6.7 Transmit modulation

25.1413GPPBase Station (BS) conformance testing (FDD)Release 17TS

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

6.7.1 Error Vector Magnitude

6.7.1.1 Definition and applicability

The Error Vector Magnitude is a measure of the difference between the reference waveform and the measured waveform. This difference is called the error vector. Both waveforms pass through a matched Root Raised Cosine filter with bandwidth 3.84 MHz and roll-off =0.22. Both waveforms are then further modified by selecting the frequency, absolute phase, absolute amplitude and chip clock timing so as to minimise the error vector. The EVM result is defined as the square root of the ratio of the mean error vector power to the mean reference power expressed as a %. The measurement interval is one timeslot as defined by the C-PICH (when present) otherwise the measurement interval is one timeslot starting with the beginning of the SCH. The requirement is valid over the total power dynamic range as specified in 25.104 [1] clause 6.4.3. See Annex E of this specification for further details

6.7.1.2 Minimum Requirement

The minimum requirement is in TS 25.104 [1] clause 6.8.2.

6.7.1.3 Test Purpose

To verify that the Error Vector Magnitude is within the limit specified by the minimum requirement.

6.7.1.4 Method of Test

This test method includes the procedure for clause 6.3.4 Frequency error.

6.7.1.4.1 Initial Conditions

Test environment: normal; see clause 4.4.1.

RF channels to be tested for single carrier: B, M and T; see clause 4.8

Base Station RF Bandwidth positions to be tested for multi-carrier: B_RFBW, M_RFBW and T_RFBW; B_RFBW_T’_RFBW and B’_RFBW_T_RFBW in multi-band operation; see subclause 4.8.1;

Refer to annex B for a functional block diagram of the test set-up.

1) Connect the base station antenna connector to the measurement equipment.

6.7.1.4.2 Procedure

1) For a BS declared to be capable of single carrier operation only, set the base station to transmit a signal according to TM1, clause 6.1.1.1, at manufacturer’s declared rated output power, Prated,c.

For a BS declared to be capable of multi-carrier operation, set the BS to transmit according to TM1 on all carriers configured using the applicable test configuration and corresponding power setting specified in sub-clause 4.12.

2) For each carrier, measure the Error Vector Magnitude and frequency error as defined in annex E and the mean power of the signal. The measurement shall be performed on all 15 slots of the frame defined by the Test Model.

3) Using the same setting as in step 1), set the base station to transmit a signal according to TM4, clause 6.1.1.4, with X value equal to 18, and repeat step 2). If the requirement in clause 6.4.4.5 is not fulfilled, decrease the total output power by setting the base station to transmit a signal according to TM4 with X greater than 18, and repeat step 2)

The following test shall be additionally performed if the base station supports HS-PDSCH transmission using 16QAM.

4) Using the same setting as in step 1), set the base station to transmit according to TM5, clause 6.1.1.4A

5) Repeat step 2)

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

6) For multi-band capable BS and single band tests, repeat the steps above per involved band where single band test configuration 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 tests, shall be terminated.

6.7.1.5 Test Requirement

The Error Vector Magnitude for each UTRA carrier and every measured slot shall be less than 17.5% when the base station is transmitting a composite signal using only QPSK modulation and shall be less than 12.5 % when the base station is transmitting a composite signal that includes 16QAM modulation.

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 4.2 and the explanation of how the Minimum Requirement has been relaxed by the Test Tolerance is given in Annex F.

6.7.2 Peak Code Domain Error

6.7.2.1 Definition and applicability

The Peak Code Domain Error is computed by projecting the error vector (as defined in 6.7.1) onto the code domain at a specific spreading factor. The Code Domain Error for every code in the domain is defined as the ratio of the mean power of the projection onto that code, to the mean power of the composite reference waveform. This ratio is expressed in dB. The Peak Code Domain Error is defined as the maximum value for the Code Domain Error for all codes. The measurement interval is one timeslot as defined by the C-PICH (when present), otherwise the measurement interval is one timeslot starting with the beginning of the SCH. See Annex E of this specification for further details.

6.7.2.2 Minimum requirement

The minimum requirement is in TS 25.104[1] clause 6.8.3.

6.7.2.3 Test Purpose

It is the purpose of this test to discover and limit inter-code cross-talk.

6.7.2.4 Method of test

6.7.2.4.1 Initial conditions

Test environment: normal; see clause 4.4.1.

RF channels to be tested for single carrier: B, M and T; see clause 4.8

Base Station RF Bandwidth positions to be tested for multi-carrier: B_RFBW, M_RFBW and T_RFBW, see subclause 4.8.1; Connect the measurement equipment to the BS antenna connector as shown in Figure B.2 annex B.

6.7.2.4.2 Procedure

1) For a BS declared to be capable of single carrier operation only, set the base station to transmit a signal according to TM3, clause 6.1.1.3, at manufacturer’s declared rated output power, Prated,c.

For a BS declared to be capable of multi-carrier operation, set the BS to transmit according to TM3 on all carriers configured using the applicable test configuration and corresponding power setting specified in sub-clause 4.12.

2) Measure Peak code domain error according to annex E. The measurement shall be performed on all 15 slots of the frame defined byTM3. For a BS declared to be capable of multi-carrier operation the measurement is performed on one of the carriers under test.

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

3) 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.

6.7.2.5 Test requirement

The peak code domain error for every measured slot shall not exceed -32 dB at spreading factor 256.

6.7.3 Time alignment error

6.7.3.1 Definition and applicability

This test is only applicable for Node B supporting TX diversity transmission, MIMO, DC-HSDPA, DB-DC-HSDPA, 4C-HSDPA, NC-4C-HSDPA, or 8C-HSDPA, and their combinations.

Frames of the WCDMA 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.

6.7.3.2 Minimum Requirement

The minimum requirement is in TS 25.104 [1] clause 6.8.4.

6.7.3.3 Test Purpose

To verify that the frame timing alignment is within the limits specified in 6.7.3.2.

6.7.3.4 Method of Test

6.7.3.4.1 Initial Conditions

Test environment: normal; see clause 4.4.1.

RF channels to be tested for single carrier: M. See clause 4.8.

Base Station RF Bandwidth positions to be tested for multi-carrier: B_RFBW, M_RFBW and T_RFBW; B_RFBW_T’_RFBW and B’_RFBW_T_RFBW in multi-band operation; see subclause 4.8.1;

Refer to annex B 1.6 for a functional block diagram of the test set-up.

1) Connect base station RF antenna ports to the measurement equipment according to figure B.6.

6.7.3.4.2 Procedure

1) If the BS supports TX diversity or MIMO, set the base station to transmit TM1, clause 6.1.1.1, at manufacturer’s declared rated output power, Prated,c, on one cell using TX diversity or MIMO.

2) Measure the time alignment error between the signals using the P-CPICH on the main antenna port and the CPICH on the diversity antenna port.

3) If the BS supports DC-HSDPA, 4C-HSDPA, NC-4C-HSDPA or 8C-HSDPA set the base station to transmit according to TM1, without using TX diversity or MIMO, on all carriers configured using the applicable test configuration and corresponding power setting specified in sub-clause 4.12.

4) Measure the time alignment error between the signals using the P-CPICH and CPICH signals on the antenna port(s).

5) If the BS supports DB-DC-HSDPA or any of the multi-band 4C-HSDPA or 8C-HSDPA configurations set the base station to transmit TM1 on two carriers belonging to different frequency bands, without using TX diversity or MIMO on any of the carriers.

6) Measure the time alignment error between the signals using the P-CPICH and CPICH signals on the antenna ports.

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

7) 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.

6.7.3.5 Test Requirement

For Tx diversity and MIMO transmission, in the tested cell, TAE shall not exceed 0.35 T_c.

For transmission of multiple cells within a frequency band TAE shall not exceed 0.6 T_c.

For transmission of multiple cells in different frequency bands TAE shall not exceed 5.1 T_c.

6.7.4 Relative Code Domain Error

6.7.4.1 Definition and applicability

The Relative Code Domain Error is computed by projecting the error vector (as defined in 6.7.1) onto the code domain at a specified spreading factor. Only the active code channels in the composite reference waveform are considered for this requirement. The Relative Code Domain Error for every active code is defined as the ratio of the mean power of the error projection onto that code, to the mean power of the active code in the composite reference waveform. This ratio is expressed in dB. The measurement interval is one frame.

The requirement for Relative Code Domain Error is only applicable for 64QAM modulated codes.

See Annex E of this specification for further details.

6.7.4.2 Minimum requirement

The minimum requirement is in TS 25.104[1] clause 6.8.5.1.

6.7.4.3 Test Purpose

It is the purpose of this test to verify that the Relative Code Domain Error is within the limit specified by 6.7.4.2.

6.7.4.4 Method of test

6.7.4.4.1 Initial conditions

Test environment: normal; see clause 4.4.1.

RF channels to be tested for single carrier: B, M and T; see clause 4.8

Base Station RF Bandwidth positions to be tested for multi-carrier: B_RFBW, M_RFBW and T_RFBW, see subclause 4.8.1;

1) Connect the measurement equipment to the BS antenna connector as shown in Figure B.2 annex B.

6.7.4.4.2 Procedure

1) For a BS declared to be capable of single carrier operation only, set the base station to transmit a signal according to TM6, clause 6.1.1.4B, at manufacturer’s declared rated output power, Prated,c.

For a BS declared to be capable of multi-carrier operation, set the BS to transmit according to TM6, clause 6.1.1.4B, on all carriers configured using the applicable test configuration and corresponding power setting specified in sub-clause 4.12.

2) Measure average Relative code domain error according to annex E. The measurement shall be performed over one frame defined by TM6 and averaged as specified in clause E.2.6.3. For a BS declared to be capable of multi-carrier operation the measurement is performed on one of the carriers under test.

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

3) For multi-band capable BS and single band tests, repeat the steps above per involved band where single band test configuration 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.

6.7.4.5 Test requirement

The average Relative Code Domain Error for 64QAM modulated codes shall not exceed -20 dB at spreading factor 16.