XXXVII Simpósio Brasileiro de Telecomunicações e Processamento de Sinais

Physical-layer security techniques have proven to be a good alternative to the computational high-cost traditional security mechanisms for wireless communications. In this work, the secrecy level provided by a Tomlinson-Harashima precoder is evaluated in a scenario in which the eavesdropper is allowed to perform extra signal processing at the received...

Analytical and experimental investigations considering indoor wave propagation and antenna diversity are presented for passive UHF RFID systems. Modelling results are reported for two-ray and three-ray reflection models, with the effect of floor and ceiling relative permittivity discussed. A novel multi-LOS multi-ray reflection model, considering...

This work presents an analysis of the design and operation of a receiver for visible light communication systems based on the OOK-M-FSK modulation. The functional blocks of the circuit are presented, as well as the demodulation algorithm for the studied VLC signal. Experimental results shown the proper operation of the circuit and the algorithm, since...

Este artigo apresenta uma plataforma de medição do diagrama de irradiação de antenas de microondas utilizando dois motores de passos, com seus passos e direções de rotações remotamente controladas por um transmissor infravermelho, através de um módulo receptor integrado ao Arduino. Este protótipo amplia o conjunto de grandezas de medidas, possibilitando...

The main objective of this project is the development of a tool that allows the universalization of the knowledge of signal processing in telecommunications through the study of image resolution in a playful and iterative way. It is intended to mount a prototype controlled by Arduino capable of printing images in different bit codes that allow to...

Aplicações de cadeias de blocos para redes privadas permitem o uso de mecanismos de consenso baseados em votação, pois possuem menor custo computacional quando comparados à prova de trabalho. Contudo, mecanismos de consenso baseados em votação exigem uma elevada troca de mensagens na rede, já que o número de mensagens cresce com o aumento do número de...

Este trabalho tem como objetivo o estudo de um algoritmo de quantização para a geração de chaves de criptografia a partir da informação do canal, avaliando-o em relação a sua capacidade de acordo de chave, número de bits gerados e sua aleatoriedade.

In this work, in order to model network traffic processes, an efficient multifractal model is proposed based on fewer parameters than other models present in the literature. The MEV model (Exponential Modeling for the multipliers' Variance) is based on a multiplicative cascade in the wavelet domain capable of synthesizing communication networks traffic...

This work presents a device and method for estimation and analysis of transient evoked otoacoustic emissions (TEOAE). The proposed method consists on an active noise canceller, based on the NLMS adaptive filter, which applies a noise-environment reference-signal acquired by an external microphone which is incorporated into the stimulation probe. The aim...

In this paper, the problem of joint downlink (DL) and uplink (UL) channel estimation is adressed in a multiuser multiple-input multiple-output (MIMO) wireless communication system. We consider that the known training sequence sent by a multiple-antenna base-station (BS) is received by single-antenna mobile stations (MSs) and then reported back to the BS...