauses 6.7.3 (OTA ACLR), 6.7.4 (OTA spectrum mask) and 6.7.5 (OTA OBUE), for all third and fifth order intermodulation products which appear in the frequency ranges defined in clauses 6.7.3, 6.7.4 and 6.7.5 (NOTE 2). The width of the intermodulation products shall be taken into account.

13) If the interfering signal is applicable according to clause 5, perform the transmitter spurious emissions test as specified in clause 6.7.6 (OTA spurious emission), except OTA co-location spurious emission, for all third and fifth order intermodulation products which appear in the frequency ranges defined in clause 6.7.6 (NOTE 2). The width of the intermodulation products shall be taken into account.

14) Verify that the emission level does not exceed the required level in clause 6.8.5 (Test requirements) with the exception of interfering signal frequencies.

15) Repeat the test for the remaining interfering signal centre frequency offsets according to the conditions of:

a) For MSR:

i. General co-location table 6.8.5.1.1-1.

ii. Additional co-location (BC1 and BC2) table 6.8.5.1.2-1.

iii. Additional co-location (BC3) table 6.8.5.1.3-1.

b) For UTRA FDD:

i. General co-location table 6.8.5.2.1-1 .

c) For E-UTRA:

i. General co-location table 6.8.5.3.1-1.

ii. Void

16) Repeat the test for the remaining interfering signals defined in clause 5 for requirements 6.7.3 (OTA ACLR), 6.7.4 (OTA spectrum mask), 6.7.5 (OTA OBUE) and 6.7.6 (OTA spurious emission), except OTA co-location spurious emission.

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

17) For multi-band AAS BS 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.

NOTE 1: The third order intermodulation products are centred at 2F1±F2 and 2F2±F1. The fifth order intermodulation products are centred at 3F1±2F2, 3F2±2F1, 4F1±F2, and 4F2±F1 where F1 represents the test signal centre frequency or centre frequency of each sub-block and F2 represents the interfering signal centre frequency. The widths of intermodulation products are:

– (n*BWF1 + m*BWF2) for the nF1±mF2 products;

– (n*BWF2 + m*BWF1) for the nF2±mF1 products;

where BWF1 represents the test signal RF bandwidth or channel bandwidth in case of single carrier, or sub-block bandwidth, and BWF2 represents the interfering signal bandwidth.

NOTE 2: During the conformance test the interfering signal can be applied on one side of the wanted signal, while the transmitter intermodulation emission is measured only on the opposite side of the wanted signal. This applies for intermodulation products which are within the operating band or OBUE region.

6.8.5 Test Requirement

6.8.5.1 MSR test requirements

6.8.5.1.1 General test requirement

In the frequency range relevant for this test the transmitter intermodulation level shall not exceed the unwanted emission limits specified for transmitter spurious emission in clause 6.7.6 (except co-location spurious emission), operating band unwanted emission in clause 6.7.5 and ACLR in clause 6.7.3 in the presence of a wanted signal and an interfering signal according to table 6.8.5.1.1-1 for an OTA AAS BS operating in BC1, BC2 and BC3.

The requirement is applicable outside the edges of the Base Station RF Bandwidth. The interfering signal offset is defined relative to the Base Station RF Bandwidth edges or radio bandwidth edges.

For RIB supporting operation in non-contiguous spectrum, the requirement is also applicable inside a sub-block gap for interfering signal offsets where the interfering signal falls completely within the sub-block gap. The interfering signal offset is defined relative to the sub-block edges.

For multi-band RIBs, the requirement applies relative to the Base Station RF Bandwidth edges of each operating band. In case the inter Base Station RF Bandwidth gap is less than 15 MHz, the requirement in the gap applies only for interfering signal offsets where the interfering signal falls completely within the inter Base Station RF Bandwidth gap.

Table 6.8.5.1.1-1: Interfering and wanted signals for the OTA transmitter intermodulation requirement

Parameter

Value

Wanted signal type

E-UTRA or NR signal

Interfering signal type

E-UTRA signal of channel bandwidth 5 MHz

Interfering signal power level applied to the CLTA

min(46 dBm, Prated,t,TRP)

Interfering signal centre frequency offset from Base Station RF Bandwidth edge or edge of sub-block inside a gap

±2.5 MHz

±7.5 MHz

±12.5 MHz

NOTE 1: Interfering signal positions that are partially or completely outside of any downlink operating band of the RIB is excluded from the requirement, unless the interfering signal positions fall within the frequency range of adjacent downlink operating bands in the same geographical area. In case that none of the interfering signal positions fall completely within the frequency range of the downlink operating band, TS 37.141 provides further guidance regarding appropriate test requirements.

NOTE 2: In certain regions, NOTE 1 is not applied in Band 1, 3, 8, 9, 11, 18, 19, 21, 28, 32 operating within 1 475.9 MHz to 1 495.9 MHz, 34.

NOTE 3: For OTA AAS BS with dual polarization, the interfering signal power shall be equally divided between the supported polarizations at the CLTA.

6.8.5.1.2 Additional test requirement (BC1 and BC2)

In the frequency range relevant for this test the transmitter intermodulation level shall not exceed the unwanted emission limits specified for transmitter spurious emission in clause 6.7.6 (except co-location spurious emission), operating band unwanted emission in clause 6.7.5 and ACLR in clause 6.7.3 in the presence of a wanted signal and an interfering signal according to table 6.8.5.1.2-1 for an OTA AAS BS operating in BC2.

The requirement is applicable outside the edges of the Base Station RF Bandwidth for BC2. The interfering signal offset is defined relative to the Base Station RF Bandwidth edges.

For RIBs supporting operation in non-contiguous spectrum in BC1 or BC2, the requirement is also applicable inside a sub-block gap with a gap size larger than or equal to two times the interfering signal centre frequency offset. For RIBs supporting operation in non-contiguous spectrum in BC1, the requirement is not applicable inside a sub-block gap with a gap size equal to or larger than 5 MHz. The interfering signal offset is defined relative to the sub-block edges.

For multi-band RIBs, the requirement applies relative to the Base Station RF Bandwidth edges of a BC2 operating band. The requirement is also applicable for BC1 and BC2 inside an inter Base Station RF Bandwidth gap equal to or larger than two times the interfering signal centre frequency offset. For RIBs supporting operation in multiple operating bands, the requirement is not applicable for BC1 band inside an inter Base Station RF Bandwidth gap with a gap size equal to or larger than 5 MHz.

Table 6.8.5.1.2-1: Interfering and wanted signals for the OTA transmitter intermodulation requirement

Parameter

Value

Wanted signal type

E-UTRA and/or NR UTRA signal

Interfering signal type

CW

Interfering signal power level applied to the CLTA

min(46 dBm, Prated,t,TRP))

Interfering signal centre frequency offset from Base Station RF Bandwidth edge or edge of sub-block inside a gap

> abs(800) kHz for CW interfering signal

NOTE 1: Interfering signal positions that are partially or completely outside of any downlink operating band of the RIB are excluded from the requirement.

NOTE 2: For OTA AAS BS with dual polarization, the interfering signal power shall be equally divided between the supported polarizations at the CLTA.

6.8.5.1.3 Additional test requirement (BC3)

In the frequency range relevant for this test, the transmitter intermodulation level shall not exceed the unwanted emission limits specified for transmitter spurious emission in clause 6.7.6 (except co-location spurious emission), operating band unwanted emission in clause 6.7.5 and ACLR in clause 6.7.3 in the presence of a wanted signal and an interfering signal according table 6.8.5.1.3-1 an OTA AAS BS operating in BC3.

For multi-band RIBs, the requirement applies relative to the Base Station RF Bandwidth edges of each operating band. In case the Inter RF Bandwidth gap is less than 3.2 MHz, the requirement in the gap applies only for interfering signal offsets where the interfering signal falls completely within the inter Base Station RF Bandwidth gap.

Table 6.8.5.1.3-1: Interfering and wanted signals for the OTA transmitter intermodulation requirement (BC3)

Parameter

Value

Wanted signal type

E-UTRA and/or UTRA and/or NR signal

Interfering signal type

1,28 Mcps UTRA TDD signal of channel bandwidth 1,6 MHz

Interfering signal power level applied to the CLTA

min(46 dBm, Prated,t,TRP)

Interfering signal centre frequency offset from Base Station RF Bandwidth edge or edge of sub-block inside a gap

±0,8 MHz

±1,6 MHz

±2,4 MHz

NOTE 1: Interfering signal positions that are partially or completely outside of any downlink operating band of the base station are excluded from the requirement.

NOTE 2: For OTA AAS BS with dual polarization, the interfering signal power shall be equally divided between the supported polarizations at the CLTA.

6.8.5.2 Single RAT UTRA operation

6.8.5.2.1 General test requirement for UTRA FDD

In the frequency range relevant for this test, the transmitter intermodulation level shall not exceed the out of band emission or the spurious emission requirements of clause 6.7.4 (OTA spectrum mask) and clause 6.7.6 (OTA spurious emission, except co-location spurious emission), in the presence of interfering signal according to table 6.8.5.2.1-1.

For RIBs supporting operation in non-contiguous spectrum, the requirement is also applicable inside a sub-block gap for interfering signal offsets where the interfering signal falls completely within the sub-block gap. The interfering signal offset is defined relative to the sub-block edges.

For multi-band RIBs, the requirement is also applicable inside an Inter RF Bandwidth gap for interfering signal offsets where the interfering signal falls completely within the Base Station RF Bandwidth gap.

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.

Table 6.8.5.2.1-1: Interfering and wanted signal frequency offset for OTA transmitter intermodulation requirement

Parameter

Value

Wanted signal type

UTRA

Interfering signal type

UTRA

Interfering signal power level applied to the CLTA

min(46 dBm, Prated,t,TRP)

Interfering signal centre frequency offset from the lower (upper) edge of the wanted signal or edge of sub-block inside a gap

-2,5 MHz

-7,5 MHz

-12,5 MHz

+2,5 MHz

+7,5 MHz

+12,5 MHz

NOTE 1: Interference frequencies that are outside of any allocated frequency band for UTRA-FDD downlink specified in clause 4.6 are excluded from the requirement, unless the interfering signal positions fall within the frequency range of adjacent downlink operating bands in the same geographical area.

NOTE 2: NOTE 1 is not applied in Band I, III, VI, VIII, IX, XI, XIX, XXI, and XXXII operating within 1 475.9 MHz to 1 495.9 MHz, in certain regions.

NOTE 3: For OTA AAS BS with dual polarization, the interfering signal power shall be equally divided between the supported polarizations at the CLTA.

6.8.5.3 Single RAT E-UTRA operation

6.8.5.3.1 General test requirement

In the frequency range relevant for this test, the transmitter intermodulation level shall not exceed the unwanted emission limits in clauses 6.7.6 (OTA spurious emission, except co-location spurious emission), 6.7.5 (OTA OBUE) and 6.7.3 (OTA ACLR) in the presence of an E-UTRA interfering signal according to according to table 6.8.5.3.1-1.

The requirement is applicable outside the Base Station RF Bandwidth or radio bandwidth. The interfering signal offset is defined relative to the Base Station RF Bandwidth edges or radio bandwidth edges.

For RIBs supporting operation in non-contiguous spectrum, the requirement is also applicable inside a sub-block gap for interfering signal offsets where the interfering signal falls completely within the sub-block gap. The interfering signal offset is defined relative to the sub-block edges.

For multi-band RIBs, the requirement applies relative to the Base Station RF Bandwidth edges of each supported operating band. In case the Inter RF Bandwidth gap is less than 15 MHz, the requirement in the gap applies only for interfering signal offsets where the interfering signal falls completely within the inter Base Station RF Bandwidth gap.

Table 6.8.5.3.1-1: Interfering and wanted signals for the OTA transmitter intermodulation requirement

Parameter

Value

Wanted signal

E-UTRA single carrier, or multi-carrier, or multiple intra-band contiguously or non-contiguously aggregated carriers

Interfering signal type

E-UTRA signal of channel bandwidth 5 MHz

Interfering signal power level applied to the CLTA

min(46 dBm, Prated,t,TRP)

Interfering signal centre frequency offset from the lower (upper) edge of the wanted signal or edge of sub-block inside a sub-block gap

±2,5 MHz

±7,5 MHz

±12,5 MHz

NOTE 1: Interfering signal positions that are partially or completely outside of any downlink operating band of the base station are excluded from the requirement, unless the interfering signal positions fall within the frequency range of adjacent downlink operating bands in the same geographical area. In case that none of the interfering signal positions fall completely within the frequency range of the downlink operating band, TS 36.141 provides further guidance regarding appropriate test requirements.

NOTE 2: In certain regions, NOTE 1 is not applied in Band 1, 3, 8, 9, 11, 18, 19, 21, 28, 32 operating within 1 475.9 MHz to 1 495.9 MHz, 34.

NOTE 3: For OTA AAS BS with dual polarization, the interfering signal power shall be equally divided between the supported polarizations at the CLTA.

6.8.5.3.2 Void

Table 6.8.5.3.2-1: Void