Title :
Adaptive step size sign algorithm for application to adaptive filtering in digital QAM communications
Author :
Koike, Shin´ichi
Author_Institution :
NEC Corp., Tokyo, Japan
Abstract :
A new adaptive step size control algorithm is proposed to be combined with the sign algorithm for use in complex-valued adaptive filters for application to QAM communications. The algorithm, ASSSA, is fully analyzed to yield a set of difference equations for calculating the transient behavior, hence the steady-state performance, of the filter convergence in terms of excess mean squared error (EMSE). An approximation method for multilevel QAM is further proposed to reduce the amount of computation. The results of experiment with some examples verify the effectiveness of the proposed ASSSA in significantly improving the convergence rate, and also show that the theoretical convergence is in good agreement with that of simulations, which validates the analysis
Keywords :
adaptive control; adaptive filters; approximation theory; convergence of numerical methods; difference equations; digital communication; mean square error methods; quadrature amplitude modulation; transient response; ASSSA; EMSE; adaptive filtering; adaptive step size control; approximation method; complex-valued adaptive filters; difference equations; digital communications; excess mean squared error; filter convergence; multilevel QAM; sign algorithm; steady-state performance; transient behavior; Adaptive control; Adaptive filters; Algorithm design and analysis; Convergence; Difference equations; Performance analysis; Programmable control; Quadrature amplitude modulation; Size control; Transient analysis;
Conference_Titel :
Acoustics, Speech, and Signal Processing, 2001. Proceedings. (ICASSP '01). 2001 IEEE International Conference on
Conference_Location :
Salt Lake City, UT
Print_ISBN :
0-7803-7041-4
DOI :
10.1109/ICASSP.2001.940659
