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TU Berlin

Inhalt des Dokuments

Speech Quality per Call


Modeling overall speech quality in telephone conversations

Motivation & Project Description

  • Speech quality of mobile telephone or VoIP networks varies with time due to changes in transmission channel characteristics.
  • Motivation: In order to plan and monitor telephone networks with time-varying quality, a model has to be established, that can quantify user’s final judgments immediately after finishing a call.

    • Experiments have been conducted to obtain quality ratings “per call” and those of short-term speech samples.
    • A model was developed, that incorporates the results of the experiments.
    • The model was evaluated with independent rating experiments.


  • The model successfully predicts quality “per call” out of short-term quality estimates obtained by an instrumental method.
  • Standardization: The method was approved by the ETSI STQ mobile group (TR 102 506).
  • Scientific publications
Time Frame:

01/2007 - 04/2007
T-labs Team Members:

S. Möller, B. Weiss


SwissQual AG, Solothurn, Switzerland
Ericsson L.M., Sweden
Funding by:
T-Mobile, Germany
E-Plus, Germany
See list of publications by Möller and Weiss

Zusatzinformationen / Extras


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