Active-Based Capacitive Coupling Circuit for Narrowband PLC Systems

Gustavo Gonçalves, Luis Guilherme da Silva Costa, Ândrei Camponogara, Marlio Jose do do Couto Bonfim, Moises Vidal Ribeiro

DOI: 10.14209/sbrt.2023.1570915031

Keywords: coupling circuit active filter power line communication

Abstract

Aiming to introduce new directions to improve the performance of narrow-band power line communication (PLC) systems in low-voltage electric power grids, this study introduces an active-based capacitive PLC coupling circuit for duplex communication. Simulations show that transmission and reflection parameters achieved good results while the Op-Amp provide a desired signal gain in the pass-band.

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Plastic Optical Fibres as Light Illuminators in Digital Fourier Transform Holography: Feasibility and Resolution Considerations

Ricardo Marques Ribeiro, Paulo Acioly Marques dos Santos

DOI: 10.14209/sbrt.2023.1570915058

Keywords: Digital Fourier Transform Holography Moiré Patterns Plastic Optical Fibres Profilometry

Abstract

This paper describes the use of step (SI), double- step (DSI) and graded-index (GI) PMMA-based Plastic Optical Fibres (POFs) as the light illuminators for the Digital Fourier Transform Holography. The POFs can generate holograms with contrast and resolution comparable to the case of direct illumination by using red color lasers. DSI-POFs enabled the generation of better interferometric moiré patterns than of SI- POFs despite the same geometrical transversal size. The GI-POFs can produce fringes with better contrast and less noise holograms, thus providing enough visibility/resolution for possible applications as holographic profilometry and non-destructive tests.

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Performance of SMD-LED Array for Visible Light Communications

Ricardo Marques Ribeiro, Bettina F. Cordoniz Buckingham Maia, Ivan Landerson das Chagas Pinheiro, Alexandre Castro de Toledo Santos, Vinicius Nunes Henrique Silva, Cláudia Barucke Marcondes

DOI: 10.14209/sbrt.2023.1570915071

Keywords: IoT Phototransistor VLC White LED

Abstract

In this work it is described a communication link with white light generated by an array of SMD-LEDs as the transmitter. A single phototransistor is used in the receiver. Effects of diffused light, color-temperature of lighting LEDs and field-of-view are investigated. Optical link tests were performed up to 2m distance in the OOK-NRZ pseudo-random digital modulation format.

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Rede Convolucional Deformável Aplicada a Sistemas de KWS Robusto ao Ruído

Ênio Silva, Rui Seara

DOI: 10.14209/sbrt.2023.1570915295

Keywords: Convolução deformável Detecção de palavras-chave Reconhecimento automático de fala Robustez ao ruído

Abstract

Este trabalho apresenta uma discussão sobre o uso de convolução deformável em sistemas de detecção de palavras-chave (keyword spotting - KWS) para operação em ambientes de baixa razão sinal-ruído (signal-to-noise ratio - SNR). A robustez ao ruído ainda é um problema crítico em aplicações de reconhecimento automático de fala do mundo real. Para mitigar esse problema, visando a obtenção de características discriminativas que descrevam melhor as pistas acústicas em cenários com baixa SNR, o uso de redes neurais convolucionais deformáveis (DefCNN) é considerado no processo de extração de características do sinal de fala. Resultados de simulação numérica são apresentados visando avaliar a acurácia do reconhecimento de palavras-chave, confirmando a eficácia do uso de DefCNN em aplicações de KWS.

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Frequency Response of a Fluorescent Fibre Detector Intended for Visible Light Communications

Ricardo Marques Ribeiro, Ivan Landerson das Chagas Pinheiro, Bettina F. Cordoniz Buckingham Maia, Maristela Ciara, Cláudia Barucke Marcondes, Vinicius Nunes Henrique Silva

DOI: 10.14209/sbrt.2023.1570915314

Keywords: Fluorescence Omnidirectional Light Collector Plastic Optical Fibre Visible Light Communications

Abstract

White LEDs can be simultaneously used for communication and illumination. This paper describes the frequency response of an omnidirectional light collector (OLC) made from fluorescent plastic optical fibres able to filter the slow luminescence from the phosphor coating of the LED. This OLC is useful for omnidirectional detection of modulated optical carrier in the visible spectrum. The OLC is intending to relax the mobility constraints of an optical wireless receiver.

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Análise Comparativa de Técnicas de Sensoriamento Espectral baseadas em Redes Neurais, Matriz de Covariância e Densidade Espectral de Potência

Wesley Silva, André Antônio Anjos, Rausley Adriano Amaral de Souza

DOI: 10.14209/sbrt.2023.1570915390

Keywords: Sensoriamento espectral cooperativo rádios cognitivos Rede neural artifical TV White Spaces

Abstract

Neste artigo será apresentada uma análise comparativa de desempenho de várias técnicas de sensoriamento espectral cooperativo e centralizado com fusão de dados, a saber: Gini index detector (GID), Pietra-Ricci index detector (PRIDe), generalized likelihood ratio test (GLRT), weighted circular folding cooperative power spectral density split cancellation (WCFCPSC) e uma rede neural artificial (RNA) DenseNet. A análise é conduzida em uma variedade de cenários, nos quais serão considerados canais seletivos em frequência, sombreamento espacialmente correlacionado, ruído uniforme e não uniforme e, também, ruído dinâmico. Por meio dessa análise, apresentam-se novas conclusões sobre as técnicas avaliadas, contribuindo para o avanço do conhecimento na área de sensoriamento espectral e fornecendo direcionamentos importantes para a escolha da técnica mais adequada em diferentes contextos.

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Coverage Estimation and Performance Analysis of 5G over Millimeter Waves

Vilmar Júnior, Luan Silva, José Miracy Filho, Dércio M. Mate

DOI: 10.14209/sbrt.2023.1570915402

Keywords:

Abstract

This paper aims to evaluate the performance of 5G over mmWave. Estimation of signal coverage in two bands, i.e., n260 (39 GHz) and n261 (28 GHz) in scenarios of Line-of-side (LOS) and Non-line-of-side (NLOS) is also provided. The results of this study attest to the higher sensitivity of mmWave 5G and show that, to ensure acceptable performance, indoor applications, e.g., picocells, whose coverage radius does not exceed 150m are recommended.

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A Fairer Comparison of Processing Implementations in User-Centric Distributed Massive MIMO Systems

Michael André Sousa Costa, Marx Miranda de Freitas, Thaissa Toyomi Rocha Ueoka, Daynara Dias Souza, André Fernandes, Andre Mendes Cavalcante, Roberto Menezes Rodrigues, Joao Weyl Costa

DOI: 10.14209/sbrt.2023.1570915442

Keywords: Cell-free massive MIMO computational complexity processing implementations user-centric approach

Abstract

This paper performs a new comparison between distributed and centralized processing implementations of user-centric distributed massive multiple-input multiple-output (D-mMIMO) systems, also known as cell-free mMIMO. The impacts of processing capacity limitations and inter-central processing unit (CPU) coordination are considered to perform a fairer comparison. The analysis includes two radio units (RUs) selection methods, varying levels of inter-CPU coordination, and different processing capacity restrictions. Simulation results indicate that processing capacity limitations affect spectral efficiency (SE) more in centralized implementations than in distributed ones. Moreover, centralized implementations may require more inter-CPU coordination to improve SE.

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Realistic Assessment of Spectrum Sensing for TV White Space Scenarios in Brazil: Insights for System Optimization

André Antônio Anjos, Dayane C. J. Martins, Rausley Adriano Amaral de Souza

DOI: 10.14209/sbrt.2023.1570915656

Keywords: TV White Spaces Spectrum Sensing Energy Detection ISDB-TB

Abstract

The need for ever-higher transmission bands in the most advanced telecommunications systems is primarily brought on by the growing traffic demand from new services and applications aimed at their consumers. These new systems are currently having trouble accessing the necessary bands because of a situation of spectral scarcity. However, the electromagnetic spectrum's physical constraints are only one cause of this scarcity; another is spectrum underutilization. Cognitive radios, which have spectral sensing capabilities, appear to be a solution to this underutilization issue. This paper assumes scenarios of transmission opportunities inside the TV White Space spectrum in Brazil to simulate and assess spectral sensing based on the energy detection technique. The implemented simulation considers the licensed users' use of an OFDM-like transmission signal in this frequency band, which has clearly defined and standardized features. Through the investigation of detection and false alarm probability, the study evaluates how effectively the spectrum sensing system performs in various circumstances.

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Circularly polarized device for 5G-NR applications on Industry 4.0

Paulo M Casmal, Gabriel Fré, Ricardo Franco, Rafael Abrantes Penchel, André Pantoja de Souza

DOI: 10.14209/sbrt.2023.1570915682

Keywords: circular polarization indoor application performance evaluation

Abstract

This work presents a 5G eMBB (Enhanced Mobile Broadband) device with a circularly polarized radio frequency front-end operating at 3.75GHz. This function enhances the system's reliability and versatility without being affected by its orientation or position. To achieve this goal, the study presents the design of a dual-polarized antenna array that is combined with a 90◦ hybrid coupler. The radiating structure of the antenna is then connected to a 5G eMBB commercial module, and practical results are obtained in terms of RSSI (Received Signal Strength Indication) and throughput using the circularly polarized radio interface. These results are then compared to the equivalent linear single polarization structure.

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