Indecomposable error sequences in multiuser detection

In this paper, we provide a graph-based characterization of the set of inde composable sequences that are useful in the computation of an upper bound t o error probability of maximum-likelihood (ML) detection in code-division m ultiple-access (CDMA) multiuser systems. We apply this characterization to a K-user symmetric system and to a two-user two-rate system. It leads to a precise calculation of the bound which is then compared to the performance of a decorrelator.