Performance bounds for cochannel interference cancellation within the current GSM standard

The performance of maximum-likelihood sequence estimation (MLSE) is bounded (and often approximated well) by the matched filter bound (MFB). In this p aper, we first show how the linearized GMSK modulation of GSM can be reform ulated to have a real symbol constellation, leading to a two-channel aspect due to the in-phase (I) and in-quadrature (Q) components of the received s ignal. More channels can be added by oversampling and/or the use of multipl e sensors (antennas, polarizations). Given this model, we present the MFB f or MLSE single-user detection in the presence of interferers that are model ed as colored Gaussian noise. The MLSE is assumed to employ noise correlati on information that in general may differ from the true one (e.g. by simpli fying spatio-temporal correlations to spatial correlations only). One of th e conclusions is that properly taking into account the spatio-temporal corr elation of the interference leads to much improved performance (MFB) compar ed to purely spatial approaches. Another conclusion is that the excess band width in GMSK provides some useful channel diversity. (C) 2000 Elsevier Sci ence B.V. All rights reserved.