XXXVIII Simpósio Brasileiro de Telecomunicações e Processamento de Sinais

Image restoration aims to attenuate distortions caused in the acquisition process. In this paper, we use a residual convolutional neural network to restore colored images which were degraded by a Gaussian point spread function. As cost function, we consider the mean square error, and a function based on the structural similarity (SSIM) index. By means of...

In this article we show that the time for changing states in electromechanical relays can generate random values. We use this phenomenon to generate seeds for linear feedback shift registers (LFSR). We created in FPGA a circuit derived from LFSR that generates 10^6 binary vectors per second with non-linear sequence. Statistical tests reveal confidence in...

Este trabalho apresenta uma análise experimental da coexistência entre os sinais 5G NR (5G New Radio) e LTE-A (Long-Term Evolution Advanced) em sistemas FiWi (Fiber/Wireless). O sistema proposto é composto por uma unidade central 4G/5G, um fronthaul móvel óptico de 12,5 km e uma unidade de rádio remota (RRU - Remote Radio Unit). As análises de desempenho...

The QAM-FBMC system have been a promising alternative to the OFDM for attempt the needs of 5G communication systems. Unlike for OFDM systems, does not exist a specific prototype filter for the QAM-FBMC system, thus, its performance is changeable related to the applied prototype filter. The bit error rate parameter is usually used to evaluate the...

In this paper, we investigate the Block Error Rate (BLER) performance of a Convolutional Neural Network (CNN)- based autoencoder as a self-learning communication system under a generalized fading condition. To this end, the α-µ model is chosen, both for its flexibility and applicability to practical fading scenarios. For comparison and consistency...

This paper presents a method of change detection in ultrawideband (UWB) very high frequency (VHF) synthetic aperture radar (SAR) images, using the data analysis tool, robust principal component analysis (RPCA) via principal component pursuit (PCP). In this context, the proposed method considers stacks of SAR images to explore data diversity. For...

As transmissões de dados sem fio em canais variantes no tempo e com alta dispersão Doppler são desafiadoras. Assim, foi proposta a modulação Orthogonal Time-Frequency Space (OTFS) que apresentou vantagens significativas em canais duplamente dispersivos. O modelo de canal na modulação OTFS é esparso, permitindo usar algoritmos de baixa complexidade para...

Este trabalho apresenta a avaliação de desempenho de uma máscara binária variante no tempo, cuja finalidade é a redução do tempo de detecção de emissões otoacústicas evocadas por estímulo transiente (TEOAE). As variações das características espectrais intrínsecas da TEOAE foram utilizadas para configurar os parâmetros da máscara binária de forma a...

Several prediction models and digital signal processing techniques have been developed for HF communication, especially the ALE technique, but there is still no standardized method for determining frequencies. In addition, there is a need to ascertain the impact on HF links of peculiar disturbances that happen in the ionosphere in Brazilian territory,...

The task of obtaining the performance of a communications receiver is difficult, since it involves the implementation of the physical layer transmission and reception chains and also requires great computational time, since Monte Carlo methods make up the base of link-level simulations. The DVB-RCS2 standard provides some receiver performance data which...