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In the traditional mobile communication networks, the bandwidth of wireless links is too small and the bandwidth difference between wireless links and wireline links is too large. This leads to limiting the application of mobile communication networks to transmit multimedia data and other high-bit rate services, and the problem of lacking bandwidth often occurs to wireless links. But the new generation mobile communication networks, called the third generation mobile communication systems (3G systems), will change this condition. Because the 3G systems will quickly enhance the transmission rate of the wireless links (up to 2Mbps) and provide better quality of transmission, the transmission of multimedia data and other high-bit rate services in the mobile communication networks can be achieved. The 3G systems can support many new services that are never supported before, and these new services always need support the point-to-multipoint transmission. In this thesis, we will discuss the problems of supporting these new services, and then we propose new multimedia multicasting architecture to overcome these problems.

Amplitude and Phase Shift Keying (APSK) format is one of the most attractive advanced modulation formats because of its good spectral efficiency. As the information bandwidth of the current optical fiber communication system is limited by the optical amplifier bandwidth, it is important to utilize the limited bandwidth effectively. This master thesis focuses on to study the transmission performance of the APSK format both theoretically and experimentally. At first, a theoretical study was conducted using a numerical simulation. As the Extinction Ratio (ER) of the Amplitude Shift Keying (ASK) signal affects the performances of both the ASK and the Phase Shift Keying (PSK) signals, the effect of the ER upon the transmission performance of the APSK format was studied. A clear trade-off between the performance of the ASK signal and the PSK signal due to the change of the ER was observed. Then, in order to improve the performance of the APSK format, a method to improve the transmission performance was proposed. This method was named as ¡§zero-nulling method¡¨, and it solved the trade-off issue caused by the ER. The effectiveness of this method was confirmed through the numerical simulation. Next, an experimental study was conducted. An experimental setup including 330km optical fiber transmission line was prepared, and it was used to confirm the results of the theoretical simulation. The performance trade-off between the ASK and the PSK signals due to the ER was confirmed experimentally. Finally, another experimental study was conducted. An experimental setup of 500km transmission line was used for this study. By adopting the recirculating loop experimental setup, the transmission length could be extended to a few thousand kilometers. The applicability of the ¡§zero-nulling method¡¨ was confirmed using this experimental setup.

Connected Me is a Human Body Communication (HBC) system, which is used fortransferring data through human body. The working principle is based on theorycalled Body Coupled Communication (BCC), which uses electrostatic couplingfor transferring data between device and human body. Capacitance between bodyand electrode acts as an electrical interface between devices. BCC has become aprominent research area in the field of Personal Area Network (PAN), introducedby Zimmerman in 1995. Until now there have been significant amount of paperspublished on human body models and Analog Front End (AFE), but only fewreports are available in digital baseband processing. The proposed Human Body Communication (HBC) system consists ofdigital baseband and AFE. Digital baseband is used for transferring data packets.AFE is designed for reconstructing signal shape after signal degradation causedby the human body. This thesis implements high speed serial digital communicationsystem for a human body channel. Available modulation schemes andcharacteristics of the Physical layer (PHY) with respect to human body channelare analyzed before implementing the system. The outcome of this thesis is aFPGA demonstrator that shows the possibility of communication through thehuman body. / Connected Me

Migrating from a wired to a wireless implementation for communication system used in industrial applications is a logical move to avoid the many shortcomings associated with wires. When operated under harsh environments, those wires can break and could cause not only damage to the system but also endanger human lives. However, it is not well documented how well a wireless protocol can work under such harsh industrial environments. This thesis attempts to answer this research question in the point of view of gauging the performance of a wireless protocol under the influence of electromagnetic noise. More specifically, the type of noise signal that is the focus of this investigation is the random, pulsed type (e.g., discharges caused by sparking) that creates a hyperbolic broadband disturbance in the frequency domain. Consequently, a fractal noise model is used to study noise of this nature. The steps toward achieving this goal include: requirements gathering, wireless technology selection; noise modelling and synthesis; real noise capture and analysis to validate the chosen noise model; high-frequency fractal noise emulation in hardware; the use of a novel noise injection method for empirical work; and the conducting of a controlled synthetic noise-to-wireless node performance evaluation to obtain performance measure in the form of packet error rate (PER). Performance data in terms of PER versus signal-to-noise ratio (SNR) for various nodes separation have been collected. There were three significant findings: the obtained performance curves follow the standard 'S' trend; for a specific desired reliability (denoted by a certain PER), the SNR at the transmitter needs to be boosted as the correlation of the noise being present increases; and the maximum distance between nodes separation for a certain reliability to be achieved depends exponentially with the transmitter‟s SNR. The relationship in the third finding assists in placement of wireless nodes, which in turn can determine the minimum amount of wireless nodes required for an industrial system to reach the desired system reliability, thus boasting network cost saving.

In todays heterogeneous network environment, there is a growing demand for distrusted parties to jointly execute distributed algorithms on private data whose secrecy needed to be safeguarded. Platforms that support such computation on image processing purposes are called secure image processing protocols. In this thesis, we propose a new security model, called quasi information theoretic (QIT) security. Under the proposed model efficient protocols on two basic image processing algorithms linear filtering and thresholding are developed. For both problems we consider two situations: 1) only two parties are involved where one holds the data and the other possesses the processing algorithm; 2) an additional non-colluding third party exists. Experiments show that our proposed protocols improved the computational time significantly compared with the classical cryptographical couterparts as well as providing reasonable amount of security as proved in the thesis

Migrating from a wired to a wireless implementation for communication system used in industrial applications is a logical move to avoid the many shortcomings associated with wires. When operated under harsh environments, those wires can break and could cause not only damage to the system but also endanger human lives. However, it is not well documented how well a wireless protocol can work under such harsh industrial environments. This thesis attempts to answer this research question in the point of view of gauging the performance of a wireless protocol under the influence of electromagnetic noise. More specifically, the type of noise signal that is the focus of this investigation is the random, pulsed type (e.g., discharges caused by sparking) that creates a hyperbolic broadband disturbance in the frequency domain. Consequently, a fractal noise model is used to study noise of this nature. The steps toward achieving this goal include: requirements gathering, wireless technology selection; noise modelling and synthesis; real noise capture and analysis to validate the chosen noise model; high-frequency fractal noise emulation in hardware; the use of a novel noise injection method for empirical work; and the conducting of a controlled synthetic noise-to-wireless node performance evaluation to obtain performance measure in the form of packet error rate (PER). Performance data in terms of PER versus signal-to-noise ratio (SNR) for various nodes separation have been collected. There were three significant findings: the obtained performance curves follow the standard 'S' trend; for a specific desired reliability (denoted by a certain PER), the SNR at the transmitter needs to be boosted as the correlation of the noise being present increases; and the maximum distance between nodes separation for a certain reliability to be achieved depends exponentially with the transmitter‟s SNR. The relationship in the third finding assists in placement of wireless nodes, which in turn can determine the minimum amount of wireless nodes required for an industrial system to reach the desired system reliability, thus boasting network cost saving.

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Orientador: Jozué Vieira Filho / Banca: Suely Cunha Amaro Mantovani / Banca: José Raimundo de Oliveira / Resumo: A aquisição de dados tem evoluído de forma significativa nos últimos anos e passa a ser indispensável em várias aplicações nas áreas de engenharia, agricultura, medicina, aeronáutica, etc. O estado da arte nessa área envolve o uso de sistemas de comunicação sem fio e da internet. Neste trabalho é apresentado um sistema moderno de aquisição de dados, que é baseado em uma comunicação sem fio via rede GSM (Global Mobile for System), com conexão via Internet através de um sistema de telefonia celular GPRS (General Packet Radio Service), monitoramento de dados via página Web (World Web Browser) e interface de aplicação com base em um microcontrolador. O sistema é bastante flexível e foi testado em operações reais no monitoramento de temperatura ambiente. Os resultados obtidos são altamente satisfatórios e mostra que o sistema pode servir de base para aplicações em diferentes áreas onde a telemetria seja indispensável. / Abstract: Data acquisition has significantly been developed in the last years and became indispensable in many application area of engineering such as agriculture, medicine, aeronautic, etc. The state of art in this area is basead on wireless communication system and Internet. In this work it is presented a modern data acquisition based on wireless communication through the Internet, which includes a Celular Mobile GPRS (General Packet Radio Service) in a GSM (Global Mobile System) network, and remote data monitoring via WEB (World Web Browser) that can be used in a Telemetry Network construction. The system was tested in real conditions as a temperature monitoring system based on a microcontroller and it has presented good results. The high flexibility model proposed allows to use it in many distinct applications that require remote data acquisition. / Mestre

Made available in DSpace on 2014-06-11T19:22:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-04-13Bitstream added on 2014-06-13T20:07:40Z : No. of bitstreams: 1 tateoki_gt_me_ilha.pdf: 862690 bytes, checksum: 448d8bedc160b95654695c9900b1d0fe (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A aquisição de dados tem evoluído de forma significativa nos últimos anos e passa a ser indispensável em várias aplicações nas áreas de engenharia, agricultura, medicina, aeronáutica, etc. O estado da arte nessa área envolve o uso de sistemas de comunicação sem fio e da internet. Neste trabalho é apresentado um sistema moderno de aquisição de dados, que é baseado em uma comunicação sem fio via rede GSM (Global Mobile for System), com conexão via Internet através de um sistema de telefonia celular GPRS (General Packet Radio Service), monitoramento de dados via página Web (World Web Browser) e interface de aplicação com base em um microcontrolador. O sistema é bastante flexível e foi testado em operações reais no monitoramento de temperatura ambiente. Os resultados obtidos são altamente satisfatórios e mostra que o sistema pode servir de base para aplicações em diferentes áreas onde a telemetria seja indispensável. / Data acquisition has significantly been developed in the last years and became indispensable in many application area of engineering such as agriculture, medicine, aeronautic, etc. The state of art in this area is basead on wireless communication system and Internet. In this work it is presented a modern data acquisition based on wireless communication through the Internet, which includes a Celular Mobile GPRS (General Packet Radio Service) in a GSM (Global Mobile System) network, and remote data monitoring via WEB (World Web Browser) that can be used in a Telemetry Network construction. The system was tested in real conditions as a temperature monitoring system based on a microcontroller and it has presented good results. The high flexibility model proposed allows to use it in many distinct applications that require remote data acquisition.