Search

The principal target of this study is to enhance the performance of the 4-level holographic data storage (HDS) systems by using a well-suited modulation code scheme. The HDS system is one of the most promising approaches for storing massive digital data for the next-generation optical data storage systems. However, the performance of retrieving data in the HDS system is severely affected by fatal interference (FI) patterns. The proposed coding design aims to get rid of all FI patterns during the recording procedure with reasonable computational complexity.

A novel design of de-free k-constraint low-density parity-check (LDPC) code is proposed in this study. The input user data is first converted into a k-constraint code using a nibble replacement method. After that, a guided scrambling (GS) technique and a (4,6) balance code are deployed together to construct de-free channel coded sequences. The designed de-free k constrained code is further combined with the LDPC code such that the modulation constraints are satisfied in both the systematic and parity parts. Simulation results show that the proposed design not only provides an improved bit-error-rate (BER) performance, but also achieves significant dc suppression.

This paper presents a 9/12 two-dimensional (2D) modulation code as a way to overcome 2D intersymbol interference (ISI) in bit-patterned media recording (BPMR) systems. BPMR systems are regarded as one of the promising candidates for the attainment of areal density increases that are beyond the capacities of conventional storage systems. The 2D ISI problem significantly degrades the system performance. The results show that the proposed modulation code offers a gain of approximately 2 dB over that of a system without encoding.

This paper presents a scheme that utilizes soft feedback information obtained from a decoder to eliminate detrimental interference in bit-patterned media recording (BPMR) systems. BPMR is a promising technology that can increase the storage area density of magnetic storage systems, but one of the main challenges is to overcome 2-D spatial interference. The performance of the proposed scheme is compared with that of a conventional iterative detection scheme, and the results indicate that the proposed model is better by approximately 1 dB at 20% track misregistration. In particular, the performance of the system is quite superior, allowing the design of systems with higher area densities.

This research proposes a new detection scheme using three extrinsic information resources supporting two-dimensional soft output Viterbi algorithm (2D SOVA) for bit patterned media recording (BPMR) that is well-known as a candidate for the next-generation magnetic storage system. The proposed method allows channel detection to improve its output with the help of the useful extrinsic information resources in each stage.