Performance of MMSE turbo equalization using outer LDPC coding for magnetic recording channels

We investigate the performance of minimum mean-square error turbo-equalization for LDPC-coded transmission over intersymbol-interference channels. The EXIT-chart technique is used to study the effect of code rate on the convergence of the turbo-equalization process. The analysis is conducted for partial-response channels of various types and for the magnetic recording channel. Performance results obtained from simulations show good agreement with the EXIT-chart analysis. They indicate that for applications requiring high code rates equalizer-based detection may suffer from a nonnegligible loss in performance as compared with maximum a posteriori detection.