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

• Main Authors: Trautmann Steffen, Fliege Norbert J, Karp Tanja
• Format: Article
• Language: English
• Published: SpringerOpen 2004-01-01
• Series: EURASIP Journal on Advances in Signal Processing
• Subjects: discrete multitone modulation; insufficient guard interval; zero-forcing frequency domain equalization; noise enhancement; system latency time
• Online Access: http://dx.doi.org/10.1155/S1110865704311169

<p/> <p>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.</p>