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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Design and Implementation of the Precision Personnel Locator Digital Transmitter System

Daempfling, Hauke C 20 December 2006 (has links)
"The Precision Personnel Locator project is an ongoing research project funded by the Department of Justice, the goal of which is to provide sub-meter accuracy tracking and location of first responders inside of buildings with no pre-existing infrastructure, especially in emergency situations. The PPL system consists of wearable, battery-powered Locator devices that transmit a multi-carrier “ranging signal” waveform and Reference Units that receive this ranging signal and relay the information to a Base Station for location estimation processing and display. This thesis describes the design and implementation of a subset of the Locator devices’ functionality, including: the digital generation of the ranging signal waveform; the coordination of the transmissions of many Locator devices using time-sharing methods to prevent overlap of the signals; and finally, the gathering of environmental data such as temperature and movement of the wearer and the relaying of this data back to the Base Station. To perform these tasks, two subsystems were designed and implemented as printed circuit boards. The first of these is the Data Channel, which is a low power, general-purpose communications platform that is capable of controlling the transmissions of the Locator devices with support for up to 100 Locators transmitting every second, and it can control the power of the Locator devices by switching portions of the system off when they are not in use. It also includes sensors to measure the ambient temperature, movement of the device, and a “distress button” that a first responder can press to trigger a distress signal to be transmitted to the outside of the building. The second subsystem is the Digital Waveform Generator, which consists of a Field-Programmable Gate Array (FPGA) and Digital-to-Analog Converter (DAC) that are capable of generating waveforms of up to 200 MHz bandwidth. The new Locator hardware can operate on battery power for many days. The two subsystems were successfully tested and will serve as an important step towards the goal of developing a deployable location and tracking system."
42

IEC-61850: interoperabilidade e intercambialidade entre equipamentos de supervisão, controle e proteção através das redes de comunicação de dados / IEC-61850: interoperability and interchangeability between supervision, control and protection equipment using data communication networks

Juliano Coêlho Miranda 27 April 2009 (has links)
Os sistemas de comunicação de dados sempre foram considerados um fator crítico na operação em tempo real do sistema elétrico de potência, devido a necessidade de decisões rápidas e precisas em pontos geograficamente distribuídos, desde usinas geradoras de energia até interfaces de usuários. Com a tecnologia digital, as medições, sinalizações e comandos são encapsulados em pacotes de dados que trafegam na rede da subestação, utilizando protocolos que estabelecem os formatos, as regras, os métodos, negociando e concordando no uso de parâmetros, que assegurem o transporte de informações entre dois ou mais dispositivos do sistema de automação da subestação. Uma vez que o número de protocolos de comunicação tem se tornado um desafio para usuários e fabricantes, criando ilhas de informação, o padrão IEC-61850 busca harmonizar a diversidade de equipamentos e fabricantes, e possibilitar a integração de dados para que o máximo dos benefícios possa ser extraído. Como proposta que principia esta dissertação, ambiciona-se expor a implementação no Laboratório de Sistemas de Energia Elétrica, da Universidade de São Paulo, de uma infra-estrutura de comunicação de dados e redes de computadores, Intranet, que possibilita experimentação, medição, analise e avaliação da interoperabilidade de informações, e intercambialidade de equipamentos com supervisão, controle e proteção, essencialmente, reles digitais comerciais, aqui denominados equipamentos eletrônicos inteligentes. Com o intuito de desenvolver aplicações focadas ao estudo da automação de subestações entre os níveis de processo e bay, utilizando a infraestrututa supracitada, apresenta-se neste trabalho uma lógica para controle de um bay típico de saída de linha, dispondo de meios de comunicação de dados, e uma lógica para comutação entre fontes de alta tensão em uma subestação industrial. Estes casos oportunizaram a realização de testes quanto a troca de informações adotando o padrão IEC-61850 como protocolo de comunicação, e a rede Ethernet em substituição a fiação paralela, freqüentemente utilizada como canal de comunicação, alem da intercambialidade entre dispositivos eletrônicos inteligentes de fabricantes distintos. Houve em 100% dos casos evidenciados, correta recepção dos comandos via fiação paralela ou mensagens GOOSE. Através dos resultados obtidos, percebeu-se a estabilidade e eficiência das lógicas implementadas e uma redução nos tempos necessários para troca de informações após migração para o padrão IEC-61850. Neste ínterim, busca-se avaliar o comportamento no tempo de mensagens do tipo GOOSE, Generic Object Oriented Substation Event, em condições distintas de trafego e de configuração da topologia lógica da rede de comunicação, monitorando um possível extravio entre as mensagens geradas por um emissor e aquelas recebidas por um ou mais destinatários. Em todas as aplicações foi utilizada uma metodologia para especificar a automação das lógicas discretas mediante emprego do padrão IEC-61850, caracterizando conceitos, como, por exemplo, a especificação funcional das aplicações, o mapeamento das informações enviadas e recebidas, a definição do tipo de no lógico utilizado, a configuração do serviço de mensagens GOOSE e, a atribuição da estrutura de dados de cada no lógico aos pontos pertinentes dentro das lógicas preestabelecidas. Os resultados obtidos refletiram no ambiente laboratorial demandas reais solicitadas pelo sistema elétrico de potência. / Data communication has always been considered as a critical factor in real time operation of electric power systems. This is due to the need for fast and accurate decisions at different locations, from power generation to the user interfaces. With the digital technology, measurement, signals and commands are encrypted into data packets that travels on the substation network, using protocols that provide the format, rules, methods, dealing with parameters which ensure the traffic of information between two or more devices in the substation automation system. Since the number of communication protocols has become a challenge for users and manufacturers, creating islands of information, the IEC-61850 standard seeks for harmonization of the different equipment and manufacturers, enabling the integration of data for maximum performance. The proposal of this work is the actual implementation, at the Energy Systems Laboratory from the University of Sao Paulo, of an infrastructure of data communication network, which allows experimentation, measurement, analysis and assessment of information, interoperability and interchangeability of supervision, control and protection equipment, especially Intelligent Electronic Devices (IEDs). In order to develop applications focused on the study of automation of substations between the process and bay levels, using the infrastructure mentioned above, a logic to bay control using data communication, as well as a logic for high voltage source switching are presented. These situations test information exchange using the IEC-61850 standard as a communication protocol, and the Ethernet network replacing parallel wiring. It also tests the interchangeability amongst IEDs from different manufacturers. There were in 100% of the cases tested, correct reception of commands using parallel wiring or GOOSE messages. From the results, the stability and efficiency of the implemented logic can be observed as well as a reduction in time required to exchange information in the system. Moreover, a behavior evaluation in time of GOOSE messages was implemented for different traffic and topology conditions, monitoring possible loss of messages. In all applications a methodology to specify the automation of discrete logic using the standard IEC-61850 was implemented, featuring concepts, such as the functional specification of the applications, data mapping, the definition of the type of logic node used, the configuration of GOOSE, as well as the allocation of data structure for each logical node. The results reflects in the laboratory environment the demands requested by an actual electric power system.
43

Smart Case for Remote Radio Kit

Östlund, Emil January 2019 (has links)
The thesis aims to develop a prototype for a Smart Case for Remote Radio Kits at the department of Demo & Event at Ericsson in Kista.The smart case consists of a mechanical structure (the case itself with ) and an electronic system that includes a temperature sensor, a LCD display showing the temperature, a GPS (global positioning system) module for positioning the case, a GSM (Global System for Mobile Communications) module and a microcontroller Arduino UNO. The Case is modelled in 3D with the help of CAD software and then printed with a 3D printer. A down-scaled prototype is built with the help of the 3D printer and the 2D drawing will be used when the full scaled model is produced. The Arduino UNO handles temperature sensor and GPS measurements, LCD display, and the transmission of measurement data using GSM module via text message (SMS) to a cell phone or to a server over the Internet. The projected ended up with all the drawings and models finished for the Case as well as the implementation of down-scaled prototypes. The electrical system was tested and finished individually. But the complete system cannot be assembled inside the Case due to the time limitation. This means that the project can be further extended, where a full scale model can be developed and the electrical control system can be assembled together and mounted inside the Case.
44

Prototyp av en VoIP/PSTN-gateway / Prototype of a VoIP/PSTN gateway

Broström, Anders, Kihlstadius, Niclas January 2007 (has links)
<p>Under de senaste åren har Internettelefonin varit på frammarsch, och i takt med att tekniken mognat har fler och fler börjat se den som ett alternativ till att ringa via telefonnätet. Förutom att det är billigare att ringa över det förstnämnda, så erbjuder Internettelefonin också en rad revolutionerande tjänster. Det är dock troligt att telefonnätet kommer att få tjänstgöra i många år till, och det erbjuder fortfarande överlägset bäst stabilitet och har stor acceptans. Om de två telefoninätverken ska existera sida vid sida, med varsina användarbaser är det lämpligt om de kan fås att samverka, så att användare av det ena kan ringa användare av det andra, och vice versa. Detta kan göras med en VoIP/PSTN-gateway, som översätter kontrollinformation och rösttrafik mellan de två nätverken.</p><p>Uppsatsen handlar om det arbete vi har utfört år TietoEnator i Karlstad. Uppgiften bestod i att utveckla en prototyp av en VoIP/PSTN-gateway. Från början var det avsett att systemet skulle klara uppringning från endera en ”vanlig” telefon, eller en så kallad IP-telefon. Därtill skulle rösttrafiken överföras genom ändamålsenlig hårdvara. För att utföra arbetet behövde vi först studera relevanta kommunikationsprotokoll både för telefonnätet och för Internet, för att se hur dessa kunde fås att samverka. Vi behövde också lära oss tillgängliga system, bibliotek och verktyg för att förstå hur vi skulle skapa vårt eget system i den efterkommande implementeringsfasen. På grund av en lång inläsningsperiod och inledande tekniska problem, samt att nödvändig hårdvara för översättning av rösttrafiken inte anlände i tid begränsades arbetet till att innefatta samtal initierade från den vanliga telefonen till ip-telefonen, utan röstöverföring. Likväl har ett resultatgivande arbete utförts, och det beskrivs i detalj i rapporten.</p> / <p>During the past few years Internet telephony has advanced rapidly, and as the technology has evolved, more and more have come to consider it an alternative to making phone calls through the telephone network. Besides being cheaper, Internet telephony also provides several revolutionary services. It is likely though that the telephone network will remain in use for several years to come, and it still offers by far the best stability and is accepted by most people. If the two networks are to coexist, with their respective users, it would be useful if they could be made to interact, so that users of one network can call users of the other, and vice versa. This can be done with a VoIP/PSTN gateway, which translates control information and voice traffic between the two networks.</p><p>Our dissertation is about the work we have performed for TietoEnator in Karlstad. The assignment was to develop a prototype of a VoIP/PSTN gateway. Initially the system was meant to support phone calls initiated either from an “ordinary” phone or from an IP telephone. Also the voice traffic was supposed to be translated with the use of appropriate hardware. To manage this we first needed to study all the relevant protocols for communication used in the telephone network and on the Internet, to get an idea of how these could be made to interact. We also had to learn existing systems, libraries and tools in order to see how we could create our own system. Due to a long learning period and technical problems in the beginning, and because the necessary hardware equipment for translation of voice traffic did not arrive in time, the assignment was limited to include only calls initiated from the ordinary phone to the IP telephone, without voice transmission. Never the less, the efforts have produced results, and our work is explained in detail in this dissertation.</p>
45

Interference Management For Vector Gaussian Multiple Access Channels

Padakandla, Arun 03 1900 (has links)
In this thesis, we consider a vector Gaussian multiple access channel (MAC) with users demanding reliable communication at specific (Shannon-theoretic) rates. The objective is to assign vectors and powers to these users such that their rate requirements are met and the sum of powers received is minimum. We identify this power minimization problem as an instance of a separable convex optimization problem with linear ascending constraints. Under an ordering condition on the slopes of the functions at the origin, an algorithm that determines the optimum point in a finite number of steps is described. This provides a complete characterization of the minimum sum power for the vector Gaussian multiple access channel. Furthermore, we prove a strong duality between the above sum power minimization problem and the problem of sum rate maximization under power constraints. We then propose finite step algorithms to explicitly identify an assignment of vectors and powers that solve the above power minimization and sum rate maximization problems. The distinguishing feature of the proposed algorithms is the size of the output vector sets. In particular, we prove an upper bound on the size of the vector sets that is independent of the number of users. Finally, we restrict vectors to an orthonormal set. The goal is to identify an assignment of vectors (from an orthonormal set) to users such that the user rate requirements is met with minimum sum power. This is a combinatorial optimization problem. We study the complexity of the decision version of this problem. Our results indicate that when the dimensionality of the vector set is part of the input, the decision version is NP-complete.
46

Μοντελοποίηση και υλοποίηση συστήματος μηνυματοδοσίας για υπηρεσίες τηλεματικής στο χώρο της Υγείας

Κολοβού, Λαμπρινή 01 February 2008 (has links)
Στην παρούσα διατριβή αντιμετωπίζονται προβλήματα που αφορούν στην διαλειτουργικότητα, στο επίπεδο της ‘επικοινωνίας δεδομένων’, κατά την επικοινωνία διαφορετικών ιατρικών πληροφοριακών συστημάτων – ΙΠΣ, τα οποία ανήκουν σε οργανισμούς παροχής ιατρικής φροντίδας, με τον σχεδιασμό και την υλοποίηση ενός Μοντέλου Αναφοράς Ανάπτυξης – ΜΑΑ. Το ΜΑΑ προτείνει ένα πλαίσιο εργασίας για την ανάπτυξη Συστημάτων Διαχείρισης Μηνυμάτων – ΣΔΜ, ικανών να υποστηρίζουν την επικοινωνία διαφορετικών ΙΠΣ στο χώρο του Νοσοκομείου και περιγράφει: (α) την κοινή συντακτική δομή της πληροφορίας που ανταλλάσσεται, (β) τις κοινές κατατομές επικοινωνίας των οντοτήτων των ΙΠΣ, (γ) τη γενική αρχιτεκτονική του ενδιάμεσου συστήματος και (δ) ένα σύνολο διεργασιών και υπηρεσιών που υλοποιούν τη διαδικασία της μηνυματοδοσίας, αλλά και την επίβλεψη, τον έλεγχο και τη συντήρηση αυτής. Επιπλέον, η παρούσα διατριβή εστιάζεται και στην υλοποίηση ενός ΣΔΜ, το οποίο εξυπηρετεί την επικοινωνία τριών βασικών ΙΠΣ του νοσοκομείου και είναι πλήρωως συμμορφωμένο με τις προτεινόμενες προδιαγραφές. Η αξιολόγηση του ΜΑΑ πραγματοποιήθηκε με την εφαρμογή τριών διαφορετικών μεθόδων: την πρακτική εφαρμογή του ΜΑΑ, την αξιολόγηση των ‘κριτηρίων χρήσης’ του και την προσέγγιση των ‘διαστάσεων ποιότητας’. / The present dissertation addresses interoperability issues, ion the ‘data communication level’, that concern the communication between heterogeneous Medical Information Systems (MISs) of healthcare organizations, through the design and implementation of a Reference Implementation Model (RImM). The RImM introduces a framework for the implementation of Message Handling Systems (MHSs) that supports the interoperable communication of different MISs inbound and outbound healthcare organizations and concerns: (a) the common syntactic structure of the transferred information, (b) the communication profiles of the MISs’ functional entities, (c) the general architecture of the intermediate system and (d) the set of interactions and service elements that implement the messaging service and the surveillance, control and maintenance of it. Furthermore, the dissertation focuses on the implementation of such a MHS that supports the communication of three basic MISs. The efficiency estimation of the proposed RImM were assessed applying three different methods: (a) the practical application of RImM and pilot operation of the implemented MHS, (b) the evaluation of ‘criteria of use’ and (c) the evaluation of ‘quality dimensions’ that concern reference modeling.
47

Measurements and analysis of UDP transmissions over wireless networks

Berglund, Joel January 2018 (has links)
The growth and expansion of modern society rely heavily upon well-functioning data communication over the internet. This phenomenon is seen at the company Net Insight where the need for transferring a large amount of data in the form of media over the internet in an effective manner is a high priority. At the moment most internet traffic in the modern world is done by the use of the internet protocol TCP (Transmission Control Protocol) instead of the simpler protocol UDP (User Datagram Protocol). Although TCP works in an excellent manner for most kinds of data communication it seems that this might not always be the case, so the use of UDP might be the better option in some occurrences. It is therefore of high interest at Net Insight to see how different types of wireless networks behave under different network circumstances when data is sent in different ways through the use of UDP. Thereby this report focuses on the measurement and analysis of how different wireless networks, specifically 4G, 5.0 GHz and 2.4 GHz WLAN networks, behaves when exposed to varied network environments where data is transmitted by the use of UDP in different ways. To perform a network-analysis data is collected, processed, and then analyzed. This network-analysis resulted in many conclusions regarding network behavior and performance for the different wireless networks.
48

Proposta e modelagem de comunicação segura para redes veiculares (VANETS)

Barbieri, Wellington Reina [UNESP] 30 November 2012 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:29:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-11-30Bitstream added on 2014-06-13T20:59:56Z : No. of bitstreams: 1 barbieri_wr_me_sjrp.pdf: 2320293 bytes, checksum: 788cbe9d3961bfd57dff3fb3c4ddd93c (MD5) / Os avanços constantes da tecnologia, a facilidade da troca de informação em todas as áreas conhecidas e equipamentos cada vez mais sofisticados apresentam um cenário onde se torna imprescindível uma infraestrutura que proporcione comunicação entre os veículos que circulam nas cidades e rodovias, para haver uma maior segurança no tráfego. Esta ferramenta conhecida como VANET (Vehicular Ad Hoc NETwork) é uma subclasse da redes Ad Hoc que tem como objetivo a comunicação entre veículos e/ou entre veículos e uma infraestrutura de acostamento, e tem a finalidade de proporcionar segurança e autonomia nas vias rodoviárias. Mas esta troca de informação ainda é frágil e cada vez mais fácil de ser interceptada. Com o intuito de minimizar as invasões e interceptações, foi proposta a utilização do protocolo TESLA (Timed Efficient Stream Loss-Tolerant Authentication) que é um protocolo de segurança utilizado na troca de informações nas comunicações e baseiase na perda de tempo de sincronização entre o emissor e o receptor. O objetivo deste trabalho é modelar em UML e Fluxograma a alteração na comunicação na rede VANET, sendo possível escolher qual protocolo será utilizado e a segurança no protocolo TESLA, que tornará possível a escolha de qual criptografia utilizar, e para esta modelagem está prevista a utilização da técnica da Criptografia das Curvas Elípticas – ECC / The constant advances in technology, the ease of information exchange in all areas, and increasingly sophisticated equipment present a scenario where it becomes essential to have an infrastructure that provides communication between vehicles traveling in cities and highways to be safer in traffic. This tool is known as VANET (Vehicular Ad hoc NETwork) and is a subclass of ad hoc networks that aims communication between vehicles and/or between vehicles and roadside infrastructure, in order to provide security and autonomy roads. But, this exchange of information is still fragile and increasingly easy to be intercepted. In order to minimize intrusions and hijacks, it was proposed to use the TESLA protocol (Timed Efficient Stream LossTolerant Authentication), which is a security protocol used in the communication exchange and based on the loss of synchronization time between transmitter and receiver. The objective of this work is to model in UML and Flowchart change in the VANET network communication, and can choose which protocol will be used and safety at TESLA protocol, which make it possible to choose which encryption to use, and this model is expected to use the technique of Elliptic Curve Cryptography ECC
49

Proposta e modelagem de comunicação segura para redes veiculares (VANETS) /

Barbieri, Wellington Reina. January 2012 (has links)
Orientador: Marcos Antônio Cavenaghi / Banca: Aparecido Nilceu Marana / Banca: Sarita Mazzini Bruschi / Resumo: Os avanços constantes da tecnologia, a facilidade da troca de informação em todas as áreas conhecidas e equipamentos cada vez mais sofisticados apresentam um cenário onde se torna imprescindível uma infraestrutura que proporcione comunicação entre os veículos que circulam nas cidades e rodovias, para haver uma maior segurança no tráfego. Esta ferramenta conhecida como VANET (Vehicular Ad Hoc NETwork) é uma subclasse da redes Ad Hoc que tem como objetivo a comunicação entre veículos e/ou entre veículos e uma infraestrutura de acostamento, e tem a finalidade de proporcionar segurança e autonomia nas vias rodoviárias. Mas esta troca de informação ainda é frágil e cada vez mais fácil de ser interceptada. Com o intuito de minimizar as invasões e interceptações, foi proposta a utilização do protocolo TESLA (Timed Efficient Stream Loss-Tolerant Authentication) que é um protocolo de segurança utilizado na troca de informações nas comunicações e baseia"se na perda de tempo de sincronização entre o emissor e o receptor. O objetivo deste trabalho é modelar em UML e Fluxograma a alteração na comunicação na rede VANET, sendo possível escolher qual protocolo será utilizado e a segurança no protocolo TESLA, que tornará possível a escolha de qual criptografia utilizar, e para esta modelagem está prevista a utilização da técnica da Criptografia das Curvas Elípticas - ECC / Abstract: The constant advances in technology, the ease of information exchange in all areas, and increasingly sophisticated equipment present a scenario where it becomes essential to have an infrastructure that provides communication between vehicles traveling in cities and highways to be safer in traffic. This tool is known as VANET (Vehicular Ad hoc NETwork) and is a subclass of ad hoc networks that aims communication between vehicles and/or between vehicles and roadside infrastructure, in order to provide security and autonomy roads. But, this exchange of information is still fragile and increasingly easy to be intercepted. In order to minimize intrusions and hijacks, it was proposed to use the TESLA protocol (Timed Efficient Stream Loss"Tolerant Authentication), which is a security protocol used in the communication exchange and based on the loss of synchronization time between transmitter and receiver. The objective of this work is to model in UML and Flowchart change in the VANET network communication, and can choose which protocol will be used and safety at TESLA protocol, which make it possible to choose which encryption to use, and this model is expected to use the technique of Elliptic Curve Cryptography " ECC / Mestre
50

Prototyp av en VoIP/PSTN-gateway / Prototype of a VoIP/PSTN gateway

Broström, Anders, Kihlstadius, Niclas January 2007 (has links)
Under de senaste åren har Internettelefonin varit på frammarsch, och i takt med att tekniken mognat har fler och fler börjat se den som ett alternativ till att ringa via telefonnätet. Förutom att det är billigare att ringa över det förstnämnda, så erbjuder Internettelefonin också en rad revolutionerande tjänster. Det är dock troligt att telefonnätet kommer att få tjänstgöra i många år till, och det erbjuder fortfarande överlägset bäst stabilitet och har stor acceptans. Om de två telefoninätverken ska existera sida vid sida, med varsina användarbaser är det lämpligt om de kan fås att samverka, så att användare av det ena kan ringa användare av det andra, och vice versa. Detta kan göras med en VoIP/PSTN-gateway, som översätter kontrollinformation och rösttrafik mellan de två nätverken. Uppsatsen handlar om det arbete vi har utfört år TietoEnator i Karlstad. Uppgiften bestod i att utveckla en prototyp av en VoIP/PSTN-gateway. Från början var det avsett att systemet skulle klara uppringning från endera en ”vanlig” telefon, eller en så kallad IP-telefon. Därtill skulle rösttrafiken överföras genom ändamålsenlig hårdvara. För att utföra arbetet behövde vi först studera relevanta kommunikationsprotokoll både för telefonnätet och för Internet, för att se hur dessa kunde fås att samverka. Vi behövde också lära oss tillgängliga system, bibliotek och verktyg för att förstå hur vi skulle skapa vårt eget system i den efterkommande implementeringsfasen. På grund av en lång inläsningsperiod och inledande tekniska problem, samt att nödvändig hårdvara för översättning av rösttrafiken inte anlände i tid begränsades arbetet till att innefatta samtal initierade från den vanliga telefonen till ip-telefonen, utan röstöverföring. Likväl har ett resultatgivande arbete utförts, och det beskrivs i detalj i rapporten. / During the past few years Internet telephony has advanced rapidly, and as the technology has evolved, more and more have come to consider it an alternative to making phone calls through the telephone network. Besides being cheaper, Internet telephony also provides several revolutionary services. It is likely though that the telephone network will remain in use for several years to come, and it still offers by far the best stability and is accepted by most people. If the two networks are to coexist, with their respective users, it would be useful if they could be made to interact, so that users of one network can call users of the other, and vice versa. This can be done with a VoIP/PSTN gateway, which translates control information and voice traffic between the two networks. Our dissertation is about the work we have performed for TietoEnator in Karlstad. The assignment was to develop a prototype of a VoIP/PSTN gateway. Initially the system was meant to support phone calls initiated either from an “ordinary” phone or from an IP telephone. Also the voice traffic was supposed to be translated with the use of appropriate hardware. To manage this we first needed to study all the relevant protocols for communication used in the telephone network and on the Internet, to get an idea of how these could be made to interact. We also had to learn existing systems, libraries and tools in order to see how we could create our own system. Due to a long learning period and technical problems in the beginning, and because the necessary hardware equipment for translation of voice traffic did not arrive in time, the assignment was limited to include only calls initiated from the ordinary phone to the IP telephone, without voice transmission. Never the less, the efforts have produced results, and our work is explained in detail in this dissertation.

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