6.7F Transmit intermodulation for category NB1 and NB2
36.521-13GPPEvolved Universal Terrestrial Radio Access (E-UTRA)Part 1: Conformance testingRadio transmission and receptionRelease 17TSUser Equipment (UE) conformance specification
6.7F.1 Test purpose
To verify that the UE transmit intermodulation does not exceed the described value in the test requirement.
6.7F.2 Test applicability
This test case applies to all types of NB-IoT FDD UE release 13 and forward of UE category NB1.
This test case applies to all types of NB-IoT FDD UE release 14 and forward of UE category NB2.
This test case applies to all types of NB-IoT TDD UE release 15 and forward of category NB1 and NB2.
6.7F.3 Minimum conformance requirements
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 UE category NB1 and NB2 transmitter intermodulation attenuation is defined by the ratio of the mean power of the wanted signal to the mean power of the intermodulation product as defined in Table 6.7F.3-1 when an interfering CW signal is added at a level below the wanted signal at the transmitter antenna port. Both the wanted signal power and the intermodulation product power are measured through rectangular filter with measurement bandwidth shown in Table 6.7F.3-1.
Table 6.7F.3-1: UE category NB1 and NB2 transmitter IM requirement
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Parameters for transmitter intermodulation |
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BW Channel (UL) |
15 kHz (1 tone at sub-carrier 5 or 6) |
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Interference Signal Frequency Offset |
180 kHz |
360 kHz |
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Interference CW Signal Level |
-40dBc |
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Intermodulation Product |
-20 dBc |
-39 dBc |
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Measurement bandwidth |
30 kHz |
30 kHz |
The normative reference for this requirement is TS 36.101 [2] clause 6.7.1F.
6.7F.4 Test description
6.7F.4.1 Initial conditions
Initial conditions are a set of test configurations the UE needs to be tested in and the steps for the SS to take with the UE to reach the correct measurement state.
The initial test configurations consist of environmental conditions and test frequencies based on the subset of E-UTRA operating bands defined for NB-IoT in clause 5.2F. All of these configurations shall be tested with applicable test parameters shown in table 6.7F.4.1-1. The details of the uplink reference measurement channels (RMCs) are specified in Annexes A.2.4. Configurations of NPDSCH and NPDCCH before measurement are specified in [Annex C.2].
Table 6.7F.4.1-1: Test Configuration Table for FDD & TDD
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Initial Conditions |
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Test Environment as specified in TS 36.508[7] subclause 8.1.1 |
Normal |
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Test Frequencies as specified in TS 36.508 [7] subclause 8.1.3.1 |
Frequency ranges defined in Annex K.1.1 |
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Test Parameters |
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Configuration ID |
Downlink Configuration |
Uplink Configuration |
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N/A |
Modulation |
Ntones |
Sub-carrier spacing (kHz) |
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1 |
QPSK |
1@5 |
15kHz |
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1. Connect the SS to the UE antenna connectors as shown in TS 36.508 [7] Annex A, Figure A.2 using only main Tx/Rx antenna.
2. The parameter settings for the cell are set up according to TS 36.508 [7] subclause 8.1.4.3.
3. Downlink signals are initially set up according to Annex C.0, C.1, and C.3.0, and uplink signals according to Annex H.1.1 and H.4.0.
4. The UL Reference Measurement channels are set according to Table 6.7F.4.1-1.
5. Propagation conditions are set according to Annex B.0.
6. Ensure the UE is in State 2A-NB with CP CIoT Optimisation according to TS 36.508 [7] clause 8.1.5. Message contents are defined in clause 6.7F.4.3.
6.7F.4.3 Test procedure
1. SS sends uplink scheduling information for the UL HARQ process via NPDCCH DCI format N0 for C_RNTI to schedule the UL RMC according to Table 6.7F.4.1-1. Since the UE has no payload and no loopback data to send the UE sends uplink MAC padding bits on the UL RMC. (UE should be already transmitting PUMAX after Initial Conditions setting).
2. Measure the mean power of the UE in the channel bandwidth of the radio access mode according to the test configuration, which shall meet the requirements described in Table 6.2.3F.5-1. The measurement period is at least one sub-frame (1ms) for 15 KHz channel spacing. For TDD slots with transient periods are not under test.
3. Set the interference signal frequency below the UL carrier frequency using the first offset in table 6.7F.5-1.
4. Set the interference CW signal level according to table 6.7F.5-1.
5. Measure the rectangular filtered mean power of transmitting intermodulation product signals below and above the UL carrier frequency, and calculate the ratios with the power measured in step 2. The centre frequency of the measurement filter shall be (Interference signal frequency – Interference Signal Frequency Offset + 7.5kHz) and (UL carrier frequency – 15 kHz + Interference Signal Frequency Offset), respectively. For TDD slots with transient periods are not under test.
6. Set the interference signal frequency above the UL carrier frequency using the first offset in table 6.7F.5-1.
7. Measure the rectangular filtered mean power of transmitting intermodulation product signals below and above the UL carrier frequency, and calculate the ratios with the power measured in step 2. The centre frequency of the measurement filter shall be (UL carrier frequency – 15 kHz – Interference Signal Frequency Offset) and (Interference signal frequency + Interference Signal Frequency Offset + 7.5kHz) respectively. For TDD slots with transient periods are not under test.
Repeat the measurement using the second offset in table 6.7F.5-1.
6.7F.4.3 Message contents
Message contents are according to TS 36.508 [7] subclause 8.1.6.
6.7F.5 Test requirement
The ratio derived in step 5 and 7, shall not exceed the described value in table 6.7F.5-1
Table 6.7F.5-1: Transmit Intermodulation
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BW Channel (UL) |
15 kHz (1 tone) |
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Interference Signal Frequency Offset |
180 kHz |
360 kHz |
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Interference CW Signal Level |
-40dBc |
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|
Intermodulation Product |
-20 dBc |
-39 dBc |
|
Measurement bandwidth |
30 kHz |
30 kHz |