Time varying convolutional codes revisited

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations


There are several cases where the maximum free distance (MFD) time-invariant convolutional code of a given rate and total encoder memory does not meet the Heller bound or where the encoder that does meet the Heller bound is catastrophic. In order to find codes that meet the Heller bound, it is sometimes necessary to use time-varying convolutional codes. Some periodic time-varying convolutional codes with free distance greater than the best known time-invariant code of the same rate and total encoder memory are presented. These codes also achieve the Heller bound for the given code parameters. In addition, the use of time-varying encoders in order to achieve "spectral thinning" is explored.

Original languageEnglish (US)
Title of host publicationProceedings - 2001 IEEE Information Theory Workshop, ITW 2001
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages3
ISBN (Electronic)0780371194, 9780780371194
StatePublished - 2001
Event2001 IEEE Information Theory Workshop, ITW 2001 - Cairns, Australia
Duration: Sep 2 2001Sep 7 2001

Publication series

NameProceedings - 2001 IEEE Information Theory Workshop, ITW 2001


Other2001 IEEE Information Theory Workshop, ITW 2001

ASJC Scopus subject areas

  • Computer Networks and Communications
  • Information Systems
  • Computational Theory and Mathematics
  • Electrical and Electronic Engineering


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