Acoustic signal gain enhancement and speech recognition improvement in smartphones using the REF beamforming algorithm

Smartphones deploy multiple microphones to reduce background noise, reverberation and interferences. This paper presents the regulated Frost beamformer (REF) for acoustic gain enhancement and speech recognition improvement in smartphones. Conventional and adaptive beamformers were investigated with recourse to the acoustic transducer specifications of the Samsung Galaxy S2 device. The REF algorithm outperforms the time delay and Frost beamformers by over 5 dB and 2 dB respectively. Moreover, the minimum array gain is 5 dB (REF) as opposed to the floor gain of 2 dB. Compared with the delay-and-sum and Frost beamformers, the output waveform of the REF beamformer is the closest to the desired signal.