Comparison of Generalized Sidelobe Canceller Structures Incorporating External Microphones for Joint Noise and Interferer Reduction

Abstract:
In this paper, we compare two extended generalized sidelobe canceller (GSC) structures, which exploit external microphones in conjunction with a local microphone array to improve the noise and interferer reduction. As a baseline algorithm we consider a local GSC using only the local microphones, for which the relative transfer function (RTF) vector of the target speaker is known. To incorporate the external microphones in a minimum power distortionless response beamformer, the RTF vector of the target speaker needs to be estimated. Since the estimation accuracy of this RTF vector depends on the signal-to-interferer ratio, the GSC with external speech references (GSC-ESR) pre-processes the external microphone signals to reduce the interferer. In a simplified extended structure, namely the GSC with external references (GSC-ER) no such pre-filtering operation is performed. Simulation results show that the GSC-ESR structure yields the best results in terms of noise and interferer reduction, especially in adverse conditions.