Title :
Local minima escape transients of CMA
Author :
Frater, Michael R. ; Johnson, C. Richard, Jr.
Author_Institution :
Dept. of Electr. Eng., Australian Defence Force Acad., Canberra, ACT, Australia
Abstract :
We examine the implications of our recent analysis of the local minima escape behavior of the Godard (or CMA) blind equalizer. This analysis suggests asymptotic estimates for the expected value of the escape time when leaving the region of attraction of local equilibria. For a particular source, channel, and equalizer local minimum parameterization, the log of the inverse of the mean escape time is estimated to be proportional to a weighted sum of the stepsize and the channel noise variance. We examine the validity of the functional form of this relationship for two examples. This experimental evidence corroborates our earlier analysis and suggests that the mean time to escape can be very large for the Godard (1980) algorithm (also known as the constant modulus algorithm)
Keywords :
adaptive equalisers; adaptive filters; filtering theory; telecommunication channels; transients; CMA blind equalizer; Godard algorithm; Godard blind equalizer; asymptotic estimates; channel noise variance; filtering; local equilibria; local minima escape transients; local minimum parameterization; mean escape time; source; stepsize; weighted sum; Algorithm design and analysis; Blind equalizers; Delay; Digital communication; Digital filters; Fluctuations; Least squares approximation; Polynomials; Signal to noise ratio; Telephony;
Conference_Titel :
Acoustics, Speech, and Signal Processing, 1994. ICASSP-94., 1994 IEEE International Conference on
Conference_Location :
Adelaide, SA
Print_ISBN :
0-7803-1775-0
DOI :
10.1109/ICASSP.1994.390096