On the SOVA for extremely high code rates over partial response channels

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In this paper, we extend the derivation of the iterative soft-output Viterbi algorithm (SOVA) for partial response (PR) channels, and modify its decoding process such that it works consistently for arbitrary high code rates, e.g., rate 64/65. We show that the modified SOVA always outperforms the conventional SOVA that appears in the literature with a significant difference for high code rates. It also offers a significant cut down in the trace-back computations. We further examine its performance for parallel and serial concatenated codes on a preceded Class IV partial response (PR4) channel. Code rates of the form k0/k0+1 (k0 = 4, 8, and 64) are considered. Our simulations indicate that the loss suffered by the modified SOVA, relative to the APP algorithm, is consistent for all code rates and is at most 1.2 dB for parallel concatenations and at most 1.6 dB for serial concatenations at Pb = 10-5.

Original languageEnglish
Pages (from-to)1-6
Number of pages6
JournalJournal of Communications and Networks
Issue number1
Publication statusPublished - Mar 2003



  • Decoding depth
  • Iterative decoding
  • Parallel and serial concatenation
  • Partial response signaling
  • SOVA

ASJC Scopus subject areas

  • Information Systems
  • Computer Networks and Communications

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