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Volume 59, Nº 3 (2023)

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Coding Theory

Convolutional Codes with Optimum Bidirectional Distance Profile

Stanojevi´c I., Senk V.

Resumo

We define the bidirectional distance profile (BDP) of a convolutional code as the minimum of the distance profiles of the code and its corresponding “reverse” code. We present tables of codes with the optimum BDP (OBDP), which minimize the average complexity of bidirectional sequential decoding algorithms. The computer search is accelerated by the facts that optimum distance profile (ODP) codes of larger memory must have ODP codes of smaller memory as their “prefixes”, and that OBDP codes can be obtained by “concatenating” ODP and reverse ODP codes of smaller memory. We compare the performance of OBDP codes and other codes by simulation.

Problemy peredači informacii. 2023;59(3):3-25
pages 3-25 views

On the Classification of Completely Regular Codes with Covering Radius Two and Antipodal Duals

Borges J., Zinov'ev V., Zinov'ev D.

Resumo

We classify all linear completely regular codes which have covering radius ρ=2">ρ=2 and whose dual are antipodal. For this, we firstly show several properties of such dual codes, which are two-weight codes with weights d">d and n">n.

Problemy peredači informacii. 2023;59(3):26-39
pages 26-39 views