A modified dithered signed-error constant-modulus algorithm for blind adaptive equalizer

Adaptive blind equalization has gained widespread use in communication receivers that operate without training signals. In particular, the constant modulus algorithm (CMA) has become a favourite 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 (SE-CMA) which have been found to lack the robustness properties of CMA. Alternatively a dithered signed-error of CMA (DSE-CMA) based on the judicious use of dither, has been proposed which results in algorithm with robustness properties nearly identical to those of CMA with the cost of the degradation in steady-state mean square error (MSE) performance. This paper presents a modified dithered signed-error version of CMA (MDSE-CMA) which is motivated by a reduction of the steady-state MSE of DSE-CMA without increase in its computational complexity