The Soft-Feedback ISI Canceller-Based Turbo Equalizer for Multilevel Modulations

摘要

In this paper, we investigate the soft-feedback equalizer (SFE) proposed by Lopes et al. for multilevel modulations. The SFE is based on intersymbol interference canceller structure and is compared to both soft-decision feedback turbo equalizer (SDFE) and the exact solution of MMSE linear equalizer (Exact-MMSE-LE) by means of EXIT chart analysis and BER simulations. Interesting results reveal that, for multilevel modulations, the SFE not only exhibits the same low complexity, low SNR threshold and fast convergence as SDFE but also reaches matched filter bound after a large number of iterations.