Filtros digitais para a separação de subbandas em sistemas PLC baseados em clustered-OFDM

Abstract

This work investigates the use of finite impulse response (FIR) and infinite impulse response (IIR) digital filters to separate the signals belonging distinct clusters in a clustered orthogonal frequency division multiplexing (clustered-OFDM) scheme, when it is applied to power line communication (PLC) system. In this context, we introduce a formulation to take into account the choice of the digital filter for the clustered-OFDM scheme. Based on this formulation, an equation that quantifies the data-rate as a function ofmultichannel signal noise ratio, digital filter design specification and length of the digital filter is presented. Performance analyses based on a previously selected set of digital filters over three scenarios, channel corrupted by additivewhite Gaussian noise (AWGN), indoor PLC channel corrupted by the noise (measured in a residence located in Juiz de Fora city, MG) and outdoor PLC corrupted by the noise (measured in a low voltage distribution network in Juiz de Fora city, MG), are presented. According to numerical results, Chebychev type II, interpolated FIR (IFIR) and equiripple minimum phase FIR digital filters offers the best benefits in terms of less data-rate loss and computer complexity reduction. Considering the influence of the finite precision in these three digital filters, simulation results shows that the quantized Chebychev type II IIR digital filter attains the smallest data-rate loss and, as a consequence, it a very appropriate digital filter for clustered-OFDM schemes.