6.7 Transmitter intermodulation

37.1413GPPMulti-Standard Radio (MSR) Base Station (BS) conformance testingNR, E-UTRA, UTRA and GSM/EDGERelease 17TS

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

6.7.1 Definition and applicability

The transmitter intermodulation requirement is a measure of the capability of the transmitter to inhibit the generation of signals in its nonlinear elements caused by presence of the wanted signal and an interfering signal reaching the transmitter via the antenna. The requirement applies during the transmitter ON period and the transmitter transient period. The transmitter intermodulation level is the power of the intermodulation products when an interfering signal is injected into the antenna connector.

For BS 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.

In case the test signal in clause 5 refer to single-RAT specifications following shall apply:

– For references to TS 25.141 [10], the method of test is specified in TS 25.141 [10], clause 6.6.4.

– For references to TS 25.142 [12], the method of test is specified in TS 25.142 [12], clause 6.7.4.

– For references to TS 36.141 [9], the method of test is specified in TS 36.141 [9], clause 6.7.4.

– For references to TS 38.141-1 [26], the method of test is specified in TS 38.141-1 [26], clause 6.7.4.

NOTE: In this case the test requirements of the present document defined in clauses 6.6.2.5 and 6.6.4.5 apply.

– For GSM/EDGE single-RAT requirements, the method of test is specified in TS 51.021 [11], applicable parts of clauses 6.7 and 6.11.

NOTE: In this case the test requirements of 51.021 [11] defined in the applicable clauses 6.7.3, 6.7.4, 6.11.3 and 6.11.4 apply.

6.7.2 Minimum requirement

The minimum requirement is in TS 37.104 [2] clause 6.7.1, 6.7.2 and 6.7.3.

6.7.2A Additional requirement for Band 41

The additional requirement for Band 41 in certain regions is in TS 37.104 [2] clause 6.7.4.

6.7.3 Test purpose

The test purpose is to verify the ability of the MSR BS transmitter 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 Annex B.2.

Base Station RF Bandwidth position to be tested: according to the initial conditions specified in clauses 6.6.1, 6.6.2 and 6.6.4.

Connect the signal analyzer to the Base Station antenna connector as shown in Annex D.1.2.

6.7.4.2 Procedure

6.7.4.2.1 General minimum requirement test procedure

1) Set the BS to transmit the test signal according to clause 5 at maximum output power according to the applicable test configuration.

2) Generate the interfering signal using E-TM1.1 as defined in TS 36.141 [9] clause 6.1.1.1, with 5 MHz channel bandwidth, at a centre frequency offset according to the conditions in Table 6.7.1-1 in TS 37.104 [2], 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.

3) Adjust ATT1 so that level of the E-UTRA interfering signal is as defined in Table 6.7.1-1 in TS 37.104 [2].

4) If the test signal is applicable according to clause 5, perform the Out-of-band emission tests as specified in clauses 6.6.2 and 6.6.4, for all third and fifth order intermodulation products which appear in the frequency ranges defined in clauses 6.6.2 and 6.6.4. The width of the intermodulation products shall be taken into account.

5) If the test signal is applicable according to clause 5, perform the Transmitter spurious emissions test as specified in clause 6.6.1, for all third and fifth order intermodulation products which appear in the frequency ranges defined in clause 6.6.1. The width of the intermodulation products shall be taken into account.

6) Verify that the emission level does not exceed the required level with the exception of interfering signal frequencies.

7) Repeat the test for the remaining interfering signal centre frequency offsets according to the conditions of Table 6.7.1-1 in TS 37.104 [2].

8) 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 a multi-band capable BS, the following step shall apply:

9) For multi-band capable 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. For multi-band capable BS with separate antenna connector, the antenna connector not being under test shall be terminated.

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*5MHz) for the nF1±mF2 products

(n*5MHz + 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.

6.7.4.2.2 Additional minimum requirement (BC1 and BC2) test procedure

1) Set the BS to transmit the test signal according to clause 5 at maximum output power according to the applicable test configuration.

2) Generate a CW signal as the interfering signal with a centre frequency offset of 0.8 MHz, but exclude interfering frequencies that are outside of the allocated downlink operating band or interfering frequencies in a sub-block gap or in the Inter RF Bandwidth gap, in case the gap is smaller than two times the interfering signal centre frequency offset.

3) Adjust ATT1 so that level of the interfering signal is as defined in Table 6.7.2-1 in TS 37.104 [2].

6) Verify that the emission level does not exceed the required level with the exception of interfering signal frequencies.

7) Repeat the test for interfering signal centre frequency offsets of 2.0MHz, 3.2MHz and 6.2MHz.

8) 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 a multi-band capable BS, the following step shall apply:

(n*BW_F1) for the nF1±mF2 products

(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.

6.7.4.2.3 Additional minimum requirement (BC3) test procedure

1) Set the BS to transmit the test signal according to clause 5 at maximum output power according to the applicable test configuration.

2) Generate the interfering signal according to Table 6.38A in TS 25.142 [12] at a centre frequency offset according to the conditions in Table 6.7.3-1 in TS 37.104 [2], but exclude interfering frequencies that are outside of the allocated downlink operating band.

3) Adjust ATT1 so that level of the interfering signal is as defined in Table 6.7.3-1 in TS 37.104 [2].

6) Verify that the emission level does not exceed the required level with the exception of interfering signal frequencies.

7) Repeat the test for the remaining interfering signal centre frequency offsets according to the conditions of Table 6.7.3-1 in TS 37.104 [2].

8) Repeat the test for the remaining test signals and physical channels in Table 4.9.2-1.

In addition, for a multi-band capable BS, the following step shall apply:

(n*BW_F1+ m*1.6MHz) for the nF1±mF2 products

(n*1.6MHz + 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.

6.7.5 Test requirements

6.7.5.1 General test requirement

In the frequency range relevant for this test, the transmitter intermodulation level shall not exceed the unwanted emission limits in clause 6.6.1, 6.6.2 and 6.6.4 in the presence of a wanted signal and an interfering signal according to Table 6.7.1‑1 in TS 37.104 [2] for BS operation in BC1, BC2 and BC3. The measurement may be limited to frequencies on which third and fifth order intermodulation products appear, considering the width of these products and excluding the bandwidths of the wanted and interfering signals.

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

For BS operating 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 BS capable of multi-band operation, 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 15 MHz, the requirement in the gap applies only for interfering signal offsets where the interfering signal falls completely within the Inter RF Bandwidth gap.

6.7.5.2 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 in clause 6.6.1, 6.6.2 and 6.6.4 in the presence of a wanted signal and an interfering signal according to Table 6.7.2-1 in TS 37.104 [2] for BS operation in BC2. The measurement may be limited to frequencies on which third and fifth order intermodulation products appear, considering the width of these products and excluding the bandwidths of the wanted and interfering signals.

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

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

For BS capable of multi-band operation, 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 RF Bandwidth gap equal to or larger than two times the interfering signal centre frequency offset. For BS capable of multi-band operation, the requirement is not applicable for BC1 band inside an Inter RF Bandwidth gap with a gap size equal to or larger than 5MHz.

6.7.5.3 Additional test requirement (BC3)

In the frequency range relevant for this test, the transmitter intermodulation level shall not exceed the unwanted emission limits in clause 6.6.1, 6.6.2 and 6.6.4 in the presence of a wanted signal and an interfering signal according to Table 6.7.3-1 in TS 37.104 [2] for BS operation in BC3. The measurement may be limited to frequencies on which third and fifth order intermodulation products appear, considering the width of these products and excluding the bandwidths of the wanted and interfering signals.

For BS capable of multi-band operation, 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 RF Bandwidth gap.

6.7.5.4 Additional test requirement for Band 41

In the frequency range relevant for this test, the transmitter intermodulation level shall not exceed the maximum levels according to Table 6.6.1.5.5-3 and Table 6.6.4.5.1-2 with a square filter in the first adjacent channel, in the presence of a wanted signal and an interfering signal according to Table 6.7.4‑1 in TS 37.104 [2] for a BS E-UTRA single-RAT operating in Band 41. The measurement may be limited to frequencies on which third and fifth order intermodulation products appear, considering the width of these products and excluding the bandwidths of the wanted and interfering signals.