The dual of convolutional codes over $\mathbb{Z}_{p^r}$

An important class of codes widely used in applications is the class of convolutional codes. Most of the literature of convolutional codes is devoted to convolutional codes over finite fields. The extension of the concept of convolutional codes from finite fields to finite rings have attracted much attention in recent years due to fact that they are the most appropriate codes for phase modulation. However convolutional codes over finite rings are more involved and not fully understood. Many results and features that are well-known for convolutional codes over finite fields have not been fully investigated in the context of finite rings. In this paper we focus in one of these unexplored areas, namely, we investigate the dual codes of convolutional codes over finite rings. In particular we study the p-dimension of the dual code of a convolutional code over a finite ring. This contribution can be considered a generalization and an extension, to the rings case, of the work done by Forney and McEliece on the dimension of the dual code of a convolutional code over a finite field. Mohammed El Oued FSMMath Department, University of Monastir, Monastir 5050, Tunisia e-mail: [email protected] Diego Napp CIDMA Center for Research and Development in Mathematics and Applications, Department of Mathematics, University of Aveiro, Aveiro, Portugal e-mail: [email protected] Raquel Pinto CIDMA Center for Research and Development in Mathematics and Applications, Department of Mathematics, University of Aveiro, Aveiro, Portugal e-mail: [email protected] Marisa Toste CIDMA Center for Research and Development in Mathematics and Applications, Instituto Politcnico de Coimbra-ESTGOH, Coimbra, Portugal e-mail: [email protected]