Mitigation of radio interference in xDSL transmission

The twisted pair copper access network was originally intended as a transmission medium for low-bandwidth analog voice signals. Unlike voiceband modems that operate in this frequency band, emerging high-speed digital transmission systems like ADSL and VDSL use a much larger spectrum. Because VDSL signals contain frequencies up to several megahertz, these broadband signals are susceptible to more hostile noise conditions. This article identifies the different noise impairments and shows how their effect can be mitigated in multicarrier-based VDSL systems.