Real-time implementation of an efficient RLS algorithm based on IIR filter for acoustic echo cancellation

An efficient acoustic echo canceller has been proposed for hands-free communication systems which use a recursive least squares (RLS) algorithm. It also employ an infinite impulse response (IIR) filter based on output error method. The proposed IIR-RLS filter is more suitable for modeling real systems due to its pole-zero structure and it is required fewer number of filter coefficients to identify the time-varying echo path as compared to the traditional FIR-NLMS filter. However, with non-stationary long durations signals the proposed IIR-RLS filter suffers from instability problem. To avoid this problem, auto covariance matrix resetting was employed. Furthermore, the proposed system has been implemented in real-time in a real environment using National Instruments NI-PXI-1042Q controller system and data acquisition input card PXI-4472. Practical results, show that the proposed algorithm has the local minimum solutions and remain stable.