Patent ID: 8760782

Claim:
A disk drive comprising: a processor configured to decode data written over a plurality of tracks of a disk using joint self-iterating soft equalization and an iterative turbo two-dimensional (2-D) maximum a-posteriori (MAP)-based detection, the processor being coupled to a memory and being configured to: receive input samples from a data channel; perform soft self-iterating linear 2-D minimum mean square error (MMSE) equalization on the received input samples; provide a 2-D equalization filter having a predetermined order that defines a number of rows and columns; compute MMSE estimates for coefficients of the provided 2-D equalization filter based on a-priori values, mean of the a-priori values, the 2-D equalization filter and the received input samples; update the coefficients of the 2-D equalization filter using a variance based on the a-priori values when carrying out a first iteration and based on an extrinsic Log Likelihood Ratio (LLR) when carrying out second and subsequent iterations; determine whether individual bits in the input samples are 0s or 1s using the updated coefficients; compute an output LLR of each individual received sample based on the computed MMSE estimate, the mean and the variance, and compute the extrinsic LLR by subtracting a priori LLR from the output LLR.