Application of wavelet for improvement of rate-reach performance in ADSL interference environment

This paper discusses the cancellation of near end crosstalk (NEXT) and far end crosstalk (FEXT) using a non-parametric wavelet denoising technique. Crosstalk noise is estimated using heuristic Steinpsilas unbiased risk estimate (SURE) and Bayesian risk minimization threshold function. The noise level estimated by a threshold function is used by thresholding rules to mitigate the effect of noise in the signal. A comparison of rates achieved with three thresholding techniques viz; soft thresholds, hard thresholds and a garrote threshold have been presented. Results obtained with AWGN, 24 ADSL NEXT and 24 ADSL FEXT disturbers show a significant improvement in rate reach performance upwards of 4 Mbps. The computational complexity in the wavelet denoising technique is independent of the number of crosstalk sources and hence can be suitable candidate for a practical deployment of mitigation of cross talk.