Iterative detection of 2-dimensional ISI channels

The performance of iterative detection methods is evaluated for the binary-input two-dimensional (2D), linear inter-symbol interference (ISI) channel with additive white Gaussian noise (AWGN). All of the proposed detection schemes involve message passing between detectors operating iteratively on the rows and columns of the 2D channel observations. Simulation results indicate that both the constituent detector performance and the loopiness of the underlying graphical model affect the iterative detector performance. Results are presented for a class of 3-tap, 2D channels defined by a single parameter. These indicate that straightforward application of turbo equalization to the 2D ISI problem performs poorly, but with ad-hoc enhancements, maximum likelihood (ML) detection is approached, to within 0.5 dB.