Cochannel interference cancellation within the current GSM standard

Abstract

The performance of maximum likelihood sequence estimation (MLSE) is bounded (and often approximated well) by the matched filter bound (MFB). In this paper, we first show how the GMSK modulation of GSM can be linearized and reformulated to have a real symbol constellation, leading to a two-channel aspect due to the in-phase and in-quadrature components of the received signal. More channels can be added by oversampling and/or the use of multiple antennas. We present the MFB for this model in the presence of colored noise (interferers) for MLSE that employs noise correlation information (that in general may differ from the true one). We show that by properly taking into account the noise correlation leads to a much improved MFB.