Turbo-per-Tone Equalization for ADSL Systems

• Main Authors: Vanhaute Hilde, Moonen Marc
• Format: Article
• Language: English
• Published: SpringerOpen 2005-01-01
• Series: EURASIP Journal on Advances in Signal Processing
• Subjects: ADSL; multicarrier modulation; turbo equalization
• Online Access: http://dx.doi.org/10.1155/ASP.2005.852

<p/> <p>We study the equalization procedure in discrete multitone (DMT)-based systems, in particular, in DMT-based ADSL systems. Traditionally, equalization is performed in the time domain by means of a channel shortening filter. Shifting the equalization operations to the frequency domain, as is done in per-tone equalization, increases the achieved bitrate by 5&#8211;10%. We show that the application of the turbo principle to per-tone equalization can provide significant additional gains. In the proposed receiver structure, referred to as a "turbo-per-tone equalization" structure, equalization and decoding are performed in an iterative fashion. Equalization is done by means of a linear minimum mean squared error (MMSE) equalizer, using <it>a priori</it> information. We give a description of an efficient implementation of such an equalizer in the per-tone structure. Simulations show that we obtain a bitrate increase of 12&#8211;16% compared to the original per-tone equalization-based receiver structure.</p>