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  • Research Article
  • Open Access

Efficient Channel Shortening Equalizer Design

  • 1Email author,
  • 2,
  • 2 and
  • 1
EURASIP Journal on Advances in Signal Processing20032003:906491

https://doi.org/10.1155/S1110865703307024

  • Received: 6 February 2003
  • Published:

Abstract

Time-domain equalization is crucial in reducing channel state dimension in maximum likelihood sequence estimation and intercarrier and intersymbol interference in multicarrier systems. A time-domain equalizer (TEQ) placed in cascade with the channel produces an effective impulse response that is shorter than the channel impulse response. This paper analyzes two TEQ design methods amenable to cost-effective real-time implementation: minimum mean square error (MMSE) and maximum shortening SNR (MSSNR) methods. We reduce the complexity of computing the matrices in the MSSNR and MMSE designs by a factor of 140 and a factor of 16 (respectively) relative to existing approaches, without degrading performance. We prove that an infinite-length MSSNR TEQ with unit norm TEQ constraint is symmetric. A symmetric TEQ halves FIR implementation complexity, enables parallel training of the frequency-domain equalizer and TEQ, reduces TEQ training complexity by a factor of 4, and doubles the length of the TEQ that can be designed using fixed-point arithmetic, with only a small loss in bit rate. Simulations are presented for designs with a symmetric TEQ or target impulse response.

Keywords

  • multicarrier modulation
  • channel shortening
  • time-domain equalization
  • efficient computation
  • symmetry

Authors’ Affiliations

(1)
School of Electrical and Computer Engineering, Cornell University, Ithaca, NY 14853, USA
(2)
Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX 78712-1084, USA

Copyright

© Copyright © 2003 Hindawi Publishing Corporation 2003

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