An Efficient RLS Algorithm For Output-Error Adaptive IIR Filtering And Its Application To Acoustic Echo Cancellation

In this letter, an efficient recursive least squares (RLS) algorithm using infinite impulse response (IIR) filter for acoustic echo cancellation (AEC) is proposed. The RLS adaptive filter is naturally extended from the finite impulse response (FIR) structure to the IIR structure. One of the main advantages of an IIR RLS filter is that a long-delay echo can be synthesized by a relatively small number of filter coefficients leading to lesser computational complexity. In addition it is more suitable for modeling physical systems, due to its pole-zero structure, over their FIR counterparts. To investigate the tracking performance and the stability of the proposed IIR RLS filter in a practical implementation, real data for far end speech signal and its echo were used in car environment. The proposed algorithm is shown to have global convergence. To demonstrate the effectiveness of the proposed IIR RLS filter, it is compared to the usual FIR RLS filter. The good performance of the proposed IIR RLS algorithm for AEC have been verified via computer simulations