Performance analysis of adaptive hybrid nonlinear preprocessors for impulsive noise mitigation over power-line channels

Impulsive noise (IN) over power-lines can significantly corrupt communication signals. To diminish its effect, a nonlinear preprocessor is usually applied at the receiver's frond-end to blank or clip the incoming signal when it exceeds a certain threshold. Applying a combination of blanking and clipping in a hybrid fashion is characterized by two thresholds T₁ and T₂ (T₂ = αT₁), where α is a scaling factor. Previous studies assumed a fixed value for the scaling factor and found that optimizing the threshold T₁ is the key to improve performance. In contrast to the existing work, in this paper we show that the performance of the hybrid technique is sensitive not only to the threshold but also to the scaling factor, and in light of this we propose to enhance the capability of this technique by optimizing the two parameters. System Performance is evaluated mathematically in terms of the probability of missed blanking/clipping (P_m), probability of IN identification (P_i) and the symbol error rate (SER) performance. In all our investigations, simulation results are provided to validate the analysis. Results reveal that the proposed scheme is superior in terms of minimizing P_m and maximizing P_i which consequently results in improving SER performance.