Linear IIR Precoding for Non-Redundant Transmission over Minimum-Phase Channels in Wireline Multitone Systems

Discrete multitone (DMT) systems need the use of a guard interval, known as cyclic prefix (CP), to avoid intersymbol interference (ISI) and interchannel interference (ICI). Unfortunately, this prefix produces a decrease in the achievable bandwidth efficiency. To overcome this problem, we present in this paper an IIR linear precoder that adds memory in the time-domain, avoiding the need of a guard time. It is shown that the received signal with this precoder and the received signal in a DMT system that uses CP are identical, so perfect reconstruction is possible in a noise-free situation. In addition, the behavior of this scheme in presence of noise is the same as in a DMT system with CP, allowing the use of bit and power loading algorithms. It is also proved that the only condition for the precoder stability is that the channel is minimum-phase. As an example, it is shown the good performance of this algorithm in an ADSL environment.