XXXI Simpósio Brasileiro de Telecomunicações

This paper presents a modification to the ICA-MAP algorithm in order to improve its convergence. It was observed through testing that it is possible to limit the magnitude of the gradient vector, used to estimate the denoising model, and thereby improve the stability of algorithm. Such adaptation can be understood as a restriction the original...

In a recent paper, we have proposed a new lowcost framework for the construction of meteorological radars, by using two fixed widebeam antennas. In this work, we present the design of an optimal detector for this new kind of radar. The detector is designed according to the Neyman-Pearson criterion, based on the likelihood ratio of the signals...

When spatial multiplexing (SM) technique is applied to a cellular system, the performance is affected by the interfer- ence from neighboring co-channel cells. This paper investigates and compares the performance between SM and non-SM systems in a noise-limited and interference-limited environment, where parameters related to the transmit power and...

A new Hidden Markov Model (HMM) for burst errors is proposed. This model is based on a compact representation of the error sequence in terms of succeeding pairs of clusters and gaps lengths. Its Markov chain has two classes of states associated to the generation of gaps and clusters lengths, respectively. The proposed model may be characterized by...

Shortened and lengthened systematic Luby Trans- form Codes (LT-codes) have been shown, in this paper, to perform better than their equivalent mother codes by simulating trans- mission of LT-coded information over a binary erasures channel. The performance is improved as the shortening (lengthening) factor is increased while reducing (keeping) its...

Some types of Delay and Disruption Tolerant Networks (DTNs) need of humans help to send data between users. However, humans are socially selfishness and prefer to help users with whom they have a social relationship, fact that affects the network performance. Given the limited memory secondary space in the devices, the buffer management becomes a...

This article proposes an architecture for an ISP (Internet Service Provider) utilizing SDN-OpenFlow. With this, we attempt to create a network with less equipment processing and more traffic engineering potentiality than today’s one, and at the same time without the problems that might exist in networks implemented with OpenFlow, as controller overload,...

This work proposes a new approach to powering PON extenders using the fiber powering technique, in order to make them virtually passives. In our demonstration, we show the feasibility of this technique applied to an SOA based extender for XG-PON/G-PON shared network reaching a distance of 50 km with a split ratio of 1:32. Results regarding the...

This work addresses a method of eliminating blind zones and range ambiguity in monostatic pulsed radar systems. It is employed a combined use of Noise Radar (transmitted signals characterized by stochastic processes) and random pulse repetition frequency (PRFs). Finally, a comparison between the proposed method and conventional systems method -...

This work proposes and conduct a practical investigation on the a probability density function of the α-µ/Gamma composite distribution, obtained in closed-form expression, for the multipath shadowed fading channel in wireless environments. The statistical characterization includes both theoretical models and practical investigations through field...