81.1 Mobile-to-fixed Audio Quality Measurement with CallGenerator

This section describes the AQM setup where a CallGenerator acts as the receiver of AQM calls. It is referred to by the M2F DL + UL option in the AQM Measurement activity of the Service Control script (see section " AQM Measurement").
The computation of AQM scores is done in the AQM modules: one connected to the phone and to the PC, handling the downlink; and one housed in the CallGenerator, taking care of the uplink. These modules contain DSP hardware. The downlink AQM module can optionally be mounted along with the phone in an equipment case.
Below is an overview of the measurement configuration.

The measurement procedure can be summarized as follows:

The speech segments to be used as references are loaded into the AQM modules and into the test phone.

The phone calls the CallGenerator and plays the reference sentences. The CallGenerator responds by playing the same reference sentences.

The received (degraded) signals at either end are forwarded to the respective AQM modules, where the signals are compared with the originals, yielding uplink and downlink PESQ scores. The AQM modules also record a number of further audio quality measurements such as echo delay, echo attenuation, and volume. See Information Elements and Events, section "Information Element Table".

The downlink AQM data is written to regular TEMS Investigation logfiles. The uplink AQM data is stored in XML files.

To merge uplink AQM data into the logfiles, the logfile export function is used. See section "Merging Uplink AQM Data into Logfiles".