Dithered Signed-Error CMA: The Complex-Valued Case
P. Schniter and C.R. Johnson, Jr.
Abstract
Adaptive blind equalization has gained widespread
use in communication systems that operate without training signals.
In particular, the Constant Modulus Algorithm (CMA) has become a
favorite of practitioners due to its LMS-like complexity and
desirable robustness properties. The desire for further reduction
in computational complexity has motivated signed-error versions of
CMA, which have been found to lack the robustness properties of
CMA. Previously we have presented a simple modification of
real-valued signed-error CMA, based on the judicious use of dither,
that results in an algorithm with robustness properties nearly
identical to those of real-valued (unsigned) CMA. This paper
extends those results to the complex-valued case.
