A Model for Emergency Service of VoIP through Certification and Labeling

Voice over Internet Protocol (VoIP) will transform many aspects of traditional telephony service, including the technology, the business models, and the regulatory constructs that govern such service. Perhaps not unexpectedly, this transformation is generating a host of technical, business, social, and policy problems. In attempting to respond to these problems, the Federal Communications Commission (FCC) could mandate obligations or specific solutions to VoIP policy issues; however, it is instead looking first to industry initiatives focused on the key functionality that users have come to expect of telecommunications services. High among this list of desired functionality is user access to emergency services for purposes of summoning fire, medical, and law enforcement agencies. Such services were traditionally required to be implemented (and subsequently were implemented) through state and federal regulations. An emergency service capability is a critical social concern, making it particularly important for the industry to propose viable solutions for promoting VoIP emergency services before regulators are compelled to mandate a solution. Reproducing emergency services in the VoIP space has proven to be a considerable task, mainly due to the wide and diverse variety of VoIP implementations and implementers. While technical and business communities have, in fact, made considerable progress in this area, significant uncertainty and deployment problems still exist. The question we ask is this: Can an industry-based certification and labeling process credibly address social and policy expectations regarding emergency services and VoIP, thus avoiding the need for government regulation at this critical time? We hypothesize that the answer is “yes.” In answering this question, we developed a model for VoIP emergency service compliance through industry certification and device labeling. This model is intended to support a wide range of emergency service implementations while providing users with sufficient verification that the service will operate as anticipated. To this end, we first examine possible technical implementations for VoIP emergency services. Next, we summarize the theory of certification as self-regulation and examine several relevant examples. Finally, we synthesize a specific model for certification of VoIP emergency services. We believe that the model we describe provides both short-term and long-term opportunities. In the short term, an industry-driven effort to solve the current problem of VoIP emergency services, if properly structured and overseen as we suggest, should be both effective and efficient. In the long term, such a process can serve as a self-regulatory model that can be applied to social policy goals in the telecommunications industry, making it an important tool to have as the industry becomes increasingly diverse and heterogeneous

Radio Communications

In the last decades the restless evolution of information and communication technologies (ICT) brought to a deep transformation of our habits. The growth of the Internet and the advances in hardware and software implementations modified our way to communicate and to share information. In this book, an overview of the major issues faced today by researchers in the field of radio communications is given through 35 high quality chapters written by specialists working in universities and research centers all over the world. Various aspects will be deeply discussed: channel modeling, beamforming, multiple antennas, cooperative networks, opportunistic scheduling, advanced admission control, handover management, systems performance assessment, routing issues in mobility conditions, localization, web security. Advanced techniques for the radio resource management will be discussed both in single and multiple radio technologies; either in infrastructure, mesh or ad hoc networks

Characterisation of noisy speech channels in 2G and 3G mobile networks

As the wireless cellular market reaches competitive levels never seen before, network operators need to focus on maintaining Quality of Service (QoS) a main priority if they wish to attract new subscribers while keeping existing customers satisfied. Speech Quality as perceived by the end user is one major example of a characteristic in constant need of maintenance and improvement. It is in this topic that this Master Thesis project fits in. Making use of an intrusive method of speech quality evaluation, as a means to further study and characterize the performance of speech codecs in second-generation (2G) and third-generation (3G) technologies. Trying to find further correlation between codecs with similar bit rates, along with the exploration of certain transmission parameters which may aid in the assessment of speech quality. Due to some limitations concerning the audio analyzer equipment that was to be employed, a different system for recording the test samples was sought out. Although the new designed system is not standard, after extensive testing and optimization of the system's parameters, final results were found reliable and satisfactory. Tests include a set of high and low bit rate codecs for both 2G and 3G, where values were compared and analysed, leading to the outcome that 3G speech codecs perform better, under the approximately same conditions, when compared with 2G. Reinforcing the idea that 3G is, with no doubt, the best choice if the costumer looks for the best possible listening speech quality. Regarding the transmission parameters chosen for the experiment, the Receiver Quality (RxQual) and Received Energy per Chip to the Power Density Ratio (Ec/N0), these were subject to speech quality correlation tests. Final results of RxQual were compared to those of prior studies from different researchers and, are considered to be of important relevance. Leading to the confirmation of RxQual as a reliable indicator of speech quality. As for Ec/N0, it is not possible to state it as a speech quality indicator however, it shows clear thresholds for which the MOS values decrease significantly. The studied transmission parameters show that they can be used not only for network management purposes but, at the same time, give an expected idea to the communications engineer (or technician) of the end-to-end speech quality consequences. With the conclusion of the work new ideas for future studies come to mind. Considering that the fourth-generation (4G) cellular technologies are now beginning to take an important place in the global market, as the first all-IP network structure, it seems of great relevance that 4G speech quality should be subject of evaluation. Comparing it to 3G, not only in narrowband but also adding wideband scenarios with the most recent standard objective method of speech quality assessment, POLQA. Also, new data found on Ec/N0 tests, justifies further research studies with the intention of validating the assumptions made in this work.Com o mercado das redes móveis a atingir níveis de competitividade nunca antes vistos, existe a crescente necessidade por parte dos operadores de rede em focar-se na Qualidade de Serviço (QoS) como principal prioridade, no sentido de atrair novos clientes ao mesmo tempo que asseguram a satisfação dos seus actuais assinantes. A percepção da Qualidade de Voz, por parte do utilizador, é apenas um exemplo de uma característica de QoS em constante necessidade de manutenção e melhoramento. Sendo nesta temática em que se insere a Tese de Mestrado. Aplicando um método intrusivo de avaliação de qualidade de voz, como meio para um estudo mais aprofundado e, ao mesmo tempo, caracterizando o desempenho dos codecs de voz para as tecnologias de segunda-geração (2G) e terceira-geração (3G). Investigando nova informação que possa ser retirada da correlação entre codecs com bit rates semelhantes, juntamente com a exploração de determinados 'parâmetros de transmissão os quais podem auxiliar na avaliação da qualidade de voz. Devido a algumas limitações ligadas ao analisador de áudio (requisito neste tipo de aplicações), existiu a necessidade de procurar um sistema distinto para gravação das amostras de teste. Embora o sistema escolhido não seja padronizado para este tipo de ensaios, após vários testes e consequente optimização dos parâmetros do sistema, os resultados finais consideram-se credíveis e satisfatórios. Os testes efectuados incluem um conjunto de codecs de elevado e baixo bit rate, onde a comparação e análise dos resultados levam a concluir que codecs de voz 3G têm melhor desempenho, sob aproximadamente as mesmas condições, comparativamente com os 2G. Reforçando a ideia generalizada que 3G é, sem dúvida, a melhor escolha se o utilizador procura uma solução superior a nível de qualidade de voz. No que diz respeito aos parâmetros de transmissão escolhidos para a experiência, RxQual (Qualidade do sinal Recebido pela estacão móvel) e Ec/N0 (razão entre Energia por chip e a Densidade Espectral de Potência), estes foram sujeitos a testes de correlação com a qualidade de voz. Os resultados de RxQual foram sujeitos a comparação com estudos prévios de outros investigadores, confirmando este parâmetro como um indicador de qualidade de voz bastante fiável. Quanto a Ec/N0, não é possível declará-lo como um indicador de qualidade de voz, no entanto, este demonstra limites claros para os quais os valores de Mean Opinion Score (MOS) decrescem significativamente. Os parâmetros de transmissão estudados demonstram não só que podem ser utilizados com objectivos de gestão de rede mas como também podem fornecer, ao engenheiro (ou técnico), informação relativa ao impacto que poderá existir na qualidade de voz. Com a finalização deste trabalho é possível constatar que novos estudos devem ser efectuados. Considerando que a tecnologia de quarta-geração (4G) começa agora a dar os seus primeiros passos no mercado das redes móveis, como a primeira com arquitectura de rede totalmente orientada para IP, parece de grande importância que esta tecnologia seja sujeita a avaliação. Comparando-a com 3G, não só para banda-estreita (300 a 3400 Hz) como também para cenários de banda-larga (50 a 7000Hz), aplicando o mais recente método normalizado de avaliação de qualidade de voz, o POLQA. Por fim, também se verifica como pertinente uma continuação do estudo relativo a Ec/N0 a fim de validar as ilações retiradas neste trabalho

The space physics environment data analysis system (SPEDAS)

With the advent of the Heliophysics/Geospace System Observatory (H/GSO), a complement of multi-spacecraft missions and ground-based observatories to study the space environment, data retrieval, analysis, and visualization of space physics data can be daunting. The Space Physics Environment Data Analysis System (SPEDAS), a grass-roots software development platform (www.spedas.org), is now officially supported by NASA Heliophysics as part of its data environment infrastructure. It serves more than a dozen space missions and ground observatories and can integrate the full complement of past and upcoming space physics missions with minimal resources, following clear, simple, and well-proven guidelines. Free, modular and configurable to the needs of individual missions, it works in both command-line (ideal for experienced users) and Graphical User Interface (GUI) mode (reducing the learning curve for first-time users). Both options have “crib-sheets,” user-command sequences in ASCII format that can facilitate record-and-repeat actions, especially for complex operations and plotting. Crib-sheets enhance scientific interactions, as users can move rapidly and accurately from exchanges of technical information on data processing to efficient discussions regarding data interpretation and science. SPEDAS can readily query and ingest all International Solar Terrestrial Physics (ISTP)-compatible products from the Space Physics Data Facility (SPDF), enabling access to a vast collection of historic and current mission data. The planned incorporation of Heliophysics Application Programmer’s Interface (HAPI) standards will facilitate data ingestion from distributed datasets that adhere to these standards. Although SPEDAS is currently Interactive Data Language (IDL)-based (and interfaces to Java-based tools such as Autoplot), efforts are under-way to expand it further to work with python (first as an interface tool and potentially even receiving an under-the-hood replacement). We review the SPEDAS development history, goals, and current implementation. We explain its “modes of use” with examples geared for users and outline its technical implementation and requirements with software developers in mind. We also describe SPEDAS personnel and software management, interfaces with other organizations, resources and support structure available to the community, and future development plans.Published versio

Developing a distributed electronic health-record store for India

The DIGHT project is addressing the problem of building a scalable and highly available information store for the Electronic Health Records (EHRs) of the over one billion citizens of India