On viewing block codes as finite automata

Shankar, Priti and Dasgupta, Amitava and Deshmukh, Kaustubh and Rajan, Sundar B (2003) On viewing block codes as finite automata. In: Theoretical Computer Science, 290 (3). pp. 1775-1797.

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Abstract

Block codes are viewed from a formal language theoretic perspective. It is shown that properties of trellises for subclasses of block codes called rectangular codes follow naturally from the Myhill Nerode theorem. A technique termed subtrellis overlaying is introduced with the object of reducing decoder complexity. Necessary and sufficient conditions for trellis overlaying are derived from the representation of the block code as a group, partitioned into a subgroup and its cosets. The conditions turn out to be simple constraints on coset leaders. It is seen that overlayed trellises are tail-biting trellises for which decoding is generally more efficient than that for conventional trellises. Finally, a decoding algorithm for tail-biting trellises is described, and the results of some simulations are presented.

Item Type:	Journal Article
Publication:	Theoretical Computer Science
Publisher:	Elsevier
Additional Information:	Copyright of this article belongs to Elsevier.
Keywords:	Block codes;Tail-biting trellis;Decoder complexity;Maximum likelihood decoding
Department/Centre:	Division of Electrical Sciences > Computer Science & Automation
Date Deposited:	31 May 2006
Last Modified:	19 Sep 2010 04:28
URI:	http://eprints.iisc.ac.in/id/eprint/7227

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