Sophia Antipolis, 24 July 2017
Background noise is an issue for telecommunications and needs to be taken into account in terminal design. The higher the intended speech quality as e.g. in wideband or super-wideband telephony, the more critical the terminal optimization is.
To tackle this problem, ETSI’s technical committee on Speech and multimedia Transmission Quality (TC STQ) has just published testing methods to objectively evaluate the performance of super-wideband and fullband terminals for speech communication in the presence of background noise. ETSI TS 103 281 provides testing methods and models to evaluate conversational services for teleconferences and audio-visual applications. It includes state-of-the-art codecs, typical communication packet loss and jitter conditions and recordings in handset, headset, hands-free and car hands-free mode.
To analyse the various parameters influencing speech quality, the new ETSI specification considers the speech quality, the background noise transmission quality and the overall quality. The objective models described in TS 103 281 are based on a huge subjective study conducted with American English, German, and Chinese (Mandarin) speakers. The prediction accuracy of the models is higher than most models currently on the market which is proven by the validation results also provided in the ETSI standard.
“The mobile industry was in demand of these testing methods.” says Hans Wilhelm Gierlich, chairman of the ETSI STQ technical committee.
The STQ committee continues work to develop methodologies, test arrangements and requirements for evaluating the performance of wearable devices for speech communication. The performance evaluation of voice assistant devices e.g. for use in IoT as well as the simulation of room and background noise characteristics in laboratory environments is progressing, new specifications are expected in 2018. The group is also working on a specification aimed at improving listening quality for people with impaired hearing. The specification will define requirements and measurement methods to assess the impact of different transmission impairments on intelligibility as well as a model to assess speech intelligibility objectively. It is expected to be published later this year.