Modulation codes using mixed integer programming approach for multi-level holographic data storage

We propose modulation codes of 2/3 code rates for multi-level holographic data storage using mixed integer programming approach. In this paper, the signal intensities that are passed through the 4-level holographic channel are assumed as a four Gaussian mixture. Codeword selection problem with minimal symbol value difference between neighboring cells and near uniform symbol occurrence is formulated as a linear mixed integer programming problem and solved using IBM ILOG CPLEX ver.12.2.