F.1 General

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

The annex describes various procedures for BS OTA TRP measurements. These procedures can provide either an accurate or an over-estimate of TRP values. The procedures for an accurate estimate can be applied to all TRP requirements. However, if a TRP requirement does not need accurate TRP estimate then the procedures for over-estimate of TRP may be used in order to have a reasonable OTA test time. Pre-scan does not provide an accurate TRP estimate or over-estimate of TRP. Pre-scan is a fast but coarse method that is used to identify the spurious emission frequencies with emission power as described in annex F.13. A sequential measurement is then made at the emission frequencies, to assess the TRP as described in annex F.2 to annex F.9.

When making TRP measurements the alignment between EUT and measurement antenna is important to achieve expected measurement uncertainty;

1. The measurement antenna needs to be aligned tangential to the measurement surface forming a sphere around the EUT, in order to measure the TRP properly.

2. Test methods described in clauses F.5.1, F.5.2, F.10, F.11 and F.12 require angular alignment between the selected measurement grid and EUT radiation pattern in order to measure peak values in the main beams. Angular misalignment can lead to differences in the actual and measured angular positions of the intended maximum EIRP.

3. Test methods described in clause F.5.3, F.6 and F.9 are designed to be independent of rotations of the angular grid, and hence angular alignment between the measurement grid and EUT is not needed.