Optimal Threshold Calculation for Improved Impulsive Noise Mitigation in the Frequency Domain

Impulsive noise (IN) can significantly degrade the performance of multi-carrier based communication systems. In order to improve the performance of such systems, conventional IN suppression methods have been proposed to process the signal in the time domain. However, attention has recently focused on using methods implemented in the Frequency Domain (FD). In general, the aim of IN frequency domain estimation schemes is to consider noise samples whose amplitudes are below a fixed threshold as Gaussian distributed noise and therefore are blanked (nulled). In contrast to existing work, this paper presents a novel optimal threshold calculation method to improve the IN frequency domain mitigation methods. The system adopt in this paper is the G.fast standard which uses high order QAM constellations over copper channels. The derived optimum threshold is used in an IN compensation method based on the relationship between two parameters, namely, impulsive Index A and the noise ratio Γ. In order to validate the effectiveness of the proposed scheme, its performance is compared with that of the conventional FD mitigation method which uses a fixed threshold. The impact of both the impulsive Index A and the noise ratio Γ on the DMT-based G.fast copper channel is also discussed in detail. Results show that the proposed method considerably outperforms conventional frequency domain IN mitigation schemes.