A novel variable tap-length algorithm for linear adaptive filters

The tap-length is an important structural parameter of the linear FIR adaptive filter. Although the optimum tap-length that balances the performance and complexity varies with the scenario, most current adaptive filters fix the tap-length at some compromise value, making them inefficient to implement, especially in time varying scenarios. In this paper, we propose a novel gradient search based variable tap-length algorithm using the concept of the pseudo fractional tap-length, and show that the new algorithm can converge to the optimum tap-length in the mean. Results of computer simulations are also provided to verify the analysis in this paper.