Concurrent constant modulus algorithm and soft decision directed scheme for fractionally-spaced blind equalization

The paper proposes a concurrent constant modulus algorithm (CMA) and soft decision-directed (SDD) scheme for low-complexity blind equalization of high-order quadrature amplitude modulation channels. Simulation using a fractionally spaced equalization setting is used to compare the proposed scheme with the recently introduced state-of-art concurrent CMA and decision-directed (DD) scheme. The proposed CMA+SDD blind equalizer is shown to have simpler computational complexity per weight update, faster convergence speed, and slightly improved steady-state equalization performance, compared with the CMA+DD blind equalizer.