Holographic data storage (HDS) records binary bits in a two-dimensional page. Two-dimensional (2D) inter-symbol interference (ISI) according to the blur effect, thermal noise at detector, and a misalignment depending on pixel mismatch severely causes a poor performance. Therefore, various powerful modulation codes, error-correction codes (ECCs), and detectors have been proposed [4]. Specially, the soft-decision Viterbi decoding scheme consisting of modulation and Viterbi decoders has been studied for 2/4 modulation code in HDS systems [1], [2]. While the decoding method in [1], [2] showed outstanding bit error rate (BER) performance, its data rate is too low. In this paper, a new decoding method is proposed. The proposed method uses 4/6 modulation code [3], 3/4 convolutional code and the soft-decision Viterbi decoding scheme. Also, we propose a new reliability metric for 4/6 modulation code in order for the soft-decision Viterbi decoding scheme to use the branch metric on the trellis. Finally, we find a symbol mapping method for the modulation code, which provides a large free distance on the trellis for the enhanced error correcting capability.

© 2011 Optical Society of America

PDF Article


You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
Login to access OSA Member Subscription