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1 TECHNICAL SESSIONS PROGRAM August, 18th Monday 09h - 11h am YELLOW AUDITORIUM - Speech Processing I Speech Intelligibility Measures for Speech Enhancement under Nonstationary Acoustic Noise Tavares, Rodrigo (Instituto Militar de Engenharia, Brazil); Zão, Leonardo (Instituto Militar de Engenharia, Brazil); Coelho, Rosângela Fernandes (Instituto Militar de Engenharia (IME), Brazil) Abstract: This paper presents the study of four objective intelligibility measures to evaluate the performance of speech enhancement techniques. The objective measures have high correlation with the speech intelligibility rates obtained in subjective listening tests. Four noise reduction algorithms are applied to enhance the speech signals corrupted by real highly nonstationary acoustic noises. The results show that, for most of the noise conditions, the best intelligibility results are obtained by the speech enhancement technique based on the empirical mode decomposition. Moreover, the Wiener filtering based technique also achieves interesting intelligibility gain for the highly nonstationary noises. Nonnegative factorization of sequences of speech and music spectra Ramírez, Miguel Arjona (University of São Paulo, Brazil) Abstract: Speech source separation from mixtures with music signals is performed by means of nonnegative matrix factorization (NMF). The magnitude of the short-term Fourier transform (STFT) is used with the Kullback-Leibler divergence (KLD) while its power spectral density is applied with the Itakura-Saito divergence (ISD). Source separation is performed in the synthesis phase by factorization with compound bases using unsupervised NMF while the bases may be exemplar spectra randomly selected in an unsupervised manner or iteratively approached by a supervised factorization. Speech is represented four times more densely than music in the supervised case and almost six times more in the unsupervised case. The performance of the bases obtained in supervised NMF is proven to be far superior to the exemplar bases, selected in an unsupervised procedure. Also, the quality of the separated speech signal obtained by NMF with KLD clearly exceeds that of the speech signal delivered by NMF with ISD.

2 Objective Quality Assessment of Echo-Impaired Full-Band Speech Signals Ávila, Flávio (UERJ, Brazil); Nunes, Leonardo (Federal University of Rio de Janeiro, Brazil); Biscainho, Luiz W. P. (Federal University of Rio de Janeiro, Brazil); Tygel, Alan (UFRJ, Brazil); Lee, Bowon (Hewlett-Packard Laboratories, USA) Abstract: This paper describes a double-ended objective quality assessment method for evaluating full-band (sampled at 48 khz) speech signals impaired by acoustic echo and background noise. The proposed method is based on a single metric of the ITU-T standard PEAQ (originally developed for audio signals) that, along with an appropriate mapping function, is shown to be able to reliably predict the overall quality of speech signals concurrently degraded by acoustic echo and background noise. In order to train and validate the proposed method, three speech signal databases were developed and subjectively assessed. One database is used only for training and testing purposes whereas the other two are employed in validation. Using the validation databases, it has been shown that the proposed method can predict the quality of signals degraded with a wider scope of acoustic echo and noise characteristics than those considered in its development. PNCC features and FNN - MAP compensation techniques for continuous speech recognition Arcos Gordillo, Christian (Pontifical Catholic University of Rio de Janeiro, Brazil); Alcaim, Abraham (Cetuc/puc-Rio, Brazil); Mattoso Maia, Marco Antonio Grivet (Pontifical Catholic University of Rio de Janeiro, Brazil) Abstract: One of the biggest challenges in the area of continuous speech recognition is the signal degradation due to adverse conditions. The authors propose a histogram mapping followed by a filter through neural networks, in order to minimize the misfit caused by noise insertion in the speech signal. These methods are based on the compensation of attributes. An Extension To Fisher Linear Semi-Discriminant Analysis For Speaker Diarization Montazzolli, Sergio (Federal University of Rio Grande do Sul, Brazil); Adami, André G (University of Caxias do Sul, Brazil); Barone, Dante (UFRGS, Brazil) Abstract: The Fisher Linear Semi-Discriminant Analysis is used in Speaker Diarization to project acoustic features into a discriminant and lower dimensional space. Given that such analysis uses short segments to estimate the scatter matrices, the projection could be improved by using longer segments (i.e., more information). Since a change of speaker is more likely to occur during periods of non-speech, we propose to use segments of speech produced by the boundaries estimated from a voice activity detection method based on Hidden Markov Models. Using datasets from the NIST

3 Speaker Recognition Evaluations, we show that the estimated segments provide a better scatter matrices for the analysis. The results show a relative improvement of 21% in the Speaker Error Time on the Switchboard corpus used in the evaluations. Improvements in Blind Source Separation of Anechoic Underdetermined Speech Mixtures Pires, Jorge Costa (UFRJ, Brazil); Petraglia, Mariane R (Federal University of Rio de Janeiro, Brazil) Abstract: The DUET and TIFROM are the most widely used algorithms for separating anechoic mixtures in the underdetermined case (when the number of sources is larger than the number of sensors). Whereas the DUET algorithm requires that the sources are disjoint in the time-frequency domain, the TIFROM considers that there are regions in the time-frequency domain where the mixtures contain only one active source. Since both conditions are not always met in real scenarios, in this work two new algorithms are proposed such as to obtain good estimates of the attenuation and delay coefficients of each mixture without making use of such restrictions. The proposed methods employ binary masking, recursive estimates of the coefficients and sparsifying transforms in order to obtain improved solutions RED AUDITORIUM - Wireless Networks Techno-economic evaluation of wireless access technologies for campi network environments Moreira, Lilia (Instituto de Pesquisas Tecnologicas do Estado de Sao Paulo, Brazil); Zucchi, Wagner (Escola Politécnica - University of São Paulo, Brazil) Abstract: The widespread use of wireless access networks caused a rapid and continuous growth of this segment under telecommunications industry by democratizing the use of wireless embedded devices what drives organizations to deploy this type of access into their network environments. It is critical that organizations obtain relevant technical and economic knowledge to support their decision-making process towards identifying the technological option with the best technical and economic feasibility. The aim of this work is to develop a technoeconomic evaluation method for Wi-Fi, WiMAX and Mobile Networks. The evaluation targets campi network environments and consists of two criteria: the technical parameter that estimates the cell coverage and capacity and the economic parameter that estimates the costs for Capital Expendures (CAPEX) and Operational Expendures (OPEX). Additionally, the proposed evaluation method is applied to a case study for a public university campus located in the city of São Paulo. The contribution of this work is to present a techno-economic evaluation method of wireless access technologies for

4 campi network environments, and which considers Brazilian market conditions given this segment is expanding in Brazil. Power-Rate Control in Multirate Multiple Access Networks via Heuristic Ant Colony Optimization Marques, Mateus (State University of Londrina, Brazil); Ciriaco, Fernando (State University of Londrina, Brazil); Abrão, Taufik (State University of Londrina, Brazil) Abstract: In this paper, continuous heuristic ant colony optimization (ACO$_\mathbb{R}$) procedure is deployed to solve the power-rate optimization problem in multirate multi-processing gain (MPG) DS/CDMA networks. The power-rate allocation design is formulated as a special case of generalized linear fractional problem (GLFP), allowing the multiple access system to operate under best power-rate trade-off operation point. Numerical results considering realistic wireless mobile channels and system operation conditions have been shown the applicability of the ACO$_\mathbb{R}$ heuristic approach in order to solve this hard problem with practical interest in real energy-efficient, spectral-efficient CDMA systems, as well as of paramount interest in establishing the next wireless generation green communication networks. Analysis of Interference Alignment for Wireless Communication with External Interference Normando, Paulo G. (Federal University of Ceará, Brazil); Bandeira, Carlos Igor Ramos (Federal University of Ceará, Brazil); Moreira, Darlan C. (Federal University of Ceará, Brazil); Freitas, Walter (Federal University of Ceará, Brazil); Silva, Yuri C. B. (Federal University of Ceará, Brazil); Cavalcanti, Francisco R. P. (Federal University of Ceará, Brazil) Abstract: In order to better cope with the increasing levels of interference in wireless cellular systems, interference mitigation techniques that consider a certain degree of coordination/cooperation among cells have been recently employed, such as Joint Processing (JP) and Interference Alignment (IA). In this paper we evaluate the performance of different IA-based algorithms in the presence of uncoordinated external interference, with JP schemes used as a benchmark.sum rate and BER results are presented for different external interference scenarios and it is shown that there is trade-off between IA and JP, and that for high external interference levels IA algorithms modified to handle this external interference can achieve better performances.

5 Throughput of Wireless Networks with Poisson Distributed Nodes Using Location Information Nardelli, Pedro Henrique Juliano (University of Oulu, Finland); M. de Lima, Carlos H. (University of Oulu, Finland); Alves, Hirley (University of Oulu, Brazil); Cardieri, Paulo (University of Campinas, Brazil); Latva-aho, Matti (UoOulu, Finland) Abstract: This paper provides a statistical characterization of the individual achievable rates and the spatial throughput of bipolar Poisson wireless networks. We derive closed-form expressions for the probability density function of the achievable rates under two decoding rules: treating interference as noise, and jointly detecting the strongest interfering signals treating the others as noise. Based on these rules and the bipolar model, we approximate the expected maximum spatial throughput, showing the best performance of the latter decoding rule. We show that, when the same decoding rule and density are considered, the cognitive spatial throughput always outperforms the other option. A Cooperative Approach for Dynamic Spectrum Access in Radar Bands Junior, Carlos (Federal University of Rio de Janeiro, Brazil); Paisana, Francisco (Trinity College, Ireland); de Rezende, José F. (Federal University of Rio de Janeiro, Brazil); DaSilva, Luiz (Trinity College, Ireland) Abstract: The considerable amount of spectrum reserved but underutilized by radar systems has motivated several regulatory bodies to make Dynamic Spectrum Access (DSA) in radar bands a reality. Taking into account the incumbents' very long ranges, one of the main issues of DSA in these bands is the aggregate interference, derived from multiple CRs operating in the same channel. In this paper, we assess the impact of this phenomenon when spectrum sharing is performed in a totally opportunistic manner, for instance, when Dynamic Frequency Selection (DFS) developed by the IEEE h standard is employed, and when there is a cooperation mechanism between radar systems and CRs. We considered the operating characteristics of a real C band meteorological radar system with acceptable levels of interference standardized by the International Telecommunication Union (ITU). Geographic routing by using Location Algorithm based in Signal Measurements Ferreira, Luiz Carlos Branquinho (Federal Institute of Education, Science and Technology of south Minas Gerais, Brazil); Cardieri, Paulo (University of Campinas, Brazil); Branquinho, Omar C (Catholic University Campinas, Brazil); Tortorelli de Faria, Thiago (Puc-Campinas, Brazil) Abstract: This work proposes a geographic routing for wireless sensor networks, where the position of the sensor nodes is found through the use of a location algorithm based

6 on RSSI values. The goal is that the proposed protocol creates a sensor network map by analyzing the conditions of the work environment, since the RSSI values are directly affected by the conditions that act on the radio signal. The protocol was simulated, implemented in a real WSN and its functionality was evaluated and compared with another existing technique in the literature. GREEN ROOM - Optical Communications I Energy transmission in optical device makes for association of nonlinear directional coupler cascading Rodrigues Araújo, Antonio Alan (Universidade Federal do Ceará, Brazil); Oliveira, Antônio (Universidade Federal do Ceará, Brazil); Timbó, Átila (Instituto Federal do Ceará, Brazil); Bezerra Martins, Francisco (Universidade Federal do Ceará, Brazil); Nascimento, José (Federal University of Ceará, Brazil); Fraga, Wilton (Instituto Federal do Ceará, Brazil) Abstract: We present a numerical study of optical signals propagation and switching by using cascaded nonlinear directional couplers based on photonic crystal fibers (NLDCPCF). We have explored the device's potential for energy switching by changing the input power for the use of modulated pulses with PAM-ASK. With pulses temporal width of 100 fs, we have considered the influence of high order dispersion effects such as third order dispersion. We have considered too the nonlinear self-steepening, intrapulse Raman scattering and self-phase modulation effects. We have analyzed the device's transmission of energy efficiency with pump power around the critical power Exhaustive Gaussian Approach for Performance Evaluation of Direct-Detection OFDM Systems Employing Square and Cross QAM Cruz, Pedro (Instituto de Telecomunicações, Instituto Superior Técnico, Portugal); Rosário, João (Instituto de Telecomunicações, Portugal); Alves, Tiago (Instituto de Telecomunicações, Portugal); Cartaxo, Adolfo (IST-TUL, Portugal) Abstract: An exhaustive Gaussian approach (EGA) is proposed to evaluate, through numerical simulation, the bit error ratio (BER) of direct-detection orthogonal frequency-division multiplexing systems employing square and cross quadrature amplitude modulation. Excellent agreement between the BER estimates from the direct error counting (DEC) and the EGA is shown for different levels of optical signalto-noise ratio and signal distortion. It is shown that the EGA requires about three orders of magnitude less in computation time than the DEC method for BER levels around 10$^{\text{-6}}$, with the difference getting higher for lower BER levels.

7 Signal Predistortion for Nonlinear Transmitters in Direct-Detection OFDM over Multimode Fibers Vasconcelos, Celio K H (University of Brasilia, Brazil); Barreto, Andre N (University of Brasilia (UnB), Brazil); Mello, Darli (University of Campinas (UNICAMP), Brazil); Simões, Fábio D. (CPqD, Brazil) Abstract: This paper investigates the transmission of OFDM signals, generated by a directly-modulated VCSEL, over an optical channel estimated from experimental measurements in OM-3 multimode fibers. Simulation results indicate limitations on the system performance due to the nonlinear L-I curve of the VCSEL. We show that, in these conditions, the system performance can be improved by transmitter predistortion. Enhancement of Chromatic Dispersion and Post-Filtering Effects Tolerances on Spectrum-Sliced WDM-PONs Using Self-Seeded Reflective-SOAs Duarte, Ulysses (University of Sao Paulo, Brazil); Rosolem, João (Fundação CPqD, Brazil); Penze, Rivael Strobel (Fundação CPqD, Brazil); Leonardi, Ariovaldo (CPqD, Brazil); Romero, Murilo A (University of Sao Paulo, Brazil) Abstract: A wavelength-reuse topology with downstream carriers based on 1.25 Gb/s directly modulated self-seeded reflective semiconductor optical amplifier (RSOA) is investigated in regard to post-filtering effects (PFE) and chromatic dispersion (CD) tolerances. Downstream and bidirectional reaches up to 80 and 60 km, respectively, with maximum 2 db power penalty (for a BER of 10-12) on 1.25 Gb/s are achieved for our combined scheme. The proposed topology enables the enhancement of CD and PFE tolerances as well as the best cost-effective configuration for intensityremodulation topologies while surpassing the conventional scheme pre-spectrum slicing light (PSSL) injection topology in 40 km. AGC EDFA Transient Supression Algorithm Assisted by Neural Network Carvalho, Heitor (CPqD, Brazil); G. Cassimiro, Israel J. (CPqD, Brazil); C. S. Filho, Francisco H. (CPqD, Brazil); Bordonalli, Aldário (Universidade Estadual de Campinas, Brazil); Oliveira, Juliano Rodrigues Fernandes de (CPqD Foundation, Brazil) Abstract: This work proposes an EDFA electronic automatic gain control (AGC) technique assisted by a cognitive neural network algorithm, providing gain control with transient suppression for any EDFA operation point in a DWDM dynamic optical network (input/output power condition). This electronic AGC consists of a proportional integral (PI) gain controller operating together with a neural network which estimates pump power to speed up the PI controller convergence. An experimental

8 demonstration of this algorithm is embedded in a System on Chip (SoC) inside an EDFA and operates under a reconfigurable DWDM optical network fully loaded (80x112 Gbits/s DP-QPSK channels), presenting overshoot/undershoot for AGC with transient suppression of approximately 0.8 and 3.1 db considering an add/drop of 7 from 8 and 79 form 80 channels (9 and 19 db input power variation). All-Optical Narrowband Spectral Slicing Encryption with Supergaussian Filter Martins, Claudinei (Pontificia Universidade Católica de Campinas, Brazil) Abstract: Recent literature points out the benefits of encrypting signals in the physical layer to improve network security. In particular, a novel all-optical encryption approach uses narrowband optical band-pass filters (OBPF) to split a dense wavelength division multiplexing (DWDM)-compatible signal into several spectral slices which, then, have their physical properties, such as phase and delay, altered; as a result, after multiplexing all slices, an encoded version of the input signal is obtained. The performance of such technique was previously evaluated by assuming that all OBPFs are characterized by ideal rectangular-shaped transfer functions. In this work, we investigate how such performance is affected by the utilization of practical OBPFs with supergaussian profiles. Simulation results indicate that there is a trade-off between the filter bandwidth and filter order that may allow for encrypted signals to be properly decoded even after propagation distances up to 400 km, which is typical metropolitan area network distance. 2h20-3h pm YELLOW AUDITORIUM - Communication Theory Hartley, Cosine and Sine Fractional Transforms over Finite Fields Lima, Paulo Hugo (Federal University of Pernambuco, Brazil); Campello de Souza, Ricardo (Federal University of Pernambuco, Brazil); Lima, Juliano (Federal University of Pernambuco, Brazil) Abstract: We introduce finite field versions of fractional Hartley, sine and cosine types 1 and 4 transforms using a matrix function approach. The proposed definitions employ a finite field extension of matrix functions, which does not require the construction of an eigenvector set of the corresponding transform. We also present a relationship between the Fourier and the Hartley fractional matrices and make a preliminary discussion concerning application scenarios for the developed theory. Interference analysis involving HEO satellites and fixed service receivers: probabilistic modeling of the fixed service receiving antenna elevation angle

9 Correa-Mena, Ana Gabriela (Universidad Tecnica Particular de Loja, Ecuador); Jose Mauro, Fortes (PUC, Brazil) Abstract: This paper focuses on the protection of terrestrial fixed service (FS) receivers from the aggregate interference produced by multiple highly elliptical orbit (HEO) systems operating in the 18 GHz band. Studies involving this type of interference usually consider the assumption that the victim FS receivers have their receiving antennas with zero degree elevation angle. In this work a probabilistic analysis, in which the elevation angle of the FS receiving antenna is modeled as a random variable, evaluates the aggregate interference produced by the satellites of multiple HEO systems into FS receivers. The proposed mathematical model is applied to two scenarios involving multiple interfering HEO systems and the obtained results are compared to those resulting from analyses that assume a zero degree elevation angle for the FS receiving antenna. 100Gbit/s FEC for OTN Protocol: Design Architecture and Implementation Results Salvador, Arley (CPqD, Brazil); Arantes, Dalton (State University of Campinas, Brazil); Oliveira, Julio Cesar (CPqD, Brazil); Mobilon, Eduardo (CPqD Telecom R&D Center, Brazil); Carvalho, Diego (State University of Campinas, Brazil); Nakandakare, Cleber (CPqD, Brazil) Abstract: Error correcting codes are widely used in telecommunication systems in order to increase the robustness of the system. With the exponential growth of the data communication world, the architecture of such systems have had to adapt to allow for improved channel capacity and reduced transmission costs. The architecture and hardware implementation challenges of the Reed Solomon RS(255, 239) for OTN networks in 100Gbit/s is presented. A New Map for Chaotic Communication Chaves, Daniel P B (UFPE, Brazil); Souza, Carlos Eduardo (Universidade Federal de Pernambuco, Brazil); Pimentel, Cecilio (UFPE, Brazil) Abstract: We propose in this paper a new one-dimensional chaotic map based on the hyperbolic tangent function that depends on a single control parameter r. The Lyapunov exponent of this map remains practically unaltered with the variation of r. Two new statistics are proposed to study the chaotic dynamic characteristics of chaotic maps, namely, the spread rate, and the contraction factor. The proposed map may be employed in chaotic communication systems based on symbolic dynamics with advantages over current approaches that uses piecewise linear maps. Successive Interference Cancellation Algorithm in m-qam Nonorthogonal Multicarrier Systems

10 Araújo, Daniel (Federal University of Ceará, Brazil); Lucena, Antônio Macílio (Natinal Institut of Space Research, Brazil); Mota, Joao Cesar Moura (UFC, Brazil) Abstract: This article investigates non-linear and linear receivers to detect N nonorthogonal m-qam signals through AWGN channel: maximum likelihood receiver (ML), minimum mean square error (MMSE), successive interference cancellation (SIC) and a completely new architecture called modified SIC. An analytical development of the project from each one of the proposed architecture is performed. As contribution we present the performance of the modified SIC in terms of bit error rate (BER) which is close to the performance of the ML receiver with less computational complexity. Another contribution is the determination of the minimum distance among nonorthogonal signals according to spectral overlapping considering $N=5$. Finally, the results are discussed as well as our future prospects of research. RED AUDITORIUM - Cognitive Radio Power-Rate Control with Directional Transmission and Reception in a Cognitive Radio Network Sanchez, Samuel (Central University of Las Villas, Cuba); Mafra, Samuel (UTFPR, Brazil); Fernandez, Evelio M.G. (Federal University of Parana, Brazil); Demo Souza, Richard (Federal University of Technology - Paraná (UTFPR), Brazil) Abstract: We study the benefits that antenna directivity and power control can bring to a cognitive radio ad hoc network, in terms of concurrent transmission probability, throughput and energy efficiency. The proposed strategies adequately adjust antenna beam pattern and the transmit power of the secondary users to increase the spectrum reuse while respecting a given constraint on the achievable primary rate. Two power control strategies are described: Rate-Efficient Power Control with Directional Transmission and Reception to maximize the secondary channel rate, and Energy- Efficient Power Control with Directional Transmission and Reception to maximize the energy efficiency of the secondary link. Numerical results show that the proposed schemes increase the concurrent transmission probability and that it is possible to increase the average rate and save energy with a lower cost than that of other proposals. Comparison Between Eigenvalue Fusion and Decision Fusion for Spectrum Sensing of OFDMA Signals Under Errors in the Control Channel Guimarães, Dayan A. (National Institute of Telecommunications - Inatel, Brazil); Costa, Lucas dos Santos (National Institute of Telecommunications, Brazil); de Souza, Rausley Adriano Amaral (National Institute of Telecommunications (INATEL), Brazil) Abstract: Recently, an eigenvalue fusion approach for detecting idle subchannels of OFDMA signals in the context of centralized cooperative spectrum sensing for

11 cognitive radio (CR) was proposed. Four detection techniques were analyzed, and it was concluded that the eigenvalue fusion outperforms the decision fusion scheme, in spite of the larger volume of data sent to the fusion center (FC) in the eigenvalue fusion. Nevertheless, it was conjectured that bit errors in the reporting channel could be more disastrous to the data representing CR decisions than to the data carrying eigenvalues, masking a potential advantage of the eigenvalue combining also in terms of the volume of data sent to the FC. In this paper we investigate this conjecture and conclude that it is partially true: CR decisions are indeed more sensitive to channel errors, but the amount of redundancy inserted to protect the decisions so as to equate the performances of the two fusion schemes does not always leads to a larger number of bits in the decision fusion. Then, one needs to trade performance and amount of data in the reporting channel to decide upon which fusion scheme must be adopted, in a case by case analysis. On the AUC Analysis in Cognitive Radio Networks over κ-µ Fading Channel with Noise Uncertainty von Glehn, Fabio (Universidade de Brasilia, Brazil); Dias, Ugo (University of Brasilia, Brazil) Abstract: In this paper, the perform analysis and the concepts of area under the ROC curve (AUC) in energy detection-based cognitive radio systems are presented and investigated. The small-scale variations of the fading signal under both light-of sight (LOS) and multipath scenarios, modeled by the κ-µ distribution, are considered with noise uncertainty. Moreover, admitting the presence of noise power estimation error as well as the usage of diversity schemes, the AUC are also outspread and studied. Finally, comparisons are performed and show an excellent improvement in the overall detection capability of the cognitive radio system, considering the effects of noise uncertainty when the most common diversity schemes are implemented. Spectral Efficiency and Aggregate Capacity in Cognitive Radio Networks- An Application Study Pimentel, Heloisa Peixoto de Barros (State University of Campinas - UNICAMP, Brazil); Cardieri, Paulo (University of Campinas, Brazil) Abstract: Cognitive radio could help to overcome the spectrum shortage by having an opportunistic system sharing a licensed spectrum with primary users. One of the main difficulties in the analysis of cognitive radio systems is to model the interference. Various works presented this modeling for two pairs of wireless users, one primary and one cognitive. Others consider two random overlaid networks. The approaches usually consider variations in densities, distances and power transmission (specially) of the

12 cognitive users. However, the alternatives to implement such systems can lead to some disadvantages inherent in the procedures adopted. This work presents an analysis of a scenario where a cognitive radio network shares the spectrum with a primary network, searching always to opportunities to take advantage of any possibility to increase its capacity. The network users (primary and cognitive) are distributed according to a Poisson Point Process (PPP), and use M-QAM modulation schemes. The cognitive network searches for opportunities that can be used for its transmission. This first approach considers a cognitive system that can work using different modulation schemes, increasing or decreasing its M-QAM modulation level according the better or the worse noise channel conditions respectively, according to the environment conditions and the traffic demand. Spectrum Sensing in Cognitive Radio Networks through Change Detection Technique Silva, Marcell (Universidade de Brasília, Brazil); Barreto, Andre N (University of Brasilia (UnB), Brazil) Abstract: Proper spectrum sensing is fundamental for the operation of cognitive radio networks, and must be performed reliably, i.e., with low false alarm and false detection rates, and as quickly as possible, which are usually conflicting requirements. In this contribution we propose the use of change detection techniques using adaptive RLS filters to detect spectrum occupancy, and show that this approach provides a faster and more efficient detection than the well known energy detection technique. GREEN ROOM Networking Life Cycle Cost Analysis of Substation Automation Implementation Farias, Vitor (Universidade Federal Fluminense, Brazil); Fernandes, Natalia Castro (Universidade Federal Fluminense, Brazil) Abstract: This paper proposes a quantitative evaluation of the classic discussion on cost-benefit and risk management involved in the implementation of telecommunications networks for Substation Automation Systems (SAS). The goal is to find the optimal point for investing in quality and reliability in order to maximize the profitability of the project. Various IEC61850 substation automation system (SAS) architectures are compared in terms of price, reliability, and their impacts in the power grid quality and cost of ownership of the project. The method used in this paper is the life cycle cost analysis (LCCA). It enables an objective decision of the topology design considering the high reliability requirements of SAS networks. This paper discusses how to make the best out of this new approach in protection and supervision of power systems.

13 Bufferbloat Systematic Analysis Cardozo, Thiago (LNCC, Brazil); da Silva, Ana Paula (Universidade Federal de Minas Gerais, Brazil); Vieira, Alex Borges (Universidade Federal de Juiz de Fora, Brazil); Ziviani, Artur (LNCC, Brazil) Abstract: There is a recent interest in the bufferbloat phenomenon as a possible explanation for the increased network latency observed in the Internet. The bufferbloat phenomenon is related to the excessive packet queuing in over-sized buffers inside the network that may lead to network performance degradation. In this context, we observe a lack of experimental results considering the practical aspects of off-the-shelf network devices. Therefore, in this paper, we present a systematic analysis of the bufferbloat phenomenon considering the microscopic view of the insides in the buffer architecture of typical network devices. Our experimental results show that bufferbloat might not be a significant problem in practice. First, the phenomenon is only observed in specific cases. Second, changes made to the queues under the control of the operating system have negligible effects. Finally, recent versions of the Linux kernel avoid bufferbloat, even in the specific cases in which it was observed. Effectiveness Analysis of Audio Watermark Tags for IPTV Second Screen Applications and Synchronization Calixto, Gustavo Moreira (University of Sao Paulo, Brazil); Angeluci, Alan (University of Sao Paulo, Brazil); Kurashima, Celso Setsuo (Federal University of ABC, Brazil); Lopes, Roseli (Polytechnical School of University of Sao Paulo, Brazil); Zuffo, Marcelo K (University of São Paulo, Brazil) Abstract: Recently, the industry and the research community have been exploring the use of more than one screen for the experience of interactivity with media content, primarily involving the TV. The techniques directly related with audio for second screen synchronization - the sound detection using the audio fingerprint technique - are well established. Experiments using audio watermark might reveal good solutions but are not fully explored in the literature. The aim of this paper is to evaluate and compare the transmission and receiving effectiveness of audio in the IPTV context. An analysis is carried out from laboratory trials using a second screen application with the function of detecting audio watermarks through different audio transmission and reception equipments. The results show that audio watermark can be transmitted over IPTV networks and also improve the interactive media usage scenarios. Evaluating multipath routing protocols to improve video transmission for precision agriculture

14 Sousa, Thiago M (University of Sao Paulo, Brazil); Margi, Cintia Borges (Universidade de São Paulo, Brazil); Silveira, Regina Melo (University of São Paulo, Brazil); Albertini, Bruno C (Universidade de São Paulo, Brazil); Saraiva, Antonio (Universidade de São Paulo, Brazil) Abstract: Precision agriculture (PA) is the application of technologies and principles to manage spatial and temporal variability related to crop production. A new PA application is emerging where semi-autonomous tractor systems with remote supervision requires real-time video transmission. This paper analyses the use of multipath routing protocols over an ad hoc network for farming areas and evaluates quality of service metrics, such as delivery frame rate, end-to-end delay and Peak- Signal-to-Noise Ratio, of the transmitted video flows. Results were obtained through simulation using NS-2 with Evalvid Framework. Simulation results show that QD-SMR has slightly higher PSNR results with less variability than AOMDV, and also better PSNR results than D-SMR and SMR when two or three video flows were transmitted. Using Asterisk as a Tool for Teaching Telephony Subject for Telecommunication Classes Dias, Michel (IFPB - Instituto Federal de Educação, Ciência e Tecnologia da Paraíba, Brazil); Gabi, Caio (Instituto Federal de Educação, Ciência e Tecnologia da Paraíba, Brazil); Rodrigues, Eloise (IFPB - Instituto Federal de Educação, Ciência e Tecnologia da Paraíba, Brazil); Morais, Diego (IFPB, Brazil); Perkusich, Angelo (Federal University of Campina Grande, Brazil) Abstract: This paper presents the use of Asterisk software for teaching telephony in Eletrical Engineering and Systems of Telecomunications undergraduate courses at the Federal Institute of Education,Science and Technology of Paraíba,João Pessoa,Paraíba, Brazil. To do this, and reproduce confidently a real world scenario the Asterisk software was choosen because its open source, flexible and free of charge to academic use. One complex scenario was proposed to the students developed in several steps, where in each one a problem was presented to them and asked to solve the end the whole scenario, everything was built by the students. The approach was validated during three academic semesters, during the years of 2012 and The empirical results shows an meaningfully improvement in the final general mean of the group s grades and reduction of the school dropout. 4h30-5h30 pm YELLOW AUDITORIUM - Signal Processing I

15 Channel Estimation Using Neural Network in Orthogonal Frequency Division Multiplexing-Interleave Division Multiple Access (OFDM-IDMA) System Taşpınar, Necmi (Erciyes University, Turkey) Abstract: In this paper, channel estimation based on neural network trained by Levenberg-Marquardt Algorithm is proposed to estimate the channel coefficients in Orthogonal Frequency Division Multiplexing-Interleave Division Multiple Access (OFDM-IDMA) systems. Conventional pilot based channel estimation algorithms like Minimum Mean Square Error (MMSE) and Least Squares (LS) are also utilized to make comparison with our proposed method with the help of bit error rate (BER) and mean square error (MSE) graphs. In this study, it is demonstrated with the computer simulations that, channel estimation based on neural network ensures better performance than LS algorithm without the requirement of channel statistics and noise information which MMSE algorithm needs to estimate the channel coefficients. Even though MMSE algorithm still shows the best performance in channel estimation, our proposed method has the advantage of being less complex and easy to apply.because of being multiuser system, the performance of OFDM-IDMA is also evaluated for different user numbers under the channel estimation employing LS, MMSE and neural network methods, respectively. It is shown that the system performance decreases as long as the number of user is increased. Enhancing DSSS-Signals Channel Estimation Through Compressive Sensing Chinatto, Adilson W (Universidade de Campinas, Brazil); Junqueira, Cynthia (Institute of Aeronautics And Space, Brazil); Romano, João (State University of Campinas, Brazil) Abstract: A new approach for channel estimation, based on the concept of compressive sensing is presented for situations where signals are DSSS transmitted. Compressive sensing encompasses elegant mathematical background where the information of the sparse characteristic of the signal is used to create an efficient representation of it using fewer measurements than required by the Shannon-Nyquist criterion. The reconstruction is performed through linear programming or greedy algorithms. In this paper, we demonstrate that compressive sensing can enable reduction in the analog-to-digital sampling rate, allowing the design of simpler and cheaper receivers, while keeping or improving resolution in the DSSS channel estimation. New Interpolator and Data Detector for Full Digital BPSK Demodulator Figueredo, Caio (Universidade Federal do Ceará, Brazil); Lucena, Antônio Macílio (Natinal Institut of Space Research, Brazil); Mota, Joao Cesar Moura (UFC, Brazil)

16 Abstract: This work presents a new structure for an all-digital BPSK demodulator developed for space communications that performs simultaneously the sampling and down convertion from intermediate frequency signal to the baseband signal. A new interpolator is proposed in order to simplify the demodulator implementation. Such interpolator generates a correlation between the samples and it was necessary to design a new ML data detector to process the samples corrupted by gaussian and colored noise. The effects of the new interpolation at the noise are analyzed as well as the way it affects the whole demodulator performance. Simulations were performed and the results are presented to confirm theoretical analysis. RED AUDITORIUM - Cellular Networks I Spectral and Energy Efficiency with Satisfaction Constraints Maurício, Weskley (Federal University of Ceará, Brazil); Lima, Francisco Rafael Marques (Wireless Telecom Research Group (GTEL), Brazil); Maciel, Tarcisio F. (Federal University of Ceará, Brazil); Cavalcanti, Francisco R. P. (Federal University of Ceará, Brazil) Abstract: In this article we revisit the Radio Resource Allocation (RRA) problem of maximizing the total transmit data rate subject to satisfaction guarantees. It was previously studied on the perspective of Resource Block (RB) assignment (only) considering Equal Power Allocation (EPA) and, herein, we study this problem assuming adaptive power allocation. Two power allocation strategies are proposed and shown to be able to achieve energy and/or spectral efficiency gains compared to the original solution proposed in the literature. While the first power allocation strategy is capable of saving a considerable amount of transmit power maintaining the same transmit data rate of EPA, thus obtaining energy efficiency gains, the second strategy is able to convert this energy efficiency gain in spectral efficiency. A Priori Selection of High Accuracy Mobile Station Position Estimates Campos, Rafael S. (UFRJ - Universidade Federal do Rio de Janeiro, Brazil); Lovisolo, Lisandro (Universidade do Estado do Rio de Janeiro, Brazil) Abstract: A priori identification and selection of high accuracy position estimates, i.e., with error below 100 meters, is particularly relevant for critical location-based applications, like vehicle tracking and, specially, emergency call positioning. This work presents a backpropagation artificial neural network classifier used to predict the accuracy of mobile station position estimates produced by a network-based radiofrequency fingerprinting method, RF-FING+RTD-PRED (Predicted Radio-frequency Fingerprint with Round Trip Delay), previously formulated by the authors. The classifier employs the same radio-frequency parameters used by the aforementioned method

17 plus some additional network data. In field tests carried out in GSM (Global System for Mobile Communications) networks in urban and suburban areas, where 6600 measurement reports have been collected, a 89% precision in the identification of high accuracy position estimates has been achieved. The presented method is promptly extensible to 3G cellular networks. Efficient Frequency Domain Zadoff-Chu Generator with Application to LTE and LTE-A Systems de Figueiredo, Felipe Augusto (CPqD, Brazil); Mathilde, Fabiano (CPqD - Center of Research and Development in Telecommunications, Brazil); Cardoso, Fabbryccio A. (CPqD, Brazil); Vilela, Rafael (CPqD, Brazil); Miranda, João Paulo (CPqD, Brazil) Abstract: This paper presents a configurable and optimized hardware architecture for computing Zadoff-Chu (ZC) complex sequences in the frequency domain. It is a hardware-efficient and accurate architecture for computing ZC sequences in realtime. The architecture is mainly based on the CORDIC algorithm for computing complex exponentials using only shift and add operations. Due to transformations applied to the Zadoff-Chu equation it is possible to eliminate the use of multipliers with nonconstant terms. This hardware architecture is employed by the PRACH module during the reception and detection of random access preambles. Its main advantage is that it eliminates the need for storing a large number of long complex ZC sequences. GREEN ROOM - Information Theory and Coding I Coded Cooperation with Single Parity-Check Turbo-Product Codes over Fast Fading Channels Guimarães, Dayan A. (National Institute of Telecommunications - Inatel, Brazil); Gomes, Geraldo (INATEL, Brazil); Barbosa, Guilherme Varela (National Institute of Telecommunications - Inatel, Brazil); Uchôa-Filho, Bartolomeu F. (Federal University of Santa Catarina, Brazil) Abstract: This paper describes a new coded cooperation scheme based on single parity-check turbo-product codes. The channel soft-information from the source and the relays are also combined in a novel way at the destination. The scheme has simple encoding and decoding, and unveils potential for large cooperation gains in fast fading channels. Design of Lattice Network Codes Based on Construction D Branco da Silva, Paulo (Federal University of Santa Catarina, Brazil); Silva, Danilo (Federal University of Santa Catarina, Brazil)

18 Abstract: Physical-layer network coding takes advantage of signal interference to transmit linearly combined data from multiple nodes. Nazer and Gastpar introduced the use of nested lattice codes to network coding by demonstrating that linear combination according to channel dependent integer coefficients provides an effective coding scheme. Feng et \textit{al.} presented an algebraic approach for this strategy based on modules. They developed practical design guidelines, specially for Construction A. This paper intends to show the same possibilities for lattices built with the multilevel Construction D. We know from Feng et \textit{al.} that Construction D achieves higher coding gains than A, and we also know that multilevel codes can form large modulations from simple level codes. We present a multi-stage decoder with a modified Viterbi metric for lattice decoding. Simulation results verify the scheme's efficiency for a $64$-QAM with effective rate of $5$ bits per complex dimension (b/cdim) and for a $16$-QAM with effective rate of $3$ b/cdim. Capacity of Symmetric Finite Input and Continuous Output Channels Arpasi, Jorge P (University of Pampa - UNIPAMPA, Brazil) Abstract: In this work we study channels with finite input alphabet and continuous output alphabet and we give step-by-step proofs ow two results: 1.-The capacity of the channel can be computed by finding a random variable over the inputs in such a way that the Kullback-Leibler distance D(p(y x_i) p(y)) is constant for any x_i of the input alphabet. 2.-The capacity of the symmetric channel can be computed by making the random variable over the inputs be uniform, i.e., probability p(x_i) constant for any input x_i.

19 August, 19th - Tuesday 2h - 3h pm YELLOW AUDITORIUM - Signal Processing II Snapping Shrimp Noise Reduction using Convex Optimization for Underwater Acoustic Communication in Warm Shallow Water Guimarães, Dayan A. (National Institute of Telecommunications - Inatel, Brazil); Chaves, Lucas Silvestre (National Institute of Telecommunications - Inatel, Brazil); de Souza, Rausley Adriano Amaral (National Institute of Telecommunications (INATEL), Brazil) Abstract: We propose an ambient noise reduction technique for underwater acoustic communication systems in warm shallow water, where the snapping shrimp impulsive noise is a common impairment. The denoised signal is the solution of an unconstrained scalarized bi-criterion convex optimization problem. One of the criterions is based on the robust least-squares signal reconstruction approach, for which the sum of the Huber penalty function of the residuals is minimized. The other criterion uses a quadratic smoothing regularization term, acting on the first difference of the denoised signal samples. It is shown that the proposed technique can significantly reduce the ambient noise and, thus, reduce the bit error rate of an underwater digital communication system A Comparative Study of Non-MSE Criteria in Nonlinear Equalization Boccato, Levy (University of Campinas, Brazil); Silva, Daniel (University of Campinas, Brazil); Fantinato, Denis (University of Campinas, Brazil); Ferrari, Rafael (University of Campinas (UNICAMP), Brazil); Attux, Romis Ribeiro (State University of Campinas - Unicamp, Brazil) Abstract: This work studies the application of non-mse criteria to adapt the linear readout of Extreme Learning Machines (ELMs) in the context of communication channel equalization. A qualitative and experimental analysis is performed, in terms of bit error rate, optimization surface and decision boundary. The results reached by the ELM-based equalizer, considering three different noise models, did not reveal clear advantages of using criteria based on the concepts of error entropy, correntropy, and the L1-norm of the error. Notwithstanding, the observed results motivate a theoretical investigation on the conditions under which the potential discrepancies between the optimal solutions of these criteria may be stressed.

20 A Volterra Filtering Approach for the Polynomial Formulation of the Constant Modulus Criterion Fantinato, Denis (University of Campinas, Brazil); Attux, Romis Ribeiro (State University of Campinas - Unicamp, Brazil); Suyama, Ricardo (Universidade Federal do ABC, Brazil); Neves, Aline (Federal University of ABC, Brazil); Romano, João (State University of Campinas, Brazil) Abstract: In this work, an extended polynomial formulation of the constant modulus (CM) criterion under quadratic constraints is presented. Based on the method of Lagrange Multipliers, this `Volterra-CM formulation' brings very relevant information about the structure of the null-gradient CM solutions in the equalizer parameter space, including a conjecture regarding the relationship between the smallest multiplier and the optimal CM receiver. In the case of a two-tap filter, the proposed formulation allows that the solutions be obtained in terms of a single parameter, the corresponding Lagrange multiplier. For filters with more than two taps, the problem requires that a nonlinear system be solved, which is done with the aid of an iterative algorithm. The obtained global convergence rates show that the formulation is an effective tool to describe the structure of the optimal CM solution. RED AUDITORIUM - Celular Networks II A Genetic Algorithm Based Approach for Resource Allocation in LTE Uplink da Mata, Saulo Henrique (Federal University of Uberlândia, Brazil); Guardieiro, Paulo R. (Federal University of Uberlandia, Brazil) Abstract: LTE has become the de facto technology for the 4G networks. It offers unprecedented data transmission and low latency for several types of applications and services. In this paper, we investigate the resource allocation in the LTE uplink, which is widely known as a complex optimization problem. To solve this issue, we present a new scheduling algorithm based on Genetic Algorithms (GA). The proposed algorithm is evaluated using the Network Simulation 3 in scenarios of video transmission with focus on video chatting. The performance of the GA based algorithm is compared with the main algorithms present in the literature. Simulation results show the superiority of the GA based approach to offer better video quality. Particle Swarm Optimization for Base Station Placement

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