Acoustic Echo Cancellation for Multiple Reproduction Channels: From First Principles to Real-Time Solutions

Multichannel acoustic echo cancellation (MCAEC) is a key technology whenever hands-free and full-duplex communication in modern systems with multichannel sound reproduction is desired. Although the basic principle of echo cancellation has been well known for several decades, the multichannel case poses some additional and fundamentally different challenges. Moreover, there are even some notable differences between the two-channel case and the general multichannel case which has been addressed bit by bit only in recent years. The aim of this paper is twofold. On the one hand, after a brief review of the problem of multichannel acoustic echo cancellation, this paper gives an outline of how the problem may be tackled based on some fundamental principles. In this sense, the presentation in this paper brings together for the first time ideas from system theory, information theory, psychoacoustics, and also wave physics. Based on this framework, and as the other main contribution, we present in this paper some recent advances in the field of MCAEC. Thereby, important issues in the case of more than two channels are emphasized. Finally, as an outlook, we touch on our ongoing work towards MCAEC for massive multichannel sound reproduction, such as wave field synthesis.