6.5 Adjacent channel power

3GPP51.021Base Station System (BSS) equipment specificationRadio aspectsRelease 17TS

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

The modulation, wideband noise and power level switching spectra can produce significant interference in the relevant TX and adjacent bands. The requirements for adjacent channel emissions are tested in two separate tests which intend to measure different sources of emission:

1) continuous modulation spectrum and wideband noise;

2) switching transients spectrum.

NOTE: Both requirements must be met, irrespective of the source of the emission at any particular frequency.

6.5.1 Spectrum due to modulation and wideband noise

6.5.1.1 Test purpose

To verify that the output RF spectrum due to modulation and wideband noise does not exceed the specified levels for an individual transceiver.

6.5.1.2 Test case

The system under test shall be tested with one TRX active or with the BTS equipped with only one TRX, at three frequencies (first at RF channel B, second at RF channel M and third at RF channel T). Slow frequency hopping shall be disabled.

a) All time slots shall be set up to transmit full power GMSK modulated with a pseudo‑random bit sequence of encrypted bits apart from time slot 0 which shall be set up to transmit at full power but may be modulated with normal BCCH data. The pseudo‑random bit sequence may be generated by another pseudo‑random bit sequence inserted before channel encoding in the BSS.

b) The power level (as used in table 6.5-1) shall be measured using the method of subclause 6.3 for each power step to be tested.

c) Using a filter and video bandwidth of 30 kHz the power shall be measured at the antenna connector on the carrier frequency. The measurement shall be gated over 50 ‑ 90 % of the useful part of the time slot excluding midamble, and the measured value over this part of the burst shall be averaged. The averaging shall be over at least 200 time slots and only the active burst shall be included in the averaging process. The test is performed on one timeslot and not on timeslot 0.

d) Step c) shall be repeated with the following offsets above and below the carrier frequency:

in case of BTS not belonging to a multicarrier BTS class:

– 100 kHz, 200 kHz, 250 kHz, 400 kHz; and

– 600 kHz to 1 800 kHz in steps of 200 kHz.

in case of BTS belonging to a multicarrier BTS class:

– 100 kHz, 200 kHz, 250 kHz, 400 kHz; and

– 600 kHz up to and including 1 600 kHz in steps of 200 kHz.

e) With all time slots at the same power level, step c) and d) shall be repeated for all static power levels specified for the equipment (subclause 6.3).

f) With a filter and video bandwidth of 100 kHz and all time slots active, the power shall be measured at the antenna connector for frequency offsets beyond 1800 kHz up to 2 MHz outside either side of the relevant TX band in case of BTS not belonging to a multicarrier BTS class. In case of BTS belonging to a multicarrier BTS class the power shall also be measured at the frequency offset of 1.8 MHz. This test shall be made in a frequency scan mode, with a minimum sweep time of 75 ms and averaged over 200 sweeps.

g) With all time slots at the same power level, step f) shall be repeated for all static power levels specified for the equipment (subclause 6.3).

h) If the TRX supports QPSK, AQPSK, 8-PSK, 16-QAM or 32-QAM modulation, step a) to g) shall be repeated with all time slots set up to transmit with the respective modulation apart from timeslot 0 which may be modulated with normal BCCH data.

For a multicarrier BTS, the test methods and conditions in this subclause apply for configurations with one carrier active. For BTS configurations with more than one carrier active, the test in subclause 6.12 shall be performed.

6.5.1.3 Void

6.5.1.4 Conformance requirement

Test Environment

Normal

6.5.1.4.1 Normal BTS Minmimum requirement

The test shall be performed for one TRX. In case of a multicarrier BTS the test is performed for each transmitting antenna connector.

For each static power step, the power measured in steps d) to g) of the test cases shall not exceed the limits shown in table 6.5-1 for the power level measured in step b), except where one or more of the following exceptions and minimum measurement levels applies:

1) For a GSM 400, GSM 900, ER-GSM 900, GSM 850, MXM 850 or GSM 700 BTS, if the limit according to table 6.5-1 is below ‑65 dBm, a value of ‑65 dBm shall be used instead.

2) For a DCS 1800, PCS 1900 or MXM 1900 BTS, if the limit according to table 6.5-1 is below ‑57 dBm, a value of ‑57 dBm shall be used instead.

3) In the combined range 600 kHz to 6 MHz above and below the carrier frequency, in up to three bands of 200 kHz width centred on a frequency which is an integer multiple of 200 kHz, exceptions at up to ‑36 dBm are allowed.

4) Above 6 MHz offset from the carrier frequency, in up to 12 bands of 200 kHz width centred on a frequency which is an integer multiple of 200 kHz, exceptions at up to ‑36 dBm are allowed.

Table 6.5-1: Continuous modulation spectrum ‑ maximum limits for BTS

Power

level

Maximum relative level (dB) at specified carrier offsets (kHz),

using specified measurement (filter)bandwidths (kHz):

(dBm)

100

200

250

400

600 to

< 1 200

1 200 to

< 1 800

1 800 to

< 6 000

>6000 **

as measured in step b)

Measurement (filter)bandwidth;

30 kHz

Measurement (filter)

bandwidth; 100 kHz

Case 1

 43

+0,5

‑30

‑33

‑60*

‑70

‑73

‑75

‑80

+0,5

‑30

‑33

‑60*

‑68

‑71

‑73

‑80

+0,5

‑30

‑33

‑60*

‑66

‑69

‑71

‑80

+0,5

‑30

‑33

‑60*

‑64

‑67

‑69

‑80

+0,5

‑30

‑33

‑60*

‑62

‑65

‑67

‑80

 33

+0,5

‑30

‑33

‑60*

‑60

‑63

‑65

‑80

* For equipment supporting QPSK, AQPSK, 8-PSK, 16-QAM or 32-QAM, at normal symbol rate, the requirement at these modulations is -56 dB.

** For equipment belonging to a multicarrier BTS class, the requirement also applies for the frequency offset of 6 MHz.

The requirements are specified, depending on symbol-rate and pulse-shaping filter used:

Case 1: Normal symbol rate using linearised GMSK pulse-shaping filter and higher symbol rate using spectrally narrow pulse shaping filter

The spectrally narrow pulse shaping filter in Case 1 and the spectrally wide pulse shaping filter in Case 2 are in this specification referred to as narrow and wide pulse shaping filter respectively. The limit values in table 6.5-1, at the listed offsets from carrier frequency (kHz), are the ratio of the measured power to the measured power in step c) for the same static power step.

Table 6.5-1 provides requirements at discrete power levels. For powers between those specified, linear interpolation should be applied.

6.5.1.4.2 Multicarrier BTS Minimum requirement

The test shall be performed with one carrier active for each transmitting antenna connector.

1) Exceptions at up to ‑36 dBm, ‑42 dBm and ‑50 dBm are allowed for the Wide Area, Medium Range and Local Area multicarrier BTS classes, respectively. The measurement conditions as specified in clause 6.12.4 for exceptions apply. The number of allowable exceptions for the frequency offset range from 600 kHz up to 10 MHz outside the relevant transmit band is equal to 18 as defined in clause 6.12.4 for N=1.

2) For all frequency bands, if the limit according to table 6.5-1 is below ‑47 dBm, ‑53 dBm and ‑61 dBm, for the Wide Area, Medium Range and Local Area multicarrier BTS class, respectively, this value shall be used instead.

6.5.1.4.3 Micro and Pico-BTS Minimum requirement

The test shall be performed for one TRX.

For each static power step, the power measures in steps d) and e) of the test case shall not exceed the limits shown in table 6.5-1 for the power level measured in step b), except where one or more of the micro or pico-BTS exceptions and minimum measurement levels applies.

For each static power step, the ratio of the power measured in steps f) and g) of the test case to the power measured in step c) for the same static power step shall not exceed the limits specified in table 6.5-2 for GSM 900, ER-GSM 900, GSM 850, MXM 850 and GSM 700 and table 6.5-3 for DCS 1800, PCS 1900 and MXM 1900 systems, except where one or more of the micro or pico-BTS exceptions and minimum measurement levels applies.

Table 6.5-2: Continuous modulation spectrum – maximum limits for GSM 900, ER-GSM 900,
GSM 850, MXM 850 and GSM 700 Micro and Pico-BTS

Power Class		Maximum relative level (dB) at specified carrier offsets (kHz), using specified measurement (filter)bandwidths (kHz):
			1 800 to < 6 000	> 6 000
			Measurement (filter) bandwidth; 100kHz
M1 to M3	Case 1		-70	-70
P1	Case 1		-70	-80

Table 6.5-3: Continuous modulation spectrum – maximum limits for DCS 1800, PCS 1900
and MXM 1900 Micro and Pico-BTS

Power Class		Maximum relative level (dB) at specified carrier offsets (kHz), using specified measurement (filter)bandwidths (kHz):
		1 800 to < 6 000	> 6 000
		Measurement (filter) bandwidth; 100kHz
M1 to M3	Case 1	-76	-76
DCS 1800 P1	Case 1	-76	-80
PCS 1900 and MXM 1900 P1	Case 1	-76	-76

The following exceptions and minimum measurement levels shall apply for the micro and pico‑BTS.

1) In the combined range 600 kHz to 6 MHz above and below the carrier frequency, in up to three bands of 200 kHz width centred on a frequency which is an integer multiple of 200 kHz, exceptions at up to ‑36 dBm are allowed.

2) Above 6 MHz offset from the carrier frequency, in up to 12 bands of 200 kHz width centred on a frequency which is an integer multiple of 200 kHz, exceptions at up to ‑36 dBm are allowed.

3) If the limit as specified above is below the values in table 6.5-4, then the values in table 6.5-4 shall be used instead.

Table 6.5-4: Continuous modulation spectrum ‑ minimum levels for micro and pico‑BTS

Power Class	Maximum spectrum due to modulation and noise in 100 kHz
	GSM 900, ER-GSM 900, GSM 850, MXM 850 and GSM 700 (dBm)	DCS 1800, PCS 1900 and MXM 1900 (dBm)
M1	‑59	‑57
M2	‑64	‑62
M3	‑69	‑67
P1	-68	-65

VAMOS mode is not applicable to pico BTS.

The test shall be repeated until each TRX in the configuration has been tested. The minimum conformance requirement shall be met for each TRX. For a multicarrier BTS, the test shall be repeated for each transmitting antenna connector.

6.5.1.5 Requirement reference

3GPP TS 45.005 subclause 4.2.1.

6.5.2 Switching transients spectrum

6.5.2.1 Test purpose

To verify that the output RF spectrum due to switching transients does not exceed the specified limits.

6.5.2.2 Test case

The Manufacturer shall declare how many TRXs the BSS supports:

1 TRX: The TRX shall be tested at B, M and T.

2 TRX: One shall be configured to support the BCCH and the second TRX shall be activated and tested at B, M and T.

3 TRX: One shall be configured to support the BCCH and the other two shall be activated and tested. Tests shall be performed on B, M and T and both TRXs shall be tested on at least one frequency.

4 TRX or more: One shall be configured to support the BCCH and three TRXs shall be tested, one on B, one on M and one on T.

For a multicarrier BTS, the test is performed for a single active carrier at B, M and T for each antenna port, transmitting at declared maximum power.

If the TRX supporting the BCCH is physically different from the remaining TRX(s), it shall also be tested on B, M and T.

a) All active time slots shall be GMSK, 8-PSK, QPSK, AQPSK, 16-QAM or 32-QAM modulated with a pseudo‑random bit sequence apart from time slot 0 of the TRX supporting the BCCH which may be modulated with normal data. The power shall be measured at the offsets listed below from one of the carrier frequencies in the configuration with the test equipment parameters below. The reference power for relative measurements is the power measured in a bandwidth of at least 300 kHz for the TRX under test for the time slot in this test with the highest power.

Resolution bandwidth: 30 kHz

Video bandwidth: 100 kHz

Zero frequency scan

Peak hold enabled

The following offsets from the carrier frequency shall be used:

400 kHz, 600 kHz, 1200 kHz and 1800 kHz.

b) All timeslots of the TRX or TRXs under test shall be activated at the highest level of static power control and the power measured as described in step a). If synthesizer SFH is supported, the test shall be repeated for the TRX or TRXs which are activated and which do not support the BCCH, with them hopping between B, M and T.

c) All timeslots of the TRX or TRXs under test shall be activated at the lowest level of static power control and the power measured as described in step a). If synthesizer SFH is supported, the test shall be repeated for the TRX or TRXs which are activated and which do not support the BCCH, with them hopping between B, M and T.

d) Any active TRX which does not support the BCCH shall be configured with alternate timeslots active at the highest level of static power control and the remaining timeslots idle as illustrated in figure 6.5-2 and the power measured as described in step a).

e) Any active TRX which does not support the BCCH shall be configured with alternate timeslots active at the lowest level of static power control and the remaining timeslots idle as illustrated in figure 6.5-2 and the power measured as described in step a).

f) If the BSS supports dynamic downlink power control, any active TRX which does not support the BCCH shall be configured with transitions between timeslots active at the highest level of static power control and timeslots active at the lowest available level of dynamic power control and idle timeslots, as illustrated in figure 6.5-1 and the power measured as described in step a).

NOTE: Pdmin = The lowest dynamic power step measured in subclause 6.3.

Figure 6.5-1: Power/time slot configuration (RF power control)

Figure 6.5-2: Power/time slot configuration (no RF power control)

6.5.2.3 Void

6.5.2.4 Conformance requirement

Test environment:

Normal.

Minimum requirement

The test shall be repeated until all the TRXs specified to be tested have each been tested on the B, M and T.

The power measured shall not exceed the limits shown in table 6.5-5, or ‑36 dBm, whichever value is highest.

For multicarrier BTS, the power measured shall not exceed the limits shown in table 6.5-5, or ‑36 dBm, whichever value is less stringent.

Table 6.5-5: Switching transients spectrum ‑ maximum limits

Offset (kHz):	Power (dBc): GSM 400, GSM 900, ER-GSM 900, GSM 850, MXM 850 and GSM 700 (GMSK)	Power (dBc): GSM 400, GSM 900, ER-GSM 900, GSM 850, MXM 850 and GSM 700 (8-PSK, QPSK, AQPSK, 16-QAM, 32-QAM)	Power (dBc) DCS 1800, PCS 1900 and MXM 1900 (GMSK)	Power (dBc) DCS 1800, PCS 1900 and MXM 1900 (8-PSK, QPSK, AQPSK, 16-QAM, 32-QAM)
400	‑57	‑52	‑50	‑50
600	‑67	‑62	‑58	‑58
1200	‑74	‑74	‑66	‑66
1800	‑74	‑74	‑66	‑66

6.5.2.5 Requirement reference

3GPP TS 45.005 subclause 4.2.2.