Theoretical noise reduction limits of the generalized sidelobe canceller (GSC) for speech enhancement

In this paper we present an analysis of the generalized sidelobe canceller (GSC). It can be shown that the theoretical limits of the noise reduction performance depend only on the auto- and cross-spectral densities of the input signals. Furthermore, we compute the limits of the noise reduction performance for the theoretically determined diffuse noise held, which is an approximation for reverberant rooms. Our results will show that the GSC cannot reduce noise further than 1dB. These results were verified by simulation of reverberant environments. Only in sound-proof rooms with a reverberation time less than 100ms the GSC performs well.