6.7 Transmit intermodulation
25.1423GPPBase Station (BS) conformance testing (TDD)Release 17TS
6.7.1 Definition and applicability
The transmit intermodulation performance is a measure of the capability of the transmitter 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 via the antenna.
The transmit intermodulation level is the power of the intermodulation products when a CDMA modulated interference signal is injected into the antenna connector at a power level of 30 dB lower than that of the rated total output power in the operating band.
6.7.1.1 3,84 Mcps TDD option
The carrier frequency of the interference signal shall be ±5 MHz, ±10 MHz and ±15 MHz offset from the subject signal carrier frequency, but excluding interference carrier frequencies outside of the UTRA frequency bands specified in 4.2a, 4.2b or 4.2c, respectively.
6.7.1.2 1,28 Mcps TDD option
The interfering signal offset from the subject signal shall be as defined in table 6.37F.
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.
Table 6.37F: Interfering signal frequency offset
|
Parameter |
Value |
|
Interfering signal frequency offset from the subject signal carrier frequency |
±1,6 MHz ±3,2 MHz ±4,8 MHz |
|
Interfering signal frequency offset from the edge of RF bandwidth |
±0.8MHz ±2.4 MHz ±4.0 MHz |
|
NOTE 1: Interference frequencies that are outside of the allocated frequency band 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. |
|
6.7.1.3 7,68 Mcps TDD option
The carrier frequency of the interference signal shall be ±10 MHz, ±20 MHz and ±30 MHz offset from the subject signal carrier frequency, but excluding interference carrier frequencies outside of the UTRA frequency bands specified in 4.2a, 4.2b or 4.2c, respectively.
6.7.2 Minimum Requirements
The transmit intermodulation level shall not exceed the out of band or the spurious emission requirements of subclause 6.6.2 and 6.6.3, respectively.
The normative reference for this requirement is TS 25.105 [1] subclause 6.7.1.
6.7.3 Test purpose
The test purpose is to verify the ability of the BS transmitter to restrict the generation of intermodulation products in its non linear 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
For 3,84 Mcps BS supporting 16QAM, the transmit intermodulation requirements shall be tested with the general test set up specified in section 6.7.4.1.1 and also with the special test set up for 16QAM capable BS specified in section 6.7.4.1.4.
For 1,28 Mcps BS supporting 16QAM, the transmit intermodulation requirements shall be tested with the general test set up specified in section 6.7.4.1.2 and also with the special test set up for 16QAM capable BS specified in section 6.7.4.1.3.
For 7,68 Mcps BS supporting 16QAM, the transmit intermodulation requirements shall be tested with the general test set up specified in section 6.7.4.5.1 and also with the special test set up for 16QAM capable BS specified in section 6.7.4.1.6.
6.7.4.1.0 General test conditions
Test environment: normal; see subclause 5.9.1.
RF channels to be tested for single carrier: B, M and T; see subclause 5.3.
RF bandwidth positions to be tested for multi-carrier: BRFBW, MRFBW and TRFBW in single band operation; see subclause 5.3.
6.7.4.1.1 3,84 Mcps TDD option – General test set up
(1) Connect the measuring equipment, the BS under test and the WCDMA signal generator as shown in figure 6.2.
(2) Set the parameters of the BS transmitted signal according to table 6.38. For MBSFN IMB operation the set of parameters for the transmitted signals is according to IMB test model 1 in subclause 6.1.1.1.
(3) Configure the WCDMA signal generator to produce an interference signal with a mean power level according to subclause 6.7.5. The interference signal shall be like-modulated as the BS transmitted signal, and the active time slots of both signals shall be synchronized. The carrier frequency of the interference signal shall be ±5 MHz, ±10 MHz and ±15 MHz offset from the carrier frequency of the wanted signal, but excluding interference frequencies outside of the UTRA frequency bands specified in 4.2a, 4.2b or 4.2c, respectively.
Figure 6.2: Measuring setup for Base Station transmit intermodulation testing
Table 6.38: Parameters of the BS transmitted signal for transmit intermodulation testing
|
Parameter |
Value/description |
|
TDD Duty Cycle |
TS i; i = 0, 1, 2, …, 14: transmit, if i is odd; receive, if i is even. |
|
Time slot carrying SCH |
TS0 |
|
Time slots under test |
TS i, i even and non zero |
|
BS output power setting |
PRAT |
|
Number of DPCH in each time slot under test |
9 |
|
Power of each DPCH |
1/9 of Base Station output power |
|
Data content of DPCH |
real life (sufficient irregular) |
6.7.4.1.2 1,28 Mcps TDD option – General test set up
(1) Connect the measuring equipment, the BS under test and the 1,28 Mcps TDD signal generator as shown in figure 6.2A.
(2) For a BS declared to be capable of single carrier operation only, set the parameters of the BS transmitted signal according to table 6.38A.
For a BS declared to be capable of multi-carrier operation, set the base station to transmit according to Table 6.38A on all carriers configured using the applicable test configuration and corresponding power setting specified in subclause 5.20 and 5.21.
(3) Configure the 1,28 Mcps TDD signal generator to produce an interference signal with a power level according to subclause 6.7.5. The interference signal shall be like-modulated as the BS transmitted signal, and the active time slots of both signals shall be synchronized. The interfering signal offset from the subject signal shall be according to Table 6.37F.
Figure 6.2A: Measuring set up for Base Station transmit intermodulation testing
Table 6.38A: Parameters of the BS 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) |
6.7.4.1.3 1,28 Mcps TDD option – Special test set up for 16QAM capable BS
This test set up only applies for 16QAM capable BS.
(1) Connect the measuring equipment, the BS under test and the 1,28 Mcps TDD signal generator as shown in figure 6.2B.
(2) For a BS declared to be capable of single carrier operation only, set the parameters of the BS transmitted signal according to table 6.38B at manufacturer’s declared output power, PRAT.
For a BS declared to be capable of multi-carrier operation, set the base station to transmit according to Table 6.38B on all carriers configured using the applicable test configuration and corresponding power setting specified in subclause 5.20 and 5.21.
(3) Configure the 1,28 Mcps TDDsignal generator to produce an interference signal with a power level according to subclause 6.7.5. The interference signal shall be like-modulated as the BS transmitted signal, and the active time slots of both signals shall be synchronized. The interfering signal offset from the subject signal shall be according to Table 6.37F.
Figure 6.2B: Measuring setup for Base Station transmit intermodulation testing
Table 6.38B: Parameters of the BS transmitted signal for transmit intermodulation testing for 1,28 Mcps TDD- 16QAM capable BS
|
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 |
|
HS-PDSCH modulation |
16QAM |
|
Number of HS-PDSCH in each time slot under test |
8 |
|
Power of each HS-PDSCH |
1/8 of Base Station output power |
|
Data content of HS-PDSCH |
real life (sufficient irregular) |
|
Spreading factor |
16 |
6.7.4.1.4 3,84 Mcps TDD option – Special test set up for 16QAM capable BS
(1) Connect the measuring equipment, the BS under test and the WCDMA signal generator as shown in figure 6.3.
(2) Set the parameters of the BS transmitted signal according to table 6.38C. For MBSFN IMB operation the set of parameters for the transmitted signals is according to IMB test model 2 in subclause 6.1.1.2.
(3) Configure the WCDMA signal generator to produce an interference signal with a mean power level according to subclause 6.7.5. The interference signal shall be like-modulated as the BS transmitted signal, and the active time slots of both signals shall be synchronized. The carrier frequency of the interference signal shall be ±5 MHz, ±10 MHz and ±15 MHz offset from the carrier frequency of the wanted signal, but excluding interference frequencies outside of the UTRA frequency bands specified in 4.2a, 4.2b or 4.2c, respectively.
Figure 6.3: Measuring setup for Base Station transmit intermodulation testing
Table 6.38C: Parameters of the BS transmitted signal for transmit intermodulation testing – 16QAM capable BS
|
Parameter |
Value/description |
|
TDD Duty Cycle |
TS i; i = 0, 1, 2, …, 14: transmit, if i is even; receive, if i is odd. |
|
Time slot carrying SCH |
TS0 |
|
Time slots under test |
TS i, i even and non zero |
|
BS output power setting |
PRAT |
|
HS-PDSCH modulation |
16QAM |
|
Number of HS-PDSCH in each time slot under test |
9 |
|
Power of each HS-PDSCH |
1/9 of Base Station output power |
|
Data content of HS-PDSCH |
real life (sufficient irregular) |
|
Spreading factor |
16 |
6.7.4.1.5 7,68 Mcps TDD option – General test set up
(1) Connect the measuring equipment, the BS under test and the WCDMA signal generator as shown in figure 6.4.
(2) Set the parameters of the BS transmitted signal according to table 6.38D.
(3) Configure the WCDMA signal generator to produce an interference signal with a mean power level according to subclause 6.7.5. The interference signal shall be like-modulated as the BS transmitted signal, and the active time slots of both signals shall be synchronized. The carrier frequency of the interference signal shall be ±10 MHz, ±20 MHz and ±30 MHz offset from the carrier frequency of the wanted signal, but excluding interference frequencies outside of the UTRA frequency bands specified in 4.2a, 4.2b or 4.2c, respectively.
Figure 6.4: Measuring setup for Base Station transmit intermodulation testing
Table 6.38D: Parameters of the BS transmitted signal for transmit intermodulation testing
|
Parameter |
Value/description |
|
TDD Duty Cycle |
TS i; i = 0, 1, 2, …, 14: transmit, if i is odd; receive, if i is even. |
|
Time slot carrying SCH |
TS0 |
|
Time slots under test |
TS i, i even and non zero |
|
BS output power setting |
PRAT |
|
Number of DPCH in each time slot under test |
9 |
|
Power of each DPCH |
1/9 of Base Station output power |
|
Data content of DPCH |
real life (sufficient irregular) |
6.7.4.1.6 7,68 Mcps TDD option – Special test set up for 16QAM capable BS
(1) Connect the measuring equipment, the BS under test and the WCDMA signal generator as shown in figure 6.5.
(2) Set the parameters of the BS transmitted signal according to table 6.38D.
(3) Configure the WCDMA signal generator to produce an interference signal with a mean power level according to subclause 6.7.5. The interference signal shall be like-modulated as the BS transmitted signal, and the active time slots of both signals shall be synchronized. The carrier frequency of the interference signal shall be ±10 MHz, ±20 MHz and ±30 MHz offset from the carrier frequency of the wanted signal, but excluding interference frequencies outside of the UTRA frequency bands specified in 4.2a, 4.2b or 4.2c, respectively.
Figure 6.5: Measuring setup for Base Station transmit intermodulation testing
Table 6.38D: Parameters of the BS transmitted signal for transmit intermodulation testing – 16QAM capable BS
|
Parameter |
Value/description |
|
TDD Duty Cycle |
TS i; i = 0, 1, 2, …, 14: transmit, if i is even; receive, if i is odd. |
|
Time slot carrying SCH |
TS0 |
|
Time slots under test |
TS i, i even and non zero |
|
BS output power setting |
PRAT |
|
HS-PDSCH modulation |
16QAM |
|
Number of HS-PDSCH in each time slot under test |
9 |
|
Power of each HS-PDSCH |
1/9 of Base Station output power |
|
Data content of HS-PDSCH |
real life (sufficient irregular) |
|
Spreading factor |
32 |
6.7.4.2 Procedure
1) Apply the single-band test procedures for out of band and spurious emissions as described in 6.6.2 and 6.6.3, respectively, at the frequencies of all third and fifth order intermodulation products. The frequency band occupied by the interference signal are excluded from the measurements.
In addition, for a multi-band capable BS, the following steps shall apply:
2) For multi-band capable BS and single band tests, repeat the steps above per involved band with no carrier activated in the other band.
3) 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 at frequencies (F1 ± 2F2) and (2F1 ± F2), the fifth order intermodulation products are at frequencies (2F1 ± 3F2), (3F1 ± 2F2), (4F1 ± F2) and (F1 ± 4F2), where F1 represents the frequencies within the bandwidth of the wanted signal and F2 represents the frequencies within the bandwidth of the CDMA modulated interference signal.
6.7.5 Test Requirements
NOTE: If the Test Requirement below 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 subclause 5.11 and the explanation of how the Minimum Requirement has been relaxed by the Test Tolerance is given in Annex D.
The power level of the CDMA modulated interference signal shall be 30 dB below the rated total output power in the operating band.
At the frequencies of all third and fifth order intermodulation products, the Test Requirements for out of band and spurious emissions as specified in subclauses 6.6.2.1.5 (Spectrum emission mask), 6.6.2.2.5 (ACLR) and 6.6.3.5 (Spurious emissions) shall be met.
The requirement is always applicable outside the Base Station RF bandwidth or maximum radio bandwidth.
For a BS capable of multi-band operation, the requirement applies relative to the RF bandwidth edges in each supported operating band. In case the inter RF bandwidth gap is less than 4.8 MHz, the requirement in the gap applies only for interfering signal offsets where the interfering signal falls completely within the inter RF bandwidth gap.