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  • Research Article
  • Open Access

Zero-Forcing Frequency-Domain Equalization for Generalized DMT Transceivers with Insufficient Guard Interval

EURASIP Journal on Advances in Signal Processing20042004:747654

  • Received: 28 February 2003
  • Published:


We propose a zero-forcing frequency domain block equalizer for discrete multitone (DMT) systems with a guard interval of insufficient length. In addition to the insufficient guard interval in the time domain, the equalizer takes advantage of frequency domain redundancy in the form of subcarriers that do not transmit any data. After deriving sufficient conditions for zero-forcing equalization, that is, complete removal of intersymbol and intercarrier interference, we calculate the noise enhancement of the equalizer by evaluating the signal-to-noise ratio (SNR) for each subcarrier. The SNRs are used by an adaptive loading algorithm. It decides how many bits are assigned to each subcarrier in order to achieve a maximum data rate at a fixed error probability. We show that redundancy in the time domain can be traded off for redundancy in the frequency domain resulting in a transceiver with a lower system latency time. The derived equalizer matrix is sparse, thus resulting in a low computational complexity.

Keywords and phrases

  • discrete multitone modulation
  • insufficient guard interval
  • zero-forcing frequency domain equalization
  • noise enhancement
  • system latency time

Authors’ Affiliations

Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, TX 79409, USA
Infineon Technologies Austria AG, Development Center Villach Siemens Strasse 2, Villach, 9500, Austria
Institute of Computer Engineering, Mannheim University, Mannheim, 68131, Germany


© Karp et al. 2004