A review of crosstalk estimation methods using SNR feedback

At short distances, data rates of digital subscriber line (DSL) systems are typically limited by crosstalk between adjacent lines rather than by background noise. In the downstream, from the access node to the customer premises equipment (CPE), precoding can reduce crosstalk significantly if accurate estimates of crosstalk channel coefficients are known. This paper analyzes this SNR-based estimator and obtains conditions under which successive iterations of the estimator are guaranteed to converge to the true crosstalk coefficients.