Some periodic convolutional codes better than any fixed code (Corresp.)
M. Mooser · IEEE Transactions on Information Theory · 1983
Some(n_{o}=2; k_{o}=1)noncatastrophic periodic convolutional codes with memoryM=4are given that have the same free distance,d_{\infty}, as the best fixed code but have both a smaller number of paths of weightd_{\infty}per time instant and a smaller average number of information bit errors per such path for periodsT=2, 3, 4, and5. It is also shown that an(n_{0}, k_{0})code of periodTis equivalent to a fixed code with parameters(Tn_{0}, Tk_{0}).