Vectored-DMT: a FEXT canceling modulation scheme for coordinating users

This paper describes a modulation scheme achieving far-end crosstalk (FEXT) cancellation, assuming that joint signal processing among the users can be performed at either the receiver or at the transmitter side. The multi-user channel is modeled as a multiple-input-multiple-output (MIMO) system, and the development starts with the zero-forcing generalized decision feedback equalizer (GDFE). Structures are derived, which combine the discrete multi-tone (DMT) transmission technique with either successive cancellation at the receiver or precoding at the transmitter. A promising application of the proposed scheme is in FEXT-limited digital subscriber line (DSL) systems. Computer simulations demonstrate that significant performance improvements can be realized in such scenarios.