XXXI Simpósio Brasileiro de Telecomunicações

Spectrum Sensing is studied to determine if a signal, measured by a cognitive user in an AWGN channel, results from the primary user or if is composed by noise one. The proposed method for spectrum sensing is based on normality tests. The results of Monte-Carlo simulations indicate that it is possible to identify transmission opportunities through...

Digital video presents a great challenge for any entity responsible for its archival: huge amount of data to be stored. This paper presents an empirical research that was conducted aiming to evaluate the introduction of the transcoding technique and the H.264/AVC encoding to the video archival system maintained at Brazilian Senate. Image quality...

In this contribution, the heuristic continuous ant colony optimization (ACO) algorithm is deployed to solve the energy-efficiency (EE) optimization problem in multirate multiprocessing gain (MPG) DS/CDMA network. The EE design deal with quasi-concave energy efficiency function, allowing the system to operate in the maximal energy efficiency point....

This paper descirbres the design of a real time monitoring system based on wireless sensor networks aiming to measure accelerations, airspeed, spacial orientation and geographical position of a radio-controlled aircraft in order to allow their designers (university students) to measure how their planes performed. We use a Microsoft .NET Gadgeteer board...

Apresentam-se resultados experimentais de reuso de portadora óptica para possíveis aplicações em redes de acesso ópticas. A portadora, inicialmente modulada em altas taxas (sinal downstream, < 50 Gb/s) foi remodulada em 3,8 Gb/s (sinal upstream ). A técnica de reuso é baseada na saturação do ganho de um amplificador óptico a semicondutor ultra-longo...

Wallace A. Martins, Leonardo O. Nunes, Diego B. Haddad, Luiz W. P. Biscainho, Markus V. S. Lima, Maur´ıcio do V. M. da Costa, Bowon Lee.

Cognitive Radio, cooperative sensing, spectrum sensing, mobile communication systems

This paper describes a testbed prototype implemented with the WaveRunner transceiver card and the VisSim/Comm software for the purpose of spectrum sensing, as an alternative to the commonly-adopted solutions based on the USRP & GNU Radio. The testbed applies the energy detection in a data fusion, centralized cooperative spectrum sensing with up to...

This article presents a Baseband implementation proposal for LTE eNodeB. The hardware solution is based on a chipset with one FPGA Xilinx Virtex6 XC6VLX240T and one general purpose processor Intel i7. This work is focused on the firmware development for the physical layer using the FPGA device. Implementation aspects, validation strategy...

The importance of the traffic control is a huge paradigm on the Internet. The AS by definition assumes no external control, this could be an enourmous problem when the traffic is asymmetric and the inbound is the higher portion. The problem is very often in networks hosted in South America countries because their high level dependence to North American...