On classes of convolutional codes that are not asymptotically catastrophic
Denote by w(0) the minimum average weight per edge over all nonzero cycles in the state diagram for a convolutional code, and assume that a technique is available for generating canonical parity-cheek matrices for codes with increasing degree m. The obtained class of codes is asymptotically catastrophic if w(0) approaches zero for large m. In this correspondence we prove the existence of convolutional code classes that are not asymptotically catastrophic by providing explicit constructions of codes with nonzero w(0) or all m.
convolutional codes asymptotically catastrophic code constructions