Crosstalk mitigation in DMT VDSL with impulse noise

Crosstalk and impulse noise are two principal sources of degradation in very-high-rate digital subscriber line (VDSL) transmission systems. The traditional single-user data detector for such systems merges crosstalk into the background noise, which is assumed to be white and Gaussian. Recent research has explored the nature of crosstalk signals and shown the potential benefits of multiuser detection (MUD) for VDSL signals with strong crosstalkers. Impulse noise is one of the most difficult transmission impairments to suppress, and is poorly characterized and understood as well. In DSL transmission, impulse noise is typically combated with interleaved forward-error correction (FEC). However, recent data indicate that a significant minority of impulse-noise events are longer than the maximum error-correcting capacities of the default interleaved FEC provided within current ANSI standards. Thus, it is of interest to consider signal processing methods that can jointly mitigate crosstalk and impulse noise. In this paper, we explore such a technique based on a recently developed robust M-detector structure for MUD in non-Gaussian ambient noise.