Speech Quality Estimation Of Voice Over Internet Protocol

Telecommunications technologies are evolving at a rapid pace. The old Public Switched Telephone Network (PSTN) is being replaced with wireless and voice over IP (VoIP) systems. This requires the service providers to offer their services on competitive prices, on one hand, and to ensure the interoperability of their services over hetero- geneous networks on the other. Added to this is the challenge of keeping up with the expectations of the clientele as regards quality of service (QoS). Thus to enable the successful deployment and functioning of a telecommunications network, it is equally important to estimate the speech quality as it may be perceived by the humans. The goal of this research was to derive superior non-intrusive speech quality esti- mation models. Model superiority was sought in a multi-objective sense: 1) enhance- ment of prediction accuracy of the derived models as compared to the previous ones. 2) model simplicity or parsimony was desired as it may enhance the computational efficiency. In this research this is achieved by employing a novel approach based on Genetic Programming (GP).

Finally a comprehensive overview of speech quality in VoIP from the user's perspective! Speech Quality of VoIP is an essential guide to assessing the speech quality of VoIP networks, whilst addressing the implications for the design of VoIP 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 VoIP 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 VoIP networks, and of the related perceptual features and resulting speech quality. Discussing new research into the specific time-varying degradations VoIP 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 VoIP: Offers an insight into speech quality of VoIP from a user's perspective. Presents an overview of different modelling approaches and a parametric network-planning model for quality prediction in VoIP networks. Draws on innovative new research on the quality degradation characteristic of VoIP. Explains in detail how telephone speech quality can be greatly enhanced with VoIP’s wideband speech transmission capability. Assesses the vast collection of references into the technical and scientific literature related to VoIP quality. Illustrates concepts throughout with mathematical models, algorithms and simulations. Speech Quality of VoIP is the definitive guide for researchers, engineers and network planners working in the field of VoIP, 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.

Seventeen articles, all written by specialists in industry (most, like the editor, work for BTexact Technologies), offer a broad treatment of Voice over IP, or VoIP. Among the topics are voice quality, access, telephony solutions at the customer level, international standards, SS7 over IP, gateways and the Megaco architecture, bearer-independent call control, numbering and naming, multimedia with H.323, and clearinghouses and open settlement protocol. Annotation copyrighted by Book News, Inc., Portland, OR

This book presents a review of the latest advances in speech and video compression, computer networking protocols, the assessment and monitoring of VoIP quality, and next generation network architectures for multimedia services. The book also concludes with three case studies, each presenting easy-to-follow step-by-step instructions together with challenging hands-on exercises. Features: provides illustrative worked examples and end-of-chapter problems; examines speech and video compression techniques, together with speech and video compression standards; describes the media transport protocols RTP and RTCP, as well as the VoIP signalling protocols SIP and SDP; discusses the concepts of VoIP quality of service and quality of experience; reviews next-generation networks based on the IP multimedia subsystem and mobile VoIP; presents case studies on building a VoIP system based on Asterisk, setting up a mobile VoIP system based on Open IMS and Android mobile, and analysing VoIP protocols and quality.

Voice over Internet Protocol (VoIP) is an active area of research in the world ofcommunication. The high revenue made by the telecommunication companies is amotivation to develop solutions that transmit voice over other media rather thanthe traditional, circuit switching network. However, while IP networks can carry data traffic very well due to their besteffortnature, they are not designed to carry real-time applications such as voice. As such several degradations can happen to the speech signal before it reaches itsdestination. Therefore, it is important for legal, commercial, and technical reasonsto measure the quality of VoIP applications accurately and non-intrusively. Several methods were proposed to measure the speech quality: some of thesemethods are subjective, others are intrusive-based while others are non-intrusive. One of the non-intrusive methods for measuring the speech quality is the E-modelstandardised by the International Telecommunication Union-Telecommunication StandardisationSector (ITU-T). Although the E-model is a non-intrusive method for measuring the speech quality, but it depends on the time-consuming, expensive and hard to conduct subjectivetests to calibrate its parameters, consequently it is applicable to a limited numberof conditions and speech coders. Also, it is less accurate than the intrusive methodssuch as Perceptual Evaluation of Speech Quality (PESQ) because it does not considerthe contents of the received signal. In this thesis an approach to extend the E-model based on PESQ is proposed. Using this method the E-model can be extended to new network conditions andapplied to new speech coders without the need for the subjective tests. The modifiedE-model calibrated using PESQ is compared with the E-model calibrated usingiiisubjective tests to prove its effectiveness. During the above extension the relation between quality estimation using theE-model and PESQ is investigated and a correction formula is proposed to correctthe deviation in speech quality estimation. Another extension to the E-model to improve its accuracy in comparison withthe PESQ looks into the content of the degraded signal and classifies packet lossinto either Voiced or Unvoiced based on the received surrounding packets. The accuracyof the proposed method is evaluated by comparing the estimation of the newmethod that takes packet class into consideration with the measurement providedby PESQ as a more accurate, intrusive method for measuring the speech quality. The above two extensions for quality estimation of the E-model are combinedto offer a method for estimating the quality of VoIP applications accurately, nonintrusivelywithout the need for the time-consuming, expensive, and hard to conductsubjective tests. Finally, the applicability of the E-model or the modified E-model in measuringthe quality of services in Service Oriented Computing (SOC) is illustrated.

A complete and systematic treatment of signal processing for VoIP voice and fax This book presents a consolidated view and basic approach to signal processing for VoIP voice and fax solutions. It provides readers with complete coverage of the topic, from how things work in voice and fax modules, to signal processing aspects, implementation, and testing. Beginning with an overview of VoIP infrastructure, interfaces, and signals, the book systematically covers: Voice compression Packet loss concealment techniques DTMF detection, generation, and rejection Wideband voice modules operation VoIP Voice-Network bit rate calculations VoIP voice testing Fax over IP and modem over IP Country deviations of PSTN mapped to VoIP VoIP on different processors and architectures Generic VAD-CNG for waveform codecs Echo cancellation Caller ID features in VoIP Packetization—RTP, RTCP, and jitter buffer Clock sources for VoIP applications Fax operation on PSTN, modulations, and fax messages Fax over IP payload formats and bit rate calculations Voice packets jitter with large data packets VoIP voice quality Over 100 questions and answers on voice and more than seventy questions and answers on fax are provided at the back of the book to reinforce the topics covered throughout the text. Additionally, several clarification, interpretation, and discussion sections are included in selected chapters to aide in readers' comprehension. VoIP Voice and Fax Signal Processing is an indispensable resource for professional electrical engineers, voice and fax solution developers, product and deployment support teams, quality assurance and test engineers, and computer engineers. It also serves as a valuable textbook for graduate-level students in electrical engineering and computer engineering courses.

The quality of a telecommunication voice service is largely inftuenced by the quality of the transmission system. Nevertheless, the analysis, synthesis and prediction of quality should take into account its multidimensional aspects. Quality can be regarded as a point where the perceived characteristics and the desired or expected ones meet. A schematic is presented which classifies different entities which contribute to the quality of a service, taking into account conversational, user as weIl as service related contributions. Starting from this concept, perceptively relevant constituents of speech communication quality are identified. The perceptive factors result from ele ments of the transmission configuration. A simulation model is developed and implemented which allows the most relevant parameters of traditional trans mission configurations to be manipulated, in real time and for the conversation situation. Inputs into the simulation are instrumentally measurable quality elements commonly used in transmission planning of telephone networks. A reduced set of these quality elements forms a basis for models which aim at predicting mouth-to-ear quality as it would be perceived by a user of the sys tem. These models are an important tool for the planner of telecommunication networks, as they allow the expected quality to be estimated in advance, even before the network has been set up. Two well-known models (the SUBMOD and the E-model) are analyzed in more detail, with an emphasis on the psy choacoustic and psychophysical backgrounds.

VoIP (Voice over Internet Protocol), the next big advance in telecom, has proven difficult to implement. This resource gives service and enterprise telecom managers all the data they need on measurements, tools, and utilities to build a Voice over IP service that works as well as the telephone. * Offers specific techniques for evaluating every factor that affects quality of service * Written in an easy-to-understand "plain English" style * Explains how to translate problems of quality into measurable cause and effect

Foundations of Voice and Speech Quality Perception starts out with the fundamental question of: "How do listeners perceive voice and speech quality and how can these processes be modeled?" Any quantitative answers require measurements. This is natural for physical quantities but harder to imagine for perceptual measurands. This book approaches the problem by actually identifying major perceptual dimensions of voice and speech quality perception, defining units wherever possible and offering paradigms to position these dimensions into a structural skeleton of perceptual speech and voice quality. The emphasis is placed on voice and speech quality assessment of systems in artificial scenarios. Many scientific fields are involved. This book bridges the gap between two quite diverse fields, engineering and humanities, and establishes the new research area of Voice and Speech Quality Perception.

Voice over Internet Protocol (VoIP) is an emerging technology with the potential to assist the United States Marine Corps in solving communication challenges stemming from modern operational concepts. This thesis conducts a review of VoIP standards and develops an H.323-based testbed for the study of tactical wireless VoIP performance. Methods of collecting and presenting voice quality parameters in packet-based networks are explored. Incorporation of an Adtech SX/14 Data Channel Simulator provides user control of a SONET-simulated wireless channel. Experiments quantify the effect of channel injected error rate on received voice traffic. Plots are generated to illustrate the relationship between channel error rate, packet loss, and the listening quality mean opinion score. Experimental results are extended by incorporating E-model delay considerations. Commercial voice recognition software is successfully used to measure the impact of the channel on speech intelligibility. The experiments and analysis conducted provide a cost effective approach to non-intrusive, objective voice quality assessment.