Keunhwi KOO¹, Soo-Yong KIM^1,2, Jae Jin JEONG¹, and Sang Woo KIM^1,3*

¹Department of Electrical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk 790-784, Korea
²M&C Development Team, System LSI Division, Samsung Electronics Co., Ltd., Yongin, Gyeonggi 446-711, Korea
³Department of Creative IT Excellence Engineering and Future IT Innovation Laboratory, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk 790-784, Korea

(Received November 25, 2013; Accepted March 6, 2014)

This study introduces a two-dimensional (2D) partial response maximum likelihood (PRML) method to reconstruct a degraded data page having 2D inter-symbol interference for holographic data storage. The proposed 2D PRML method consists of 2D partial response (PR) target, 2D equalizer using least mean square algorithm, and 2D soft output Viterbi algorithm (SOVA) having just two one-dimensional (1D) SOVAs in horizontal and vertical directions. To accurately organize a trellis diagram of the 1D SOVA in structural accordance with the 2D PR target, this study proposes the self-reference process for the extrinsic information in the 1D SOVA. Finally, simulation results show that the proposed method has bit error rate performance similar to that of modified 2D SOVA having four 1D SOVAs despite the relatively low computational complexity. Moreover, parallel processing is possible in the two 1D SOVAs through the self-reference process.

Key words: holographic data storage, data page, 2D PRML, 2D equalizer, 2D SOVA

^*E-mail address: swkim@postech.edu