Reducing complexity of tail-biting trellises
For researchers in coding theory and trellis-based decoding, this provides a theoretical framework for simplifying tail-biting trellises, though the results are incremental.
The paper addresses the problem of reducing complexity in tail-biting trellises by identifying conditions for local reducibility and presenting a necessary and sufficient criterion for local irreducibility.
It is shown that a trellis realization can be locally reduced if it is not state-trim, branch-trim, proper, observable, and controllable. These conditions are not sufficient for local irreducibility. Making use of notions that amount to "almost unobservability/uncontrollability", a necessary and sufficient criterion of local irreducibility for tail-biting trellises is presented.