Uma contribuição a classe dos codigos geometricamente uniformes




In this research we present extensions oí code constructions whose codes belong to the class oí geometrically uniíorm codes. We consider two characterizations oí signal sets matched to groups. The first characterization is derived írom a noncommutative group which is the semidirect product oí a commutative group by a cyclic group oí even order. The second characterization is derived írom an algorithm based on the concept oí a d-chain. We propose a multilevel construction oí codes over the group Zq. These codes are used in the multilevel construction oí sphere packings, which is an extension oí Costa e Silva and Palazzo s binary construction [10]. As a result, new Euclidean-space codes and sphere packings are presented. In dimensions 68 and 72, new record oí densities appear to have been achieved


teoria da codificação isometria (matematica) codigos de controle de erros (teoria da informação) teoria dos reticulados teoria dos grupos teoria da modulação

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