Adaptive Noise Mitigation in Impulsive Environment: Application to Power-Line Communications

In this paper, we address the general issue of asynchronous impulsive noise mitigation and its application over coded power-line communications ( PLC). As is well known, PLC channels usually suffer from significant degradation due to impulsive interference generated by electrical appliances. The use of a level limiter is a simple and intuitive technique, widely used to mitigate the noxious effect of impulsive noise in these channels. However, the determination of the clipping threshold remains, most of the time, empirical, and the impulse statistics are usually assumed to be known. In a previous study, we proposed an original threshold determination based on signal detection theory, using the well-known false alarm and good detection tradeoff. Here, we further investigate the proposed optimization method in closed form. We compare two tradeoff criteria by means of a receiver operating curves analysis. We clearly show that the resulting decision fits well with encountered bit-error rate performances. We also evaluate the influence of impulsive noise statistics estimation on the performance of the proposed approach. To do so, we assess the robustness of the classical method of moments on Gaussian mixture estimation. It clearly appears that the estimation method is reliable for reasonable values of the impulse occurrence. As one of the main results of this paper, we make a proposal for impulse statistics estimation under "severe" conditions (i.e., for very rare impulse events, based on impulse detection over corrupted OFDM symbols). Subsequently, we propose a general scheme of automatic impulse mitigation, according to the disturbance ratio of the environment. Finally, the performance of the approach is evaluated over the Home-Plug AV (HPAV) physical layer.