Simulação de propagação de sinais de radiofrequência como metodologia de ensino em engenharia / Simulation of radiofrequency signal propagation as an engineering teaching methodology

Esse artigo descreve uma metodologia para o ensino de propagação utilizando um software de código fonte aberto, chamado PyLayers, que tem como objetivo facilitar o processo de aprendizado de conceitos de propagação indoor. Entretanto, não é comum que os discentes do curso de graduação em engenharia da computação e telecomunicações tenham algum contato com este tipo de software. Partindo dessa premissa, o estudo deste simulador proporciona ao aluno de engenharia, a oportunidade de se familiarizar com este tipo de ferramenta computacional. Além disso, a metodologia proposta será usada como um complemento aos métodos de ensino convencionais, ajudando alunos a consolidar os conceitos ensinados no curso e motivá-los a explorar conceitos relevantes sobre propagação através do aprendizado interativo. As tarefas de aprendizado usando a metodologia baseada no uso do software PyLayers foram divididas em quatro etapas: apresentação dos conceitos relativos a propagação indoor, visualização do código PyLayers, teste do código na linha de comando em linguagem Python e interatividade através de mapas de calor dos parâmetros apresentados pela teoria de propagação. Assim, ele complementa o ensino tradicional, melhorando a eficiência na aprendizagem e facilitando o entendimento, conforme verificado pela aplicação de um minicurso submetido aos alunos de engenharia da computação e telecomunicações. As métricas objetivas foram avaliadas para comprovar a eficiência no aprendizado

Evaluate and Optimise Wireless Communication Performance for Typical Buildings

It is predicted that mobile traffic, mainly taking place indoors, will increase up to 1000 times in the next decade. Future smart buildings/cities will be connected through wireless communication systems. High capacity and reliable wireless communications will play a very important role in future smart building/city. In telecommunications, a femtocell is a small, low-power cellular base station, typically designed for use in a home or small business. It allows service providers to extend service coverage indoors or at the cell edge, especially where access would be limited or unavailable. Since its first commercial deployment by Sprint Nextel Corporation in 2008, femtocell has continued to gain momentum with mobile network operators in America, Asia and Europe. Plenty of phone calls are placed indoor, and the technology is now deployed for residential and commercial use. But, so far, it is not well known how the wireless performance is related to building structures and material properties, and the building design process has not taken into consideration of wireless performance, resulting in poor wireless performance in some passive buildings. In this M.Phil. thesis, first, a set of wireless performance metrics is designed to measure the wireless performance in buildings; second, different building models focus on coverage and capacity are simulated and analysed to compare the influences of typical building structures; third, novel ways to improve building wireless performance will be investigated

Investigation of Indoor Propagation Algorithms for Localization Purposes: Simulation and Measurements of Indoor Propagation Algorithms for Localization Applications using Wall Correction Factors, Local Mean Power Estimation and Ray Tracing Validations

The objective of this work is to enhance the awareness of the indoor propagation behaviour, by a set of investigations including simulations and measurements. These investigations include indoor propagation behaviour, local mean power estimation, proposing new indoor path loss model and introducing a case study on 60 GHz propagation in indoor environments using ray tracing and measurements. A summary of propagation mechanisms and manifestations in the indoor environment is presented. This comprises the indoor localization techniques using channel parameters in terms of angle of arrival (AOA), time of arrival (TOA) and received signal strength (RSS). Different models of path loss, shadowing and fast fading mechanisms are explored. The concept of MIMO channels is studied using many types of deterministic channel modelling such as Finite Difference Time Domain, Ray tracing and Dominant path model. A comprehensive study on estimating local average of the received signal strength (RSS) for indoor multipath propagation is conducted. The effect of the required number of the RSS data and their Euclidian distances between the neighbours samples are investigated over 1D, 2D and 3D configurations. It was found that the effect of fast fading was reduced sufficiently using 2D horizontal’s arrangement with larger spacing configuration. A modified indoor path loss prediction model is presented namely effective wall loss model (EWLM). The modified model with wall correction factors is compared to other indoor path loss prediction models using simulation data (for 2.4, 5, 28, 60 and 73.5 GHz) and real-time measurements (for 2.4 and 5 GHz). Different operating frequencies and antenna polarizations are considered to verify the observations. In the simulation part, EWLM shows the best performance among other models. Similar observations were recorded from the experimental results. Finally, a detailed study on indoor propagation environment at 60 GHz is conducted. The study is supported by Line of Sight (LoS) and Non-LoS measurements data. The results were compared to the simulated ones using Wireless-InSite ray tracing software. Several experiments have confirmed the reliability of the modelling process based on adjusted material properties values from measurements