5.1.5 Test setup for quality in the presence of ambient noise measurements

26.1323GPPRelease 18Speech and video telephony terminal acoustic test specificationTS

5.1.5.1 Handset

The setup for simulating realistic ambient noises and the positioning of the HATS in a lab-type environment is described in ETSI ES 202 396‑1 [35].

ETSI ES 202 396‑1 [35] contains a description of the recording arrangement for realistic ambient noises, a description of the setup for a loudspeaker arrangement suitable to simulate an ambient noise field in a lab-type environment and a database of realistic ambient noises, part of which is used for testing the terminal performance with a variety of conditions.

Two different methods (Method 1 and Method 2) for equalization and calibration of the loudspeakers are allowed and specified below. The method selected for the test setup (Method 1 or Method 2) shall be reported. Method 2 is preferred over Method 1 due to the improved cross-lab reproduction accuracy reported in clause 5 of TR 26.921 [52].

Method 1:

The equalization and calibration procedure for this test setup given in ETSI ES 202 396‑1 [35] shall be used.

This method works semi-automated and requires manual adjustment steps during the equalization procedure. The equalization is carried out in the frequency range between 50 Hz and 10 kHz.

Method 2:

The equalization and calibration procedure for this test setup given in Clause 7 of ETSI TS 103 224 [43] shall be used. During the equalization procedure, a so-called “reference sound” is needed for verification purposes. In this case, the noise type “TrainStation_bin” of Clause 8 of ETSI TS 103 224 [43] (time range 15.0 to 22.5s) shall be used.

NOTE: Clause 7 of ETSI TS 103 224 [43] describes recording and reproduction arrangement for an (almost) arbitrary number of microphones and loudspeakers. In order to produce ambient noise field compatible to Method 1, a flexible setup with two recording/playback channels (binaural noise signals) and a 4.0 (or 4.1) loudspeaker configuration is used.

In contrast to the Method 1 according to ETSI ES 202 396‑1 [35], a fully automated equalization procedure including reduction of cross-talk is provided by Method 2. The equalization is carried out in the frequency range between 50 Hz and 20 kHz.

5.1.5.2 Hand-held hands-free

For hand-held hands-free UE, the test setup for simulating realistic ambient noises and the position of the HATS in a lab-type environment is described in ETSI TS 103 224 [43]. The setup in ETSI ES 202 396‑1 [35] may also be used as described below.

ETSI TS 103 224 [43] contains a description of the recording arrangement for realistic ambient noises, a description of the setup for loudspeaker arrangement suitable to simulate an ambient noise field in a lab type environment, and a database of realistic ambient noises, part of which is used for testing the hands-free UE performance. Note that TS 103 224 [43] provides improved reproduction accuracy in terms of frequency and spatial characteristics, and so is recommended for testing hands-free UE. The equalization setup and the test setup is shown in Figs. 15a1 – 15a5.

Figure 15a1: Equalization using the TS 103 224 method, the circle indicates the microphone array used for the equalization

Figure 15a2: Measurements using the TS 103 224 method

Figure 15a3: Detailed positioning of the hands-free UE

The setup in ETSI ES 202 396‑1 [35] may be used for testing hands-free UE, provided that after the equalization and calibration procedure for handset UE are completed, the HATS is removed from the calibration location in the test room, and the hands-free UE under test is placed at the calibration location. The HATS is then placed in a location with respect to the hands-free UE under test, as described in Clause 5.1.3.2 and 5.1.3.3. The equalization setup and the test setup is shown in Figs. 15a4 and 15a5. Each ambient noise in the database of ETSI TS 103 224 [43] is available in a version compatible with reproduction using ETSI ES 202 396‑1 [35].

Figure 15a4: Equalization using the ES 202 396-1 method

Figure 15a5: Measurements using the ES 202 396-1 method