Simple reception techniques for coordinated two-pair digital transmission

Abstract

Simple coordinated transmission schemes are proposed and analyzed, in which independent but identically PAM (pulse-amplitude-modulation) coded data are transmitted over two subscriber loop pairs in the presence of near-end crosstalk from other pairs' transmitters. A maximum-likelihood detection scheme utilizing noise variance and correlation between the two pairs is shown to yield significant improvement in performance, especially if there is an unbalance in the channel signal-to-noise ratios on the two pairs, or if there is significant noise correlation.<>