Title:
Nonlinear acoustic echo cancellation

dc.contributor.advisor Zhou, G. Tong
dc.contributor.advisor Ma, Xiaoli
dc.contributor.author Shi, Kun en_US
dc.contributor.committeeMember David V. Anderson
dc.contributor.committeeMember James Stevenson Kenney
dc.contributor.committeeMember Liang Peng
dc.contributor.committeeMember William D. Hunt
dc.contributor.department Electrical and Computer Engineering en_US
dc.date.accessioned 2009-01-22T15:58:25Z
dc.date.available 2009-01-22T15:58:25Z
dc.date.issued 2008-11-10 en_US
dc.description.abstract The objective of this research is to presents new acoustic echo cancellation design methods that can effectively work in the nonlinear environment. Acoustic echo is an annoying issue for voice communication systems. Because of room acoustics and delay in the transmission path, echoes affect the sound quality and may hamper communications. Acoustic echo cancellers (AECs) are employed to remove the acoustic echo while keeping full-duplex communications. AEC designs face a variety of challenges, including long room impulse response, acoustic path nonlinearity, ambient noise, and double-talk situation. We investigate two parts of echo canceller design: echo cancellation algorithm design and control logic algorithm design. In the first part, our work focuses on the nonlinear adaptive and fast-convergence algorithms. We investigate three different structures: predistortion linearization, cascade structure, and nonlinear residual echo suppressor. Specifically, we are interested in the coherence function, since it provides a means for quantifying linear association between two stationary random processes. By using the coherence as a criterion to design the nonlinear echo canceller in the system, our method guarantees the algorithm stability and leads to a faster convergence rate. In the second part, our work focuses on the robustness of AECs in the presence of interference. With regard to the near-end speech, we investigate the double-talk detector (DTD) design in conjunction with nonlinear AECs. Specifically, we propose to design a DTD based on the mutual information (MI). We show that the advantage of the MI-based method, when compared with the existing methods, is that it is applicable to both the linear and nonlinear scenarios. With respect to the background noise, we propose a variable step-size and variable tap-length least mean square (LMS) algorithm. Based on the fact that the room impulse response usually exhibits an exponential decay power profile in acoustic echo cancellation applications, the proposed method finds optimal step size and tap length at each iteration. Thus, it achieves faster convergence rate and better steady-state performance. We show a number of experimental results to illustrate the performance of the proposed algorithms. en_US
dc.description.degree Ph.D. en_US
dc.identifier.uri http://hdl.handle.net/1853/26704
dc.publisher Georgia Institute of Technology en_US
dc.subject Acoustic echo cancellation en_US
dc.subject Adaptive filter en_US
dc.subject Nonlinearity en_US
dc.subject Nonlinear acoustic echo en_US
dc.subject Double-talk detection en_US
dc.subject Step-size control en_US
dc.subject.lcsh Echo suppression (Telecommunication)
dc.subject.lcsh Acoustical engineering
dc.subject.lcsh Speech processing systems
dc.subject.lcsh Nonlinear acoustics
dc.title Nonlinear acoustic echo cancellation en_US
dc.type Text
dc.type.genre Dissertation
dspace.entity.type Publication
local.contributor.advisor Ma, Xiaoli
local.contributor.advisor Zhou, G. Tong
local.contributor.corporatename School of Electrical and Computer Engineering
local.contributor.corporatename College of Engineering
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