Time-Domain MIMO Precoding for FEXT Cancellation in DSL Systems

We study the application of multiuser MIMO precoding for the cancellation of far-end crosstalk (FEXT) in DSL systems. We present a novel approach where the FEXT is canceled in the time-domain which offers some significant advantages over the common frequency-domain cancellation techniques. The time-domain adaptive filters used to compensate for the FEXT on the the time-domain transmit signal are obtained by an SNR-based system identification. We analyze the influence of several parameters on the identification of the FEXT transfer functions. Finally, we show that the proposed method with timedomain FEXT cancellation improves the signal-to-noise ratios of the individual subscribers and thus increases their data rates compared to uncompensated transmission.