Digital interference cancellation for DSL using information from the RS decoder

Abstract

AbstractOne of the factors that affect the performance of Digital Subscriber Loop (DSL) systems is non‐stationary interference, comprising of impulse noise and Radio Frequency Ingress (RFI). In order to achieve reliable transmission, DSL transceivers employ a Forward Error‐Correction scheme that consists of interleaving and Reed–Solomon (RS) encoding. Although RFI typically affects a small area of a symbol in DMT‐based DSL systems, its duration is much longer than that of impulse noise and many DMT symbols are impacted. This leads to increased interleaving and/or RS parity requirements. This paper presents a digital RFI cancellation algorithm for DMT‐based DSL systems. The method exploits information contained in the output of the RS decoder. Under certain conditions it can remove part of the effect of RFI on the received symbols and lead to reduction of the interleaving delay or the RS code parity. The technique does not require any changes at the transmitter and can therefore be incorporated in current DMT‐DSL systems. Copyright © 2007 John Wiley & Sons, Ltd.