Singular value analysis of space-time equalization in the GSM mobile system

Singular value analysis of a GMSK-modulated signal such as employed by GSM reveals that it admits a reasonably accurate linear model, enabling the use of linear space-time equalizers to retrieve the data symbols. The analysis also shows that one antenna does not provide sufficient resolution to allow estimation of the channel length, so that the performance of the equalizers is limited. An algorithm is proposed for the blind space-time equalization and separation of multiple co-channel GMSK signals, based on their fixed symbol rate, finite alphabet and constant modulus properties.