6.7.2 OTA occupied bandwidth

37.145-23GPPActive Antenna System (AAS) Base Station (BS) conformance testingPart 2: radiated conformance testingRelease 17TS

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

6.7.2.1 Definition and applicability

The OTA occupied bandwidth is the width of a frequency band such that, below the lower and above the upper frequency limits, the mean powers emitted are each equal to a specified percentage /2 of the total mean transmitted power. See also recommendation ITU-R SM.328 [14].

The value of /2 shall be taken as 0.5%.

The OTA occupied bandwidth requirement applies during the transmitter ON period for a single transmitted carrier. The minimum requirement below may be applied regionally. There may also be regional requirements to declare the OTA occupied bandwidth according to the definition in the present clause.

The OTA occupied bandwidth is defined as a directional requirement and shall be met in the manufacturer’s declared OTA coverage range at the RIB.

6.7.2.2 Minimum Requirement

For AAS BS in MSR operation the minimum requirement is defined in TS 37.105 [6], clause 9.7.2.2.

For AAS BS in single RAT UTRA operation the minimum requirement is defined in TS 37.105 [6], clause 9.7.2.3.

For AAS BS in single RAT E-UTRA operation the minimum requirement is defined in TS 37.105 [6], clause 9.7.2.4.

6.7.2.3 Test purpose

The test purpose is to verify that the emission at the RIB does not occupy an excessive bandwidth for the service to be provided and is, therefore, not likely to create interference to other users of the spectrum beyond undue limits.

6.7.2.4 Method of test

6.7.2.4.1 Initial conditions

6.7.2.4.1.1 General test conditions

Test environment:

– normal; see annex G.2.

RF channels to be tested:

– M; see clause 4.12.1.

Aggregated Channel Bandwidth positions to be tested for contiguous carrier aggregation: M_{BW Channel CA}

Directions to be tested:

– The reference beam direction pair (see table 4.10-1, D9.7).

6.7.2.4.1.2 UTRA FDD

– Set the AAS BS to transmit a signal in accordance to TM1in clause 4.12.2 at manufacturers declared rated carrier EIRP (P_rated,c,EIRP).

6.7.2.4.1.3 E-UTRA and NR

– Aggregated Channel Bandwidth positions to be tested for contiguous carrier aggregation:

– B_{BW Channel CA}, M_{BW Channel CA} and T_{BW Channel CA}.

– For a AAS BS declared to be capable of single carrier operation, start transmission according to E- TM1.1 or N- TM1.1, clause 4.12.2 at manufacturers declared rated carrierEIRP (P_rated,c,EIRP).

– For a AAS BS declared to be capble of contiguas carrier aggregation operation, set the base station to transmit according to E-TM1.1 or N- TM1.1, on all carriers configured using the applicable test configuration and corresponding power setting specified in clause 5

– For an AAS BS declared to be capable of multi-carrier and/or CA operation use the applicable test signal configuration and corresponding power setting specified in clause 4.11.

6.7.2.4.2 Procedure

1) Place the AAS BS at the positioner.

2) Align the manufacturer declared coordinate system orientation (see table 4.10-1, D9.2) of the AAS BS with the test system.

3) Orient the positioner (and BS) in order that the direction to be tested aligns with the test antenna.

4) Configure the beam peak direction of the AAS BS according to the declared beam direction pair.

5) Set the AAS BS to transmit signal.

6) For UTRA FDD, measure the spectrum of the transmitted signal across a span of 10 MHz, based on an occupied bandwidth requirement of 5 MHz. The selected resolution bandwidth (RBW) filter of the analyser shall be 30 kHz or less. The spectrum shall be measured at 400 or more points across the measurement span.

For E-UTRA and NR measure the spectrum emission of the transmitted signal using at least the number of measurement points, and across a span, as listed in table 6.7.2.4.2-1. The selected resolution bandwidth (RBW) filter of the analyser shall be 30 kHz or less.

NOTE: The detection mode of the spectrum analyzer will not have any effect on the result if the statistical properties of the out-of-OBW power are the same as those of the inside-OBW power. Both are expected to have the Rayleigh distribution of the amplitude of Gaussian noise. In any case where the statistics are not the same, though, the detection mode is power responding. There are at least two ways to be power responding. The spectrum analyser can be set to "sample" detection, with its video bandwidth setting at least three times its RBW setting. Or the analyser may be set to respond to the average of the power (root-mean-square of the voltage) across the measurement cell.

Table 6.7.2.4.2-1: Span and number of measurement points for OBW measurements for FR1

Bandwidth	BS channel bandwidth BW_Channel (MHz)					Aggregated BS channel bandwidth BW_{Channel_CA} (MHz)
	5	10	15	20	> 20	> 20
Span (MHz)	10	20	30	40
Minimum number of measurement points	400	400	400	400

7) Compute the total of the EIRP, P0, (in power units, not decibel units) of all the measurement cells in the measurement span. Compute P1, the EIRP outside the occupied bandwidth on each side. P1 is half of the total EIRP outside the bandwidth. P1 is half of (100 % – (occupied percentage)) of P0. For the occupied percentage of 99 %, P1 is 0.005 times P0. Measure the EIRP for any two orthogonal polarizations (denoted p1 and p2) and calculate total radiated transmit power for particular beam direction pair as EIRP = EIRP_p1 + EIRP_p2.

8) Determine the lowest frequency, f1, for which the sum of all EIRP in the measurement cells from the beginning of the span to f1 exceeds P1.

9) Determine the highest frequency, f2, for which the sum of all EIRP in the measurement cells from the end of the span to f2 exceeds P1.

10) Compute the OTA occupied bandwidth as f2 – f1.

In addition, for multi-band RIB(s), the following steps shall apply:

11) For multi-band RIBs and single band tests, repeat the steps 6) – 10) above per involved band where single band test configurations and test models shall apply with no carriers activated in the other band.

6.7.2.5 Test Requirement

6.7.2.5.1 MSR

The OTA occupied bandwidth of a single carrier shall be less than the values listed in table 6.7.2.5.1-1. In addition, for E‑UTRA/NR intra-band contiguous carrier aggregation, test requirement in clause 6.6.1.5 of TS 36.141 [12] applies for the E-UTRA/NR component carriers that are aggregated.

Table 6.7.2.5.1-1: OTA Occupied bandwidth

RAT	OTA Occupied bandwidth limit
E-UTRA/NR	BW_Channel
UTRA FDD	5 MHz

6.7.2.5.2 UTRA FDD

The OTA occupied bandwidth shall be less than 5 MHz based on a chip rate of 3,84 Mcps.

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 4.1.2 and the explanation of how the Minimum Requirement has been relaxed by the Test Tolerance is given in annex C.

6.7.2.5.3 E-UTRA

The OTA occupied bandwidth for each E-UTRA carrier shall be less than the channel bandwidth. For contiguous CA, the occupied bandwidth shall be less than or equal to the Aggregated Channel Bandwidth as defined in TS 36.141 [12] clause 5.6.