DSP-based solution for ambient noise reduction in mobile phones

Using a mobile handset in noisy environments makes the far-end speech difficult to be perceived from the near-end user perspective. As he is surrounded by a loud background noise, the handset user needs to concentrate hard to understand the far-end speaker conversation. Ambient noise reduction algorithms provide an efficient solution to build a silent zone between the handset loudspeaker and the user ear, thus improving the speech understanding for the near-end speaker. This paper presents a description of an innovative ambient noise reduction system developed on a TI TMS320C54x DSP. This combines both theoretical and experimental considerations, raising potential issues that may be encountered when implementing these applications on a real system. It is shown that the advanced architecture of the TI TMS320C54x DSP makes the ambient noise reduction application possible in the same CPU performing time wireless digital cellular baseband processing.