Graduate School and Research Center In communication systems

Christelle YEMDJI TCHASSI

Christelle YEMDJI TCHASSI
Christelle YEMDJI TCHASSI
Eurecom - Multimedia Communications 
Phd Student ( 2009 - 2013)
Alumni EURECOM

Thesis

Acoustic echo cancellation for single- and dual-microphone devices: Application to mobile devices

Responsible(s)

 

Mobile terminals are arguably the most popular telecommunications device of the present day.  With the expectation of use anytime, anywhere, mobile terminals are increasingly  used in adverse scenarios such as in hands-free mode and in noisy environments.  Speech quality is commonly degraded in such cases by the presence of acoustic echo and ambient noise. In consequence, mobile terminals are generally equipped with speech signal processing algorithms in order to assure acceptable speech quality.

Classical approaches to speech signal processing involve independent acoustic echo cancellation, noise suppression and post-filtering. While performance is generally acceptable, degradations are noticeable at low signal-to-echo ratios (hands-free scenarios) and computational complexity can be high.  Furthermore, while mobile terminals are increasingly equipped with multiple microphones, they are generally exploited for noise suppression alone, even if there is natural potential for combined noise suppression and echo control.

This thesis presents new combination and synchronization architecture for acoustic echo cancellation for single- and dual-microphone devices.  It moves beyond the current state-of-the-art by reducing computational complexity while improving performance in low signal-to-echo conditions.  The thesis also presents the first dual-microphone solution to double-talk detection.  These contributions pave the way for further applied research in speech processing; the novel architecture is readily extendible to multiple-microphone scenarios while respecting levels of computational efficiency required for integration in current mobile terminals.