Showing papers by "Moises V. Ribeiro published in 2017"

Coupling for Power Line Communications: A Survey

Abstract: The advent of power line communication (PLC) for smart grids, vehicular communications, and data network access, has recently gained ample interest among the researchers and industries. Couplers - devices used to inject data communication signals into (Alternating Current or Direct Current) power lines are very important components of a PLC system. There is, however, an obvious gap in literature for a detailed review of existing PLC couplers. In this paper, we present a comprehensive review of couplers, which are required in narrowband and broadband PLC transceivers. We provide, also, a novel classification of PLC couplers based on the type of physical coupling, voltage levels, frequency bandwidth, propagation mode, and number of connections. Prevailing issues that protract the design of couplers and consequently subtended the invention of different types of couplers are clearly described. This survey will guide researchers, and designers alike, into a quicker resourcing when studying coupling in narrowband and broadband PLC systems.

A Spectral Compressive Resource Allocation Technique for PLC Systems

Abstract: This paper focuses on the benefits of the existing relationship among consecutive subchannels (spectral information) in a multi-carrier modulation-based power line communication system for reducing the computational complexity and signaling overhead associated with resource allocation techniques. In this regard, we introduce the spectral compressive resource allocation technique, which reduces the computational complexity and the signaling overhead by grouping subcarriers into chunks, whose length/bandwidth is defined with basis on the so-called normalized signal to noise ratio coherence bandwidth. Moreover, we address the combination of the proposal with another technique that exploits the existing temporal relationship within periodically time-varying power line channels. Based on a data set composed of in-home power line channel estimates and additive noise measurements, we quantify the tradeoff between computational complexity reduction and data rate degradation under distinct scenarios and conditions, and indicate circumstances in which the proposed technique is more useful. Finally, we show that the exploitation of both temporal and spectral information altogether results in more computational complexity reduction and/or less data rate degradation in comparison to other techniques.

A temporal compressive resource allocation technique for complexity reduction in PLC transceivers

Abstract: This work introduces a novel resource allocation technique for dealing with linear and periodically time-varying power line channels when an orthogonal frequency division multiplexing scheme is applied. By exploiting the correlations within one cycle of the mains signal, among cycles of mains signal and a combination of these connections, the proposed technique can offer three distinct trade-offs between computational complexity reduction and data-rate loss. Numerical results, which are based on measured data, are used to analyse these trade-offs, when these inter-cycle and intra-cycle relationship are taken into account. Also, we verify that the use of the normalised signal-to-noise ratio incurs very low performance degradation, and because of computational complexity rationale, its use is strongly recommended. Additionally, we show that those cases, in which the correlations among the cycles of the mains signal is relevant, offer the best trade-off between computational complexity reduction and data-rate loss. Finally, we show that the proposed technique can achieve the optimal data-rate and offers substantial improvements in terms of computational complexity when compared with existing approaches, including the Institute of Electrical and Electronics Engineers 1901 standard. Copyright © 2015 John Wiley & Sons, Ltd.

Set-Membership Type-1 Fuzzy Logic System Applied to Fault Classification in a Switch Machine

Abstract: This paper focuses on the classification of faults in an electromechanical switch machine, which is an equipment used for handling railroad switches. In this paper, we introduce the use of Set-Membership concept, derived from the adaptive filter theory, into the training procedure of type-1 and singleton/non-singleton fuzzy logic systems, in order to reduce computational complexity and to increase convergence speed. We also present different criteria for using along with Set-Membership. Furthermore, we discuss the usefulness of delta rule delta, local Lipschitz estimation, variable step size, and variable step size adaptive techniques to yield additional improvement in terms of computational complexity reduction and convergence speed. Based on data set provided by a Brazilian railway company, which covers the four possible faults in a switch machine, we present performance analysis in terms of classification ratio, convergence speed, and computational complexity reduction. The reported results show that the proposed models result in improved convergence speed, slightly higher classification ratio, and remarkable computation complexity reduction when we limit the number of epochs for training, which may be required due to real-time constraint or low computational resource availability.

Statistical analysis and modeling of a novel parameter for resource allocation in multicarrier PLC systems

Abstract: This work outlines a novel parameter that is capable of characterizing the flatness of the normalized signal-to-noise ratio for resource allocation purposes in power line communication (PLC) systems, which are based on multicarrier modulation schemes This parameter, named normalized signal-to-noise ratio coherence bandwidth, can be used for grouping adjacent subchannels therefore reducing the computational complexity of resource allocation techniques Additionally, we discuss a comparative analysis between the proposed parameter and the coherence bandwidth for resource allocation purposes, which leads us to conclude that the former is more appropriate than the latter for PLC systems Moreover, we show a statistical analysis of the proposed parameter and model it with different distributions based on noise measurements and channel estimates of broadband in-home, outdoor, and hybrid PLC-wireless environments On the basis of data sets obtained from measurement campaigns covering the frequency bands of 17 to 30, 17 to 50, and 17 to 100 MHz, we show that the best distributions for modeling the proposed parameter are inverse Gaussian, Nakagami, gamma, and Gaussian mixture, depending on the type of the channel (in home, outdoor, and hybrid PLC wireless) and the frequency band

Computing derivatives in interval type-2 fuzzy logic systems trained by steepest descent method for fault classification in a switch machine

Abstract: A switch machine is an electromechanical device that allows railway trains to be guided from one track to another. Among all possible faults that can occur in a switch machine, the three mains ones are: lack of lubrication, lack of adjustment and malfunction of a component. Aiming to classify these faults, an important contribution of this work is to address the height type-reduction and interval singleton type-2 fuzzy logic system derivatives. The computational simulations are performed with real data set provided by a Brazilian company of the railway sector. The obtained results are compared with other models reported in the literature (Bayes theory, multilayer perceptron neural network and type-1 fuzzy logic system), demonstrating the effectiveness of the proposed classifier and revealing that the proposal is able to properly handle with uncertainties associated with the measurements and with the data that are used to tune the parameters of the model. In addition, the convergence speed and performance analysis show that the proposed interval singleton type-2 fuzzy logic system is attractive for classifying faults in a switch machine.

A Novel Synchronization Scheme for Impulsive UWB-based PLC Systems

Abstract: This paper focuses on a low-cost synchronization technique based on power criteria for impulsive ultra wideband scheme applied to power line communication systems. The advantage offered by this technique is that the knowledge of both channel pulse response and noise information are not required. To assess the proposed technique, we discuss performance results obtained with typical in-home, outdoor, and low-voltage power line channels covering the frequency band between 1.7 and 50 MHz and additive noises modeled as white Gaussian and impulsive Gaussian. The results show that the proposed technique achieves the best performance in terms of detection probability, false alarm probability, and bit error rate in comparison with previous synchronization techniques, which were design to work with the aforementioned data communication system. Besides, implementation analysis on field programmable gate array shows that the proposed technique demands less hardware resource utilization than previous techniques and its finite word length implementation with at least 16 bits word length results in negligible performance degradation.