On the use of the FNTF algorithm in subband acoustic echo cancellation

The fast Newton transversal filter (FNTF) family of adaptive filtering algo rithms bridges the performance gap between the standard normalized least-me an-square (NLMS) and fast recursive least-squares (FRLS) algorithms by allo wing the use of linear predictors with variable orders. Recently, it has be en shown that the FNTF is an effective scheme for fullband acoustic echo ca ncellation (AEC) of short echo paths (e.g., mobile context). In this paper, the merits of FNTF for subband AEC of the long echo paths typically associ ated with the use of hands-free audio terminals in offices (e.g., audioconf erencing) are investigated. To this end, a stabilized version of FNTF is in corporated in an oversampled subband structure based on Weaver single-sideb and (SSB) modulation. The performance of the resulting subband AEC system i s evaluated in terms of convergence speed and computational complexity. The results point to some fundamental limitations of FNTF in this application.