Minimum mean square error equalization using priors for two-dimensional intersymbol interference

Joint iterative equalization and decoding schemes are proposed for two-dimensional intersymbol interference channels. Equalization is performed using the minimum mean squared error criterion. Three linear equalizers are proposed. The exact equalizer, a spatially and temporally varying equalizer, has performance similar to schemes based on message-passing and has lower complexity. To save further on computational cost, time-invariant implementations of the exact equalizer are also proposed. Extrinsic information transfer charts are used to analyze the equalizers. A density evolution algorithm using a Gaussian approximation is proposed and used to study the trade-off between computational cost and performance for different decoding schedules.