Estimation of time-variant acoustic feedback paths in in-car communication systems

In-car communication systems aim at improving the speech communication inside a vehicle by picking up the talking passenger's voice by means of microphones and playing it back over loudspeakers that are located close to the listening passengers. Because of this closed-loop operation, system instability caused by acoustical feedback is a limiting factor for the maximum possible system support. In this contribution, we present a feedback cancellation algorithm based on the NLMS algorithm for estimating the frequency responses of the multiple, time-variant feedback paths. The step-size parameter is calculated time- and frequency dependently and signal decorrelation, which is necessary for convergence of the filters, is performed by a phase modulation filter for frequency shifting. Measurements in a test car prove the effectiveness of the approach in the in-car communication application, even in the presence of background noise.

[1]  Jesper Jensen,et al.  An improved probe noise approach for acoustic feedback cancellation , 2012, 2012 IEEE 7th Sensor Array and Multichannel Signal Processing Workshop (SAM).

[2]  Jesper Jensen,et al.  On the use of a phase modulation method for decorrelation in acoustic feedback cancellation , 2012, 2012 Proceedings of the 20th European Signal Processing Conference (EUSIPCO).

[3]  Francesco Piazza,et al.  A Combined Approach for Channel Decorrelation in Stereo Acoustic Echo Cancellation Exploiting Time-Varying Frequency Shifting , 2013, IEEE Signal Processing Letters.

[4]  Wei-Yong Yan,et al.  New Insights Into Optimal Acoustic Feedback Cancellation , 2013, IEEE Signal Processing Letters.

[5]  Jaime Lloret,et al.  Direct method with random optimization for loudspeaker equalization using IIR parametric filters , 2004, 2004 IEEE International Conference on Acoustics, Speech, and Signal Processing.

[6]  Gerhard Schmidt,et al.  Signal processing for in-car communication systems , 2006, Signal Process..

[7]  Israel Cohen,et al.  Dereverberation and Residual Echo Suppression in Noisy Environments , 2008 .

[8]  Henning Puder,et al.  Step-size control for acoustic echo cancellation filters - an overview , 2000, Signal Process..

[9]  Jacob Benesty,et al.  A better understanding and an improved solution to the specific problems of stereophonic acoustic echo cancellation , 1998, IEEE Trans. Speech Audio Process..

[10]  Nicolas Juillerat,et al.  Low latency audio pitch shifting in the frequency domain , 2010, 2010 International Conference on Audio, Language and Image Processing.

[11]  Mark A Beach,et al.  Sensor Array and Multichannel Signal Processing Workshop, 2002 , 2002 .

[12]  Marc Moonen,et al.  Fifty Years of Acoustic Feedback Control: State of the Art and Future Challenges , 2011, Proceedings of the IEEE.

[13]  Akinori Nishihara,et al.  On delay-based technique for acoustic feedback cancellation in digital hearing aids , 2013, 2013 IEEE 56th International Midwest Symposium on Circuits and Systems (MWSCAS).

[14]  Gerhard Schmidt,et al.  Application of Frequency Shifting in In-Car Communication Systems , 2014, ITG Symposium on Speech Communication.

[15]  Francesco Piazza,et al.  A Real-Time Dual-Channel Speech Reinforcement System for Intra-Cabin Communication , 2013 .

[16]  Emanuel A. P. Habets,et al.  Joint Dereverberation and Residual Echo Suppression of Speech Signals in Noisy Environments , 2008, IEEE Transactions on Audio, Speech, and Language Processing.

[17]  Eduardo Lleida,et al.  Speech reinforcement system for car cabin communications , 2005, IEEE Transactions on Speech and Audio Processing.

[18]  Gerald Enzner,et al.  Trends in adaptive MISO system identification for multichannel audio reproduction and speech communication , 2013, 2013 8th International Symposium on Image and Signal Processing and Analysis (ISPA).