The Impact of Statistical Noise Modeling on the Error-Rate Performance of OFDM Power-Line Communications

In this paper, the impact of statistical noise modelling on the error performance achieved by orthogonal frequency-division multiplexing (OFDM) over indoor broadband power-line channels is investigated. Different classes of statistical models suitable to represent power-line noise are illustrated and their impact on the error performance of a specific OFDM system is assessed via computer simulations. Numerical results are compared with the error performance provided by the same system in the presence of measured power-line noise; this is evidence that a realistic indication of error performance can be achieved only if the power spectral density of the adopted noise model exhibits a good match with that of the measured noise. In practice, this result can be achieved by modeling the power-line noise as a moving average random process of proper order; however, a satisfying match can be achieved as well if other simple noise models available in the technical literature are adopted

Design and Implementation of a Wideband Channel Sounder for Low-Voltage Powerlines

Estimating the input-output behavior of low voltage powerline channels for indoor high speed data communications requires the availability of proper wideband channel sounding tools. In fact, the properties of real world powerline channels are substantially different from those commonly exhibited by their wireless counterparts, so that standard methods for wireless channel sounding cannot be adapted to a powerline scenario. In this paper, after providing some general design guidelines for powerline channel sounding, a detailed description of a FPGA-based implementation of a wideband powerline channel sounder is provided. Such a tool is based on low cost hardware and is flexible, since it can be easily customized to user needs using a set of simple graphical user interfaces. Some of its specific applications, namely the estimation of the time-varying transfer function of an indoor powerline channel and the evaluation of the power spectral density of the noise affecting it, are illustrated to show the potentialities of the developed equipment

A novel bit and power loading algorithm for narrowband indoor powerline communications

The problem of bit and power loading for bit rate maximization in OFDM data communications over indoor powerline channels is investigated and a simple method for bit/power allocation in a single cycle of the mains is developed. The proposed solution is based on the so called Zadeh's representation for modelling the linear periodically time-varying behavior of powerline channels. Numerical results show the superiority of the proposed method over other solutions available in the technical literature in a real world scenario

Equalization of Narrowband Indoor Powerline Channels for High Data Rate OFDM Communications

In this paper the well known Zadeh’s series representation of a linear periodically time varying system is exploited to develop linear equalization techniques for narrowband powerline communications based on orthogonal frequency division multiplexing. Numerical and experimental results referring to the band 200-500 kHz evidence that a coherent receiver exploiting the proposed equalizers can significantly outperform both its counterpart based on conventional channel estimation/ equalization techniques and differential detection with a limited complexity. This leads to the conclusion that a coherent receiver incorporating the proposed equalization techniques represents a technically appealing solution for narrowband high data rate powerline communications in indoor scenarios

Broadband system models based on Zadeh's representation for indoor powerline channels: An experimental validation

The discrete-time representation of a broadband powerline channel as a linear periodically time variant system poses serious problems in terms of computational complexity. In this paper we exploit the principles of the Zadeh's series expansion to devise a new discrete-time system model, characterized by a limited computational complexity and particularly suitable for an implementation on embedded programmable hardware. Then, we illustrate simple methods for estimating the parameters of the proposed model and apply them to the development of a broadband channel sounding tool for powerlines. Our experimental and numerical results show that the proposed model is able to provide a faithful representation of the periodically time varying behavior of indoor powerline channels

On the Use of Zadeh's Series Expansion for Modeling and Estimation of Indoor Powerline Channels

Indoor powerline channels usually exhibit a cyclic input–output behavior due to the time-varying impedance of power loads. This makes typical time-invariant system models unsuitable to provide a faithful representation of such channels. In this paper, starting from the so-called Zadeh's series expansion, a discrete-time parametric representation of a linear periodically time-varying system is developed, and it is shown how a reduced-complexity version of it can be adopted to model indoor powerline channels. Then, various methods for estimating the parameters of the proposed representation are developed and compared in terms of performance and complexity. Numerical results evidence that our reduced complexity model is able to provide an accurate representation of indoor powerline channels and is of practical interest for both smart-grid applications and home area networks

Statistical Modeling of Periodic Impulsive Noise in Indoor Power-Line Channels

In this paper, novel statistical models for the representation of the periodic impulsive noise generated by power loads connected to power grids in indoor scenarios are developed. Their derivation is based on a set of experimental results acquired in a measurement campaign and on deseasonalized autoregressive moving average modeling of cyclostationary random processes. Numerical results are evidence that the proposed models can provide an accurate stochastic representation of the periodic impulsive noise generated by specific appliances in the 1\u201330 MHz band, at the price of limited computational complexity