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Trellis coded modulation based on time-varying mapping and encoders for utilizing a channel intersymbol interference

  • Ryuji Kohno
  • Choonsik Yim
  • Hideki Imai
Submitted Contributions Error Correcting Codes: Theory And Applications
  • 160 Downloads
Part of the Lecture Notes in Computer Science book series (LNCS, volume 508)

Abstract

This paper proposes and investigates a trellis coded modulation using time-varying mapping and encoders which is very useful to increase minimum Euclidean free distance(d free ) and obtain large coding gain by intentionally utilizing intersymbol interference(ISI) in a channel. If M-ary modulation signals are transmitted in a channel with ISI, the received signals will be mapped into more than M signal points due to ISI,i.e. a channel memory. In the presence of ISI, optimum allocation of distorted signal points due to ISI is derived so as to maximize Euclidean distance in the signal points at every instant considering the trellis diagram. In order to maintain the allocation in the state transition, a method to utilize time-varying mapping and encoders is described. In particular, the coded 4PSK using the time-varying mapping and encoders with a code rate 1/2 in the presence of ISI, 1+1/2D can achieve much larger d free and lower BER than the Ungerboeck's coded 4PSK using the time-invariant mapping and encoder in a channel without ISI, providing that their decoding complexity is equivalent. The improvement can increase as a constraint length of the encoder.

Keywords

Code Rate Signal Point Constraint Length Decode Complexity Intersymbol Interference 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Reference

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    Imai.H and Hirakawa.S.,”A new multilevel coding method using error-correcting codes,” IEEE Trans. Inform. Theory, vol.IT-23, May 1975.Google Scholar
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    Kohno. R, Imai. H, and Hatori. M,”Design of an automatic equalizer including a decoder of error-correcting code,” IEEE Trans. Commun. vol.COM-33, pp.1142–1146, 1985.Google Scholar
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    Kohno.R, Imai.H, and Pasupathy.S,”An automatic equalizer including a Viterbi decoder for a trellis coded modulation system,” Proc. IEEE International Conference on Acoustics, Speech and Signal Processing, pp.1368–1371, 1989.Google Scholar
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    Ungerboeck. G.,”Channel coding with multilevel/phase signals,” IEEE Trans. Inform. Theory, vol.IT-28,1,pp.55–67, Jan. 1982Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 1991

Authors and Affiliations

  • Ryuji Kohno
    • 1
  • Choonsik Yim
    • 1
  • Hideki Imai
    • 1
  1. 1.Division of Electrical and Computer Engineering Faculty of EngineeringYokohama National UniversityYokohamaJapan

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