Predicting speech quality of telecommunications systems in a quality differentiated market

Performance factors such as quality are important in a competitive telecommunications market where price differentials have been minimised. An important aspect of service performance is speech quality. Efficient network design and service delivery is facilitated by objective assessment of performance as perceived by customers. Such assessment is not possible with conventional engineering measures if the system under test includes complex components such as data reduction. A new generation of objective assessment techniques is under development at BT Labs, using models of the human senses. In this paper, the principal applications of these techniques in intrusive and nonintrusive quality assessment are described. Future trends in objective quality assessment are discussed and the concepts of subjective testing, user expectation and multi-sensory perceptual analysis are introduced