Noise-predictive turbo equalization for partial-response channels

We present a modified turbo equalization scheme that accounts for the colored noise present in high-density partial-response equalization systems. The scheme uses soft information from previous turbo iterations to selectively predict the noise before the next iteration. Simulation results on a PR4 target with low-density parity check (LDPC) coding show that the proposed scheme with up to 2-tap prediction substantially outperforms standard turbo equalization schemes for LDPC-coded EPR4 and PR4 channels.