Soft-Encoding Scheme of 3/4 Tone-Controllable Code for Channel Iteration of Low-Density Parity-Check Code on the Holographic Data Storage

摘要

In turbo equalization for holographic data storage (HDS) systems, an iterate-back signal must pass through a modulation coding process for channel iteration since the iterate-back signal is a demodulated signal and the input of a detector is modulated data. Also, the iterate-back signal is a soft-value, so the soft-input and soft-output (SISO) must be treated by a modulation code. A 3/4 tone-controllable (TC) code can control the ratio of ON and OFF pixels on each data page. The memory capacity of a holographic data storage system can be increased if we use a TC code. In this paper, we concatenate a 3/4 TC code and LDPC code, and then simulate the turbo equalization performance on a HDS channel. A SISO 3/4 TC code is needed for this simulation. Therefore, we propose a soft-encoding scheme for a SISO 3/4 TC code.