Zigangirov, K. Sh. New asymptotic lower bounds on the free distance for time-constant convolutional codes. (English. Russian original) Zbl 0603.94014 Probl. Inf. Transm. 22, 104-111 (1986); translation from Probl. Peredachi Inf. 22, No. 2, 34-42 (1986). It is shown that the familiar Costello bound for the free distance is valid not only for time-varying but also for time-invariant convolutional codes with sufficiently ”long” edges. MSC: 94B10 Convolutional codes Keywords:lower bounds; Costello bound; time-invariant convolutional codes PDF BibTeX XML Cite \textit{K. Sh. Zigangirov}, Probl. Inf. Transm. 22, 104--111 (1986; Zbl 0603.94014); translation from Probl. Peredachi Inf. 22, No. 2, 34--42 (1986)