Simulation of time variant room impulse responses

For many applications such as acoustic echo compensation, adaptive noise reduction or acoustic feedback control it is of great interest to simulate reproducibly a real, time variant room. One approach to describe the transient behavior of a room is the generation of a physical room model. To identify the variation of a room impulse response with time an alternative concept is presented, which uses the normalized least mean square (NLMS) algorithm excited by perfect sequences. The proposed general concept is capable to efficiently simulate the fluctuations of the room impulse response. The time variant simulation can be performed without the necessity to store large amounts of data by storing only the reaction of the unknown system instead of all sets of filter coefficients. The practical aspects of the new concept are pointed out for an acoustic echo control application