Smart grid aims at improving the efficiency, reliability, security, and quality of service (QoS) of the current electricity grid by exploiting the advances in communication and information technology. In parallel to size of the electricity grid, smart grid communication infrastructure should cover a very large geographical area that may extend from remote generation sites to densely populated residential regions and inside buildings, homes, and electricity-power-system environments. In such an extensive communication network, different communication technologies operating on different communication medium are likely to coexist. Among the communication technologies available, wireless and power line communication (PLC) based solutions are comparatively attractive especially considering cost of the initial investment required for the realization of a communication network with such an immense size. In this dissertation, a detailed investigation of wireless and PLC channel characteristics of the smart grid networks is presented. Among the topics discussed are the time variation characteristics of wireless channels, root-mean-squared (RMS) delay spread and path amplitude statistics of PLC channels, and the impact of impulsive noise on orthogonal frequency division multiplexing (OFDM) systems.

International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / Parameterized data from ARTM channel sounding test flights are used to derive a parameter-based estimate of the scattering function. The Doppler bandwidth and Doppler spread, important measures of channel dynamics, can be estimated from such a scattering function. Data collected from ARTM Flight 11 suggest that the Doppler bandwidth is larger than 6.7 Hz. Even for very small collections of parameterized data, surprising agreement is shown to non-parametric scattering function estimates. This confirms modeling assumptions and offers a way to achieve significant reductions of storage requirements.

International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada / In an effort to determine a more accurate characterization of the multipath fading effects on telemetry signals, the BYU telemetering group is implementing an inexpensive data acquisition system to measure these effects. It is designed to measure important signals in a diversity combining system. The received RF envelope, AGC signal, and the weighting signal for each beam, as well as the IRIG B time stamp will be sampled and stored. This system is based on an 80x86 platform for simplicity, compactness, and ease of use. The design is robust and portable to accommodate measurements in a variety of locations including aircraft, ground, and mobile environments.

Ultra-wideband (UWB) communication has been the subject of extensive research in recent years due to its unique capabilities and potential applications, particularly in short-range multiple access wireless communications. However, many important aspects of UWB-based communication systems have not yet been thoroughly investigated. The propagation of UWB signals inside very small enclosed environments is one of the important issues with significant impacts on the future direction, scope, and generally the extent of the success of UWB technology. The objective of this thesis is to obtain a more thorough and comprehensive understanding of ultra-small UWB channels for communication applications and design issues for enhancing the data rate of UWB systems. This works supports the postulation of a high capacity UWB wireless interconnect scheme for communicating devices within conducting enclosures – a wireless “backplane”. This thesis proposes the use of an Ultra-Wide Bandwidth (UWB) ultra-small scale wireless interconnect scheme for use within electrically small enclosures. Such ultra-small environments (size ≤ 10 wavelengths) are topologically much more complex, being more cluttered, than typical indoor environments (size ≥ 10 wavelengths). The concept is presented through two different scenarios. Firstly, a PC Tower case is presented as a model environment and the work seeks to present the optimum channel performance, where EMI issues are discussed and problem avoidance proposed. Secondly, in order to extrapolate the different results from the study inside the PC, an investigation is carried out using an Aluminium tower case as a more generic model environment. The analysis is based on the behaviour of box modes within a conducting resonator enclosure and the effective communications bandwidth for UWB systems for different sizes and components within. From these general considerations the research presents theoretical and experimental results from which are derived the communications metrics measured within enclosures. Simulations of the different scenarios are performed using different techniques such as ray tracing and a full wave model, based on CST Microstripes. Empirical data is recorded using a vector network analyser (VNA)-based wideband channel sounding system where channel measurements are carried out in every scenario regarding different aspects such as frequency response and time domain analysis, evaluation of the channel capacity, power delay study and the nature of the environment.

[pt] Este trabalho tem como objetivo caracterizar o canal de radiopropagação móvel a partir de resultados das medições realizadas nas faixas de 2.5 GHz e 3.5 GHz em ambiente urbano. Para alcançar tal objetivo, será utilizada a técnica de sondagem em frequência de multiportadoras, utilizando modulação OFDM e as técnicas de filtragem de perfil de retardos de potência CFAR e/ou CLEAN para identificar os multipercursos válidos. Após o processo de filtragem e processamento dos dados, será feita a comparação dos parâmetros recomendados pela recomendação ITU-R P.1411-6 validando os resultados encontrados e também gerando novos parâmetros nas faixas de 2.5 GHz e 3.5 GHz, dentro das condições de especificações das medições realizadas. / [en] This work aims to characterize the mobile radio propagation channel according to the results of the measurements in the ranges of 2.5 GHz and 3.5 GHz in an urban environment. To achieve this goal, we will use the frequency multicarrier sounding technique, using OFDM modulation and power delay profile (PDP) filtering techniques CFAR and CLEAN to identify valid multipath. After the filtering process, the comparison will be made of the parameters found with the ITU-R P.1411-6 validating the results and also generating new parameters in the ranges of 2.5 GHz and 3.5 GHz, within the terms of specifications of measurements.

[pt] O correto planejamento de novas redes de comunicação sem fio de voz e dados representa um grande desafio ao incluir serviços cada vez mais avançados com diferentes requisitos de qualidade, suporte a mobilidade, altas taxas de transmissão e capacidades de tráfego elevadas. Os ambientes nos quais estas redes operam são dos mais diversos e contemplam desde na áreas abertas até centros urbanos com alta densidade de edificações. O presente trabalho apresenta resultados experimentais que permitem caracterizar o canal de radio-propagação num ambiente urbano com mobilidade do receptor. Como resultado de campanhas de medições, são identificados modelos do canal que permitem ao projetista da rede definir a melhor configuração de parâmetros e critérios de projeto para a implantação de uma rede móvel de acesso sem fio em banda larga. As medições foram realizadas nos bairros da Gávea, Leblon e Lagoa, no Rio de Janeiro, com estação transmissora instalada na PUC-Rio (prédio LEME) na frequência de 3,5 GHz, destinada para novos serviços móveis. Os principais resultados obtidos são: o desenvolvimento de uma metodologia de medição simples e precisa, utilizando a técnica OFDM, e das ferramentas de software para pré-processamento e analise de dados; o desenvolvimento de modelos semi-empíricos para a previsão da perda média de propagação; a obtenção de perfis de retardo do canal e dos valores médio e desvio padrão do retardo em condições de visibilidade (LOS) e obstrução (NLOS), e de expressões empíricas para sua estimativa; a obtenção do valor médio das amplitudes relativas dos multipercursos e sua modelagem em função do valor de retardo relativo. / [en] Best practices of radio planning for new wireless networks with mixed trac of voice and data are a big technical challenge due to the need to provide of advanced services with different quality requirements, high data throughput, mobility and high traffic demands. Environments for operation of this kind of networks are diverse and include open areas with low population density as well as urban centers. This thesis presents experimental results obtained to characterize the wideband radiopropagation channel on urban environments with a mobile receiver. The analysis of measured data allows the identification of channel models and propagation mechanisms needed for the design engineer to define the best parameter configuration and project criteria in the deployment of a wideband mobile wireless network. The measurement campaign was executed on Gavea neigborhood in Rio de Janeiro city with a transmitter station located in a PUC-Rio university building (Lcme Building) operating at 3,5 GHz, frequency used for the new wideband mobile services. The main results are: the development of a simple and precise methodology for measuring, using the OFDM technique OFDM, and the software tools for pre-processing and analysis; the development of semi-empirical models for predicting the average propagation loss in the urban environment; measurements of multipath delay profiles of the channel and the average values and standard deviation of the RMS delay spread in visibility (LOS) and obstruction (NLOS) conditions, and derivation of empirical expressions for their estimation; measurements of the average values of multipath amplitudes its modeling in function of the relative delay.

[pt] Este trabalho consiste de um estudo do comportamento de sinais de rádio propagando-se em um ambiente móvel celular com características urbanas. Este estudo é dividido em duas partes: realização de medidas de cobertura e análise dos dados obtidos. Na primeira parte, uma portadora em 900MHz, sem modulação, é transmitida. Um laboratório móvel, especialmente montado para este trabalho, é utilizado para medir e armazenar o valor instantâneo da potência do sinal recebido. Na segunda parte, realiza-se análise dos dados. Determina- se o valor médio do sinal e sua variabilidade. No estudo da média do sinal, faz-se uma análise comparativa entre os resultados medidos e as predições de modelos de cobertura propostos. Observa-se como estes modelos se adequam à região em questão, escolhida devido às suas características de relevo bastante acidentado. O estudo da variabilidade do sinal ao redor do seu valor médio é feito considerando-se as componentes lenta e rápida do sinal recebido separadamente. As características estatísticas da componente de desvanecimento lento são comparadas com o modelo de distribuição Log-normal. Para as estatísticas da componente de desvanecimento rápido são feitas comparações com as distribuições de Rayleigh e de Rice, neste caso quando existe linha de visada entre transmissor e receptor. Os resultados, sumarizados nas conclusões do trabalho, apresentam aspectos interessantes bem diferentes dos resultados encontrados na literatura. Sempre que possível, justificativas para estas são diferenças são propostas. / [en] This thesis presents a study of propagating radio signals through a cellular mobile urban environment. The study is divided on two parts: a measurement campaign and collected data pocessing and analysis. On the first part, a 900 MHZ carrier without modulation is transmitted. A mobile station, specially built for this work, collects and stores the instantaneous value of the receiving power signal. On the second part, all the data processing and analysis is accomplished. The study concentrates on the signal mean value over a sector of few wavelengths and its variability. The measured mean value compared with those obtained by the most used coverage models. The adequacy of the models from these very peculiar topography region is determined. The study of signal variability is done separating the fast and slow components of the received signal. The statistics of the slow fading component is compared with the assumed log- normal distribuition. For the statistics of the fast fading components, comparisons with Rayleigh and Rice distribuitions are made. The results, summarised on the conclusion, present very interessing aspects different from those on the literature. Whenever is possible, expalnations for these differences are proposed.

The means of communication in oceanic environments is currently dominated by sonar. Although it is reliable for long-distance transmission, the vision of internet of underwater things (IoUT) requires an alternate means for high-data-rate transmission. It is also envisaged that a networked underwater and above-water objects, such as sensor nodes, and autonomous underwater vehicles will benefit seafloor exploration. The use of laser-based optical communication is poised to realize this dream while working hand-in-hand with acoustic and radio-frequency technologies from the littoral zone to deep blue sea. While blue and green lasers are typically utilized depending on the optical properties of the water, laser-based white light is attractive in a number of aspects. In this thesis, we proposed and realized the use of white light to model the channel and to provide the immediate decision for the preferred system configuration, which is critical for developing reliable communication links, particularly, in the presence of turbulence, which makes the alignment of underwater wireless optical communication (UWOC) links challenging. Temperature and salinity changes are among factors that change the refraction index, giving rise to beam wander. This thesis explores the dependence of underwater turbulence on the wavelength. After comparing the performance of red, green, and blue lasers, an ultra-fast comprehensive method that utilizes a white-light source that can produce a wide range of wavelengths is implemented. Experimental results show an 80%-decrease in the scintillation index as the wavelength is increased from 480 to 680 nm in weak turbulence caused by a 0.02-℃/cm temperature gradient with a 40-ppt salt concentration, which emulates conditions found in the Red Sea. The effect of turbulence on the bit error ratio (BER) is also investigated experimentally. Temperature gradients increased the BER especially for shorter wavelengths. The results along long-transmission distances were verified using Monte Carlo simulations. The correlation matrix between wavelengths was studied, which is important for designing multiple-input multiple-output systems. The results obtained show that as the difference in the wavelengths increases, the correlation decreases. Based on the interplay among scintillations, scattering, absorption, and the correlation between different wavelengths, it is possible to design a more reliable UWOC link.

Because broadband wireless systems benefit from accurate channel characterization, there is growing interest in broadband wireless multiple-input multiple-output (MIMO) channel models. This thesis verifies the suitability of the Saleh Valenzuela with Angle (SVA) model for wideband MIMO communication models. While recent wideband MIMO measurements have been obtained by switching a single transmit/receive pair over all possible antenna pair combinations, a simultaneous probing system is superior because of the time required for the antenna-switching channel measurements. This work provides two different wideband channel estimation algorithms based on simultaneous transmission from and reception on all antennas. Simulated data from an electromagnetic ray tracing tool is used (as a substitute for measured data) to obtain propagation data. One of the wideband estimation algorithms is then used to extract MIMO channel data from propagation data. From these estimated channels, parameters such as capacity, coherence bandwidth, RMS delay spread and maximum delay spread are compared (statistically) to those obtained from the SVA model. The comparisons of the different parameters show the ability of the SVA model to simulate wideband MIMO communication channels.

No description available.