Time- and frequency-domain X-block least-mean-square algorithms for active noise control

In this paper, X-block least-mean-square (LMS) adaptive algorithms are presented for time-and frequency-domain active noise control. The algorithms are essentially extensions of the well-known block-mean-square (BLMS) algorithms to the filtered-X structure. The X-filter block algorithms are formulated for time- and frequency-domain implementation. In addition, time varying convergence factors are derived for all the X-block LMS algorithms presented. Time-varying convergence factors improve the adaptation speed of the algorithm at the expense of additional computational complexity. The complexity of the proposed algorithms is also discussed and the computational efficiency of frequency-domain implementations is evaluated with different filter lengths. The algorithms are applied to active noise control and results are presented with computer simulations and real-time experiments.