6.5 Transmitted signal quality

36.1413GPPBase Station (BS) conformance testingEvolved Universal Terrestrial Radio Access (E-UTRA)Release 17TS

The requirements in subclause 6.5 apply to the transmitter ON period.

6.5.1 Frequency error

6.5.1.1 Definition and applicability

Frequency error is the measure of the difference between the actual BS transmit frequency and the assigned frequency. The same source shall be used for RF frequency and data clock generation.

It is not possible to verify by testing that the data clock is derived from the same frequency source as used for RF generation. This may be confirmed by the manufacturer’s declaration.

6.5.1.2 Minimum Requirement

The minimum requirement is in TS 36.104 [2] subclause 6.5.1.

6.5.1.3 Test purpose

To verify that the Frequency Error is within the limit of the minimum requirement.

6.5.1.4 Method of test

Requirement is tested together with Error Vector Magnitude test, as described in subclause 6.5.2.

6.5.1.5 Test requirement

For E-UTRA, the modulated carrier frequency of each E-UTRA carrier configured by the BS shall be accurate to within the accuracy range given in Table 6.5.1-1 observed over a period of one subframe (1ms).

For NB-IoT, the modulated carrier frequency of each NB-IoT carrier configured by the BS shall be accurate to within the accuracy range given in Table 6.5.1-1 observed over a period of one subframe (1ms).

Table 6.5.1-1: Frequency error test requirement

BS class

Accuracy

Wide Area BS

± (0.05 ppm + 12 Hz)

Medium Range BS

± (0.1 ppm + 12 Hz)

Local Area BS

± (0.1 ppm + 12 Hz)

Home BS

± (0.25 ppm + 12 Hz)

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 and the explanation of how the Minimum Requirement has been relaxed by the Test Tolerance are given in Annex G.

6.5.2 Error Vector Magnitude

6.5.2.1 Definition and applicability

The Error Vector Magnitude is a measure of the difference between the ideal symbols and the measured symbols after the equalization. This difference is called the error vector. The equaliser parameters are estimated as defined in Annex F. The EVM result is defined as the square root of the ratio of the mean error vector power to the mean reference power expressed in percent.

6.5.2.2 Minimum Requirement

The minimum requirement is in TS 36.104 [2] subclause 6.5.2.

6.5.2.3 Test purpose

The test purpose is to verify that the Error Vector Magnitude is within the limit specified by the minimum requirement.

6.5.2.4 Method of test

6.5.2.4.1 Initial conditions

Test environment: normal; see Annex D.2.

RF channels to be tested for single carrier: B, M and T; see subclause 4.7.

Base Station RF Bandwidth positions to be tested for multi-carrier and/or CA: BRFBW, MRFBW and TRFBW in single-band operation, see subclause 4.7.1; BRFBW_T’RFBW and B’RFBW_TRFBW in multi-band operation, see subclause 4.7.1.

Connect the signal analyzer to the base station antenna connector as shown in Annex I.1.1.

6.5.2.4.2 Procedure

1) For a BS declared to be capable of single carrier operation only, set the BS to transmit a signal according to E-TM 3.1 (or sE-TM3.1-1 for subslot TTI, or sE-TM3.1-2 for slot TTI) at manufacturer’s declared rated output power.

For a BS declared to be capable of multi-carrier and/or CA operation, set the BS to transmit according to E-TM 3.1 (or sE-TM3.1-1 for subslot TTI, or sE-TM3.1-2 for slot TTI) on all carriers configured using the applicable test configuration and corresponding power setting specified in clause 4.10 and 4.11.

For a NB-IoT BS declared to be capable of single carrier operation, start transmission according to N-TM at manufacturer’s declared rated output power.

For a NB-IoT BS declared to be capable of multi-carrier operation, set the base station to transmit according to N-TM on all carriers configured using in the applicable test configuration and corresponding power setting specified in clause 4.10 and 4.11.

For an E-UTRA and NB-IoT standalone BS declared to be capable of multi-carrier operation, start transmission according to E-TM 3.1 on all E-UTRA carriers and N-TM on all NB-IoT carriers configured using in the applicable test configuration and corresponding power setting specified in clause 4.10 and 4.11.

2) Measure the EVM and frequency error as defined in Annex F.

3) For E-UTRA repeat steps 1 and 2 for E-TM 3.2 (or sE-TM3.2-1 for subslot TTI, or sE-TM3.2-2 for slot TTI), E-TM 3.3 (or sE-TM3.3-1 for subslot TTI, or sE-TM3.3-2 for slot TTI) and E-TM 2 (or sE-TM2-1 for subslot TTI, or sE-TM2-2 for slot TTI). Repeat steps 1 and 2 for E-TM3.1a (or sE-TM3.1a-1 for subslot TTI, or sE-TM3.1a-2 for slot TTI) and E-TM 2a (or sE-TM2a-1 for subslot TTI, or sE-TM2a-2 for slot TTI) for 256QAM, if supported by the BS. For E-TM2 (or sE-TM2-1 for subslot TTI, or sE-TM2-2 for slot TTI) and E-TM2a (or sE-TM2a-1 for subslot TTI, or sE-TM2a-2 for slot TTI) the OFDM symbol power shall be at the lower limit of the dynamic range according to the test procedure in subclause 6.3.2.4.2 and test requirements in subclause 6.3.2.5. Repeat steps 1 and 2 for E-TM3.1b and E-TM 2b for 1024QAM, if supported by the BS. For E-TM2b the OFDM symbol power shall be at the lower limit of the dynamic range according to the test procedure in subclause 6.3.2.4.2 and test requirements in subclause 6.3.2.5.

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

4) 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 in case of single-band or multi-band test shall be terminated.

6.5.2.5 Test requirement

The EVM of each E-UTRA carrier for different modulation schemes on PDSCH shall be less than the limits in table 6.5.2.5-1:

Table 6.5.2.5-1 EVM requirements for E-UTRA carrier

Modulation scheme for PDSCH or sPDSCH

Required EVM [%]

QPSK

18.5 %

16QAM

13.5 %

64QAM

9 %

256QAM

4.5%

1024QAM

3.5%

The EVM of each NB-IoT carrier on NB-PDSCH shall be less than the limits in table 6.5.2.5-1a:

Table 6.5.2.5-1a EVM requirements for NB-IoT carrier

Modulation scheme for NB-PDSCH

Required EVM [%]

QPSK

18.5 %

The EVM requirement shall be applicable within a time period around the centre of the CP therefore the EVM requirement is tested against the maximum of the RMS average of 10 subframes at the two window W extremities.

Table 6.5.2.5-2 and Table 6.5.2.5-2a specify EVM window length (W) for normal CP, the cyclic prefix length is 160 for symbols 0 and 144 for symbols 1-6.

Table 6.5.2.5-2 EVM window length for normal CP for E-UTRA

Channel
Bandwidth MHz

FFT size

Cyclic prefix length for symbols 0 in FFT samples

Cyclic prefix length for symbols 1‑6 in FFT samples

EVM window length W

Ratio of W to total CP for symbols 1‑6* [%]

1.4

128

10

9

5

55.6

3

256

20

18

12

66.7

5

512

40

36

32

88.9

10

1024

80

72

66

91.7

15

1536

120

108

102

94.4

20

2048

160

144

136

94.4

* Note: These percentages are informative and apply to symbols 1 through 6. Symbol 0 has a longer CP and therefore a lower percentage.

Table 6.5.2.5-2a EVM window length for normal CP for NB-IoT

FFT size

Cyclic prefix length for symbols 0 in FFT samples

Cyclic prefix length for symbols 1‑6 in FFT samples

EVM window length W

Ratio of W to total CP for symbols 1‑61 [%]

128

10

9

3

33.3

Note 1: These percentages are informative and apply to symbols 1 through 6. Symbol 0 has a longer CP and therefore a lower percentage.

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 Annex G. The explanation of how the Minimum Requirement has been relaxed by the Test Tolerance is given in Annex G.

6.5.3 Time alignment error

6.5.3.1 Definition and applicability

Frames of the LTE signals present at the BS transmitter antenna port(s) are not perfectly aligned in time. In relation to each other, the RF signals present at the BS transmitter antenna port(s) experience certain timing differences.

For a specific set of signals/transmitter configuration/transmission mode, time alignment error (TAE) is defined as the largest timing difference between any two signals. This test is only applicable for eNode B supporting TX diversity MIMO transmission, carrier aggregation and their combinations.

6.5.3.2 Minimum Requirement

The minimum requirement is in TS 36.104 [2] subclause 6.5.3.

6.5.3.3 Test Purpose

To verify that the timing alignment error in TX diversity, MIMO transmission, carrier aggregation and their combinations is within the limit specified by the minimum requirement.

6.5.3.4 Method of Test

6.5.3.4.1 Initial Conditions

Test environment: normal; see Annex D.2.

RF channels to be tested for single carrier: M; see subclause 4.7.

Base Station RF Bandwidth positions to be tested for multi-carrier and/or CA: MRFBW in single-band operation, see subclause 4.7.1; BRFBW_T’RFBW and B’RFBW_TRFBW in multi-band operation, see subclause 4.7.1.

1) Connect two base station RF antenna ports to the measurement equipment according to Annex I.1.3. If available terminate the other unused antenna ports.

6.5.3.4.2 Procedure

1) Set the base station to transmit E-TM1.1 or any DL signal using TX diversity, MIMO transmission or carrier aggregation.

NOTE: For TX diversity and MIMO transmission, different ports may be configured in E-TM (using p = 0 and 1).

For a BS declared to be capable of single carrier operation only, set the BS to transmit according to manufacturer’s declared rated output power.

If the BS supports intra band contiguous or non-contiguous Carrier Aggregation set the base station to transmit using the applicable test configuration and corresponding power setting specified in clause 4.10 and 4.11.

If the BS supports inter band carrier aggregation set the base station to transmit, for each band, a single carrier or all carriers, using the applicable test configuration and corresponding power setting specified in sub clause 4.10 and 4.11.

For a NB-IoT BS declared to be capable of single carrier operation, start transmission according to N-TM at manufacturer’s declared rated output power.

For a NB-IoT BS declared to be capable of multi-carrier operation, set the base station to transmit according to N-TM on all carriers configured using in the applicable test configuration and corresponding power setting specified in clause 4.10 and 4.11.

For an E-UTRA and NB-IoT standalone BS declared to be capable of multi-carrier operation, start transmission according to E-TM1.1 on all E-UTRA carriers and N-TM on all NB-IoT carriers configured using in the applicable test configuration and corresponding power setting specified in clause 4.10 and 4.11.

2) Measure the time alignment error between the reference symbols on the carrier(s) from active antenna port(s).

3) Repeat the step 1 and 2 for any other possible configuration of transmit antennas.

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

4) 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 in case of single-band or multi-band test shall be terminated.

6.5.3.5 Test Requirement

For E-UTRA:

– For MIMO or TX diversity transmissions, at each carrier frequency, TAE shall not exceed 90 ns.

– For intra-band carrier aggregation, with or without MIMO or TX diversity, TAE shall not exceed 155 ns.

– For intra-band non-contiguous carrier aggregation, with or without MIMO or TX diversity, TAE shall not exceed 285 ns.

– For inter-band carrier aggregation, with or without MIMO or TX diversity, TAE shall not exceed 285 ns.

For NB-IoT:

– For TX diversity transmissions, at each carrier frequency, TAE shall not exceed 90 ns.

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 and the explanation of how the Minimum Requirement has been relaxed by the Test Tolerance are given in Annex G.

6.5.4 DL RS power

6.5.4.1 Definition and applicability

For E-UTRA, DL RS power is the resource element power of Downlink Reference Symbol.

The absolute DL RS power is indicated on the DL-SCH. The absolute accuracy is defined as the maximum deviation between the DL RS power indicated on the DL-SCH and the DL RS power of each E-UTRA carrier at the BS antenna connector.

For NB-IoT, DL NRS power is the resource element power of the Downlink Narrow-band Reference Signal.

The absolute DL NRS power is indicated on the DL-SCH. The absolute accuracy is defined as the maximum deviation between the DL NRS power indicated on the DL-SCH and the DL NRS power of each NB-IoT carrier at the BS antenna connector.

6.5.4.2 Minimum Requirement

The minimum requirement is in TS 36.104 [2] subclause 6.5.4.

6.5.4.3 Test purpose

The test purpose is to verify that the DL RS/NRS power is within the limit specified by the minimum requirement.

6.5.4.4 Method of test

6.5.4.4.1 Initial conditions

Test environment: normal; see Annex D.2.

RF channels to be tested for single carrier: B, M and T; see subclause 4.7.

Connect the signal analyzer to the base station antenna connector as shown in Annex I.1.1.

6.5.4.4.2 Procedure

For E-UTRA, set-up BS transmission at manufacturer’s declared rated output power. Channel set-up shall be according to E-TM 1.1.

For NB-IoT, Set-up BS transmission at manufacturer’s declared rated output power. Channel set-up shall be according to N-TM.

Measure the RS transmitted power according to annex F.

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

– For multi-band capable BS and single band tests, repeat the steps above per involved band where single carrier 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.

6.5.4.5 Test requirement

For E-UTRA, DL RS power of each E-UTRA carrier shall be:

within 2.9 dB of the DL RS power indicated on the DL-SCH for carrier frequency f ≤ 3.0GHz.

within 3.2 dB of the DL RS power indicated on the DL-SCH for carrier frequency 3.0GHz < f ≤ 4.2GHz.

For NB-IoT, DL NRS power of each NB-IoT carrier shall be:

within 2.9 dB of the DL NRS power indicated on the DL-SCH for carrier frequency f ≤ 3.0GHz.

NOTE 1: 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 Annex G. The explanation of how the Minimum Requirement has been relaxed by the Test Tolerance is given in Annex G.

NOTE 2: PDSCH in E-TM1.1 is configured as "all 0" and DL RS power is not indicated on PDSCH during the measurement. The absolute DL RS power indicated on the DL-SCH can be calculated as Pmax,c – 10log10 (12* NRB) dBm, where NRB is the transmission bandwidth configuration of E-TM1.1.