Finally a comprehensive overview of speech quality in Vo IP from the user’s perspective!
Speech Quality of Vo IP is an essential guide to assessing the speech quality of Vo IP networks, whilst addressing the implications for the design of Vo IP networks and systems. This book bridges the gap between the technical network-world and the psychoacoustic world of quality perception. Alexander Raake’s unique perspective combines awareness of the technical characteristics of Vo IP networks and original research concerning the perception of speech transmitted across them.
Starting from the network designer’s point of view, the different characteristics of the network are addressed, and then linked to features perceived by users. This book provides an overview of the available knowledge on the principal, relevant aspects of speech and speech quality perception, of speech quality assessment, and of transmission properties of telephone and Vo IP networks, and of the related perceptual features and resulting speech quality. Discussing new research into the specific time-varying degradations Vo IP brings along, but also the considerable potential of quality improvement to be achieved with wideband speech transmission, Alexander Raake demonstrates how network and service characteristics impact on the users perception of quality.
Speech Quality of Vo IP:
* Offers an insight into speech quality of Vo IP from a user’s perspective.
* Presents an overview of different modelling approaches and a parametric network-planning model for quality prediction in Vo IP networks.
* Draws on innovative new research on the quality degradation characteristic of Vo IP.
* Explains in detail how telephone speech quality can be greatly enhanced with Vo IP’s wideband speech transmission capability.
* Assesses the vast collection of references into the technical and scientific literature related to Vo IP quality.
* Illustrates concepts throughout with mathematical models, algorithms and simulations.
Speech Quality of Vo IP is the definitive guide for researchers, engineers and network planners working in the field of Vo IP, Quality of Service, and speech communication processing in telecommunications. Advanced undergraduate and graduate students on telecommunication and networking courses will also find this text an invaluable resource.
Tabela de Conteúdo
Preface.
List of Abbreviations.
Introduction.
1 Speech Quality in Telephony.
1.1 Speech.
1.2 Speech Quality.
2 Speech Quality Measurement Methods.
2.1 Auditory Methods.
2.2 Instrumental Methods.
2.3 Speech Quality Measurement Methods: Summary.
3 Quality Elements and Quality Features of Vo IP.
3.1 Speech Transmission Using Internet Protocol.
3.2 Overview of Quality Elements.
3.3 Quality Elements and Related Features.
3.4 Quality Dimensions.
3.5 Combined Elements and Combined Features.
3.6 Listening and Conversational Features.
3.7 Desired Nature.
3.8 Open Questions.
3.9 From Elements to Features: Modeling Vo IP Speech Quality.
3.10 Quality Elements and Quality Features of Vo IP: Summary.
4 Time-Varying Distortion: Quality Features and
Modeling.
4.1 Microscopic Loss Behavior.
4.2 Macroscopic Loss Behavior.
4.3 Interactivity.
4.4 Packet Loss and Combined Impairments.
4.5 Time-Varying Distortion: Summary.
5 Wideband Speech, Linear and Non Linear Distortion: Quality
Features and Modeling.
5.1 Wideband Speech: Improvement Over Narrowband.
5.2 Bandpass-Filtered Speech.
5.3 Wideband Codecs.
5.4 Desired Nature.
6 From Elements to Features: Extensions of the
E-model.
6.1 E-model: Packet Loss.
6.2 E-model: Additivity.
6.3 E-model: Wideband, Linear and Non-Linear Distortion.
7 Summary and Conclusions.
8 Outlook.
A Aspects of a Parametric Description of Time-Varying
Distortion.
B Simulation of Quality Elements.
C Frequency Responses.
D Test Data Normalization and Transformation.
E E-model Algorithm.
F Interactive Short Conversation Test Scenarios
(i SCTs).
G Auditory Test Settings and Results.
H Modeling Details.
I Glossary.
Bibliography.
Index.
Sobre o autor
Alexander Raake is Senior Scientist at Deutsche Telekom Laboratories, Berlin. Alexander has worked in the field of Vo IP quality and related topics for almost seven years. Current research topics include service personalization, user expectation and the quality and usability of Vo IP-based speech transmission systems, and virtual environments for multi-party communication and multi-modal systems. Since 1999 Alexander has participated in the standardization activities of the International Telecommunication Union (ITU-T) on transmission performance of telephone networks and terminals.
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