6.7 Transmitter intermodulation

37.145-13GPPActive Antenna System (AAS) Base Station (BS) conformance testingPart 1: conducted conformance testingRelease 17TS

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

6.7.1 Definition and applicability

6.7.1.1 General

The 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. The requirement applies during the transmitter ON period and the transmitter transient period.

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

The transmitter intermodulation level is the power of the intermodulation products when an interfering signal is injected into the TAB connector.

For AAS BS there are two types of transmitter intermodulation cases captured by the transmitter intermodulation requirement:

1) Co-location transmitter intermodulation in which the interfering signal is from a co-located base station.

2) Intra-system transmitter intermodulation in which the interfering signal is from other transmitter units within the AAS BS.

For AAS BS, the co-location transmitter intermodulation requirement is considered sufficient if the interfering signal for the co-location requirement is higher than the declared interfering signal for intra-system transmitter intermodulation requirement.

For TAB connectors capable of multi-band operation where multiple bands are mapped on separate antenna connectors, the single-band requirements apply regardless of the interfering signals position relative to the Inter RF Bandwidth gap.

6.7.2 Minimum requirement

The minimum requirement for MSR operation are defined in TS 37.105 [8], clause 6.7.2.

The minimum requirement for UTRA operation are defined in TS 37.105 [8], clause 6.7.3.

The minimum requirement for UTRA operation are defined in TS 37.105 [8], clause 6.7.4.

6.7.3 Test purpose

The test purpose is to verify the ability of the transmitter units associated with the TAB connector 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 via the antenna to below specified levels.

6.7.4 Method of test

6.7.4.1 Initial conditions

Test environment:

– normal; see clause B.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:

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

6.7.4.2 Procedure

The minimum requirement is applied to all TAB connectors, they may be tested one at a time or multiple TAB connectors may be tested in parallel as shown in clause D.1.1. Whichever method is used the procedure is repeated until all TAB connectors necessary to demonstrate conformance have been tested.

1) Connect TAB connector to measurement equipment as shown in annex D.1.2. All TAB connectors not under test shall be terminated.

2) The measurement device 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.

3) Set the set the TAB connector to transmit:

a) For MSR:

– Set the TAB connector 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 TAB connector declared to be capable of single carrier operation only, set the TAB connector to transmit a signal according to TM1, clause 4.12.2, at the manufacturer’s declared rated output power, P_rated,c,TABC.

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

c) For UTRA TDD:

– For a TAB connector declared to be capable of single carrier operation only, set the parameters of the transmitted signal according to table 6.7.4.2-1.

– For a TAB connector declared to be capable of multi-carrier operation, set to transmit according to table 6.7.4.2-1on all carriers.

Table 6.7.4.2-1: Parameters of the transmitted signal for transmit intermodulation testing
for 1,28 Mcps TDD

Parameter	Value/description
TDD Duty Cycle	TS i; I = 0, 1, 2, 3, 4, 5, 6: transmit, if i is 0,4,5,6; receive, if i is 1,2,3.
Time slots under test	TS4, TS5 and TS6
Number of DPCH in each time slot under test	8
Power of each DPCH	1/8 of Base Station output power
Data content of DPCH	real life (sufficient irregular)

d) For E-UTRA:

– TAB connector declared to be capable of single carrier operation only, set the TAB connector to transmit a signal according to E- TM1.1 in clause 4.12.2, at manufacturer’s declared rated output power P_rated,c,TABC.

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

4) 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 6.7.2.1-1 in TS 37.105 [8], 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 of according to the conditions of table 6.7.3.1-1 in TS 37.105 [8], 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 UTRA TDD:

– The signal shall be like-modulated as the transmit signal and the active time slots of both signals shall be synchronized, with a frequency offset of according to the conditions of table 6.7.3.2-1 in TS 37.105 [8], 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.

d) 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 6.7.4.1-1 in TS 37.105 [8], 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.

5) Adjust ATT1 so that level of the interfering signal is as defined in:

a) For MSR:

i. General co-location table 6.7.2.1-1 in TS 37.105 [8].

ii. Additional co-location (BC1 and BC2) table 6.7.2.2-1 in TS 37.105 [8].

iii. Additional co-location (BC3) table 6.7.2.3-1 in TS 37.105 [8].

iv. Intra-system table 6.7.2.5-1 in TS 37.105 [8].

b) For UTRA FDD:

i. General co-location table 6.7.3.1-1 in TS 37.105 [8].

ii. Intra-system table 6.7.3.3-1 in TS 37.105 [8].

c) For UTRA TDD:

i. General co-location for 1,28 Mcps TDD UTRA table 6.7.3.2-1 in TS 37.105 [8].

ii. Intra-system table 6.7.3.3-1 in TS 37.105 [8].

d) For E-UTRA:

i. General co-location table 6.7.4.1-1 in TS 37.105 [8].

ii. Void

iii. Intra-system table 6.7.4.131 in TS 37.105 [8].

6) If the test signal is applicable according to clause 5, perform the unwanted emission tests specified in clauses 6.6.3, 6.6.4 and 6.6.5, for all third and fifth order intermodulation products which appear in the frequency ranges defined in clauses 6.6.3, 6.6.4 and 6.6.5. The width of the intermodulation products shall be taken into account.

7) If the test signal is applicable according to clause 5, perform the Transmitter spurious emissions test as specified in clause 6.6.6, for all third and fifth order intermodulation products which appear in the frequency ranges defined in clause 6.6.6. The width of the intermodulation products shall be taken into account.

8) Verify that the emission level does not exceed the required level in clause 6.7.5 with the exception of interfering signal frequencies.

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

a) For MSR:

i. General co-location table 6.7.2.1-1 in TS 37.105 [8].

ii. Additional co-location (BC1 and BC2) table 6.7.2.2-1 in TS 37.105 [8].

iii. Additional co-location (BC3) table 6.7.2.3-1 in TS 37.105 [8].

iv. Intra-system table 6.7.2.5-1 in TS 37.105 [8].

b) For UTRA FDD:

i. General co-location table 6.7.3.1-1 in TS 37.105 [8].

ii. Intra-system table 6.7.3.3-1 in TS 37.105 [8].

c) For UTRA TDD:

i. General co-location for 1,28 Mcps TDD UTRA table 6.7.3.2-1 in TS 37.105 [8].

ii. Intra-system table 6.7.3.3-1 in TS 37.105 [8].

d) For E-UTRA:

i. General co-location table 6.7.4.1-1 in TS 37.105 [8].

ii. Void

iii. Intra-system table 6.7.4.131 in TS 37.105 [8].

10) Repeat the test for the remaining test signals defined in clause 5 for requirements 6.6.1, 6.6.2 and 6.6.4.

In addition, for multi-band TAB connector(s), the following steps shall apply:

11) For multi-band TAB connectors 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: 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*BW_F1+ m*BW_F2) for the nF1±mF2 products;

– (n*BW_F2 + m*BW_F1) for the nF2±mF1 products;

where BW_F1represents the test signal RF bandwidth or channel bandwidth in case of single carrier, or sub-block bandwidth, and BW_F2 represents interfering signal bandwidth.

6.7.5 Test requirements

6.7.5.1 MSR test requirements

6.7.5.1.1 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 6.6.6, operating band unwanted emission in clause 6.6.5 and ACLR in clause 6.6.3 in the presence of a wanted signal and an interfering signal according clause 6.7.4. for a TAB connector 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 TAB connectors 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 TAB connectors supporting operation in multiple operating bands, 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.

6.7.5.1.2 Additional test requirement (BC1 and 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 TAB connectors 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 TAB connectors 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 TAB connectors supporting operation in multiple operating bands, 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 TAB connectors 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.

6.7.5.1.3 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 6.6.6, operating band unwanted emission in clause 6.6.5 and ACLR in clause 6.6.3 in the presence of a wanted signal and an interfering signal according clause 6.7.4.

For TAB connectors supporting operation in multiple operating bands, 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.

6.7.5.1.4 Intra-system test requirement

In the frequency range relevant for this test, the transmitter intermodulation level shall not exceed the unwanted emission limits specified for operating band unwanted emission in clause 6.6.5 and ACLR in clause 6.6.3 in the presence of a wanted signal and an interfering signal according clause 6.7.4 for a TAB connector operating in BC1, BC2 and BC3.

6.7.5.2 Single RAT UTRA operation

6.7.5.2.1 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 6.6.5 and clause 6.6.6 in the presence of interfering signal according to according clause 6.7.4.

For TAB connectors 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 TAB connectors supporting operation in multiple operating bands, 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.

6.7.5.2.2 General test requirement for UTRA TDD

For TAB connectors 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.

6.7.5.2.3 Intra-system test requirement

6.7.5.4 Single RAT E-UTRA operation

6.7.5.4.1 General test requirement

In the frequency range relevant for this test, the transmitter intermodulation level shall not exceed the unwanted emission limits in clauses 6.6.6, 6.6.5 and 6.6.3 in the presence of an E-UTRA interfering signal according to according clause 6.7.4.

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 TAB connectors supporting operation in multiple operating bands, 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.