For efficient modulation and error control coding, the deliberate flipping approach imposes the run-length-limited(RLL) constraint by bit error before recording. From the read side, a high coding rate limits the correcting capability of RLL bit error. In this paper, we study the low-density parity-check (LDPC) coding for RLL constrained recording system based on the Unequal Error Protection (UEP) coding scheme design. The UEP capability of irregular LDPC codes is used for recovering flipped bits. We provide an allocation technique to limit the occurrence of flipped bits on the bit with robust correction capability. In addition, we consider the signal labeling design to decrease the number of nearest neighbors to enhance the robust bit. We also apply the density evolution technique to the proposed system for evaluating the code performances. In addition, we utilize the EXIT characteristic to reveal the decoding behavior of the recommended code distribution. Finally, the optimization approach for the best distribution is proven by differential evolution for the proposed system.

翻译：为实现高效的调制与差错控制编码，采用主动翻转方法在记录前通过比特错误施加游程长度受限（RLL）约束。从读出端来看，高编码率限制了RLL比特错误的校正能力。本文基于非均衡差错保护（UEP）编码方案设计，研究面向RLL约束记录系统的低密度奇偶校验（LDPC）编码。利用非规则LDPC码的UEP能力恢复翻转比特，我们提出一种分配技术，将翻转比特限制在具有较强纠错能力的比特位置上。此外，考虑信号标记设计以减少最近邻数量，从而增强鲁棒比特的性能。采用密度演化技术对所提系统进行编码性能评估，并利用EXIT特性揭示所推荐码分布的译码行为。最终，通过差分进化算法证明所提系统最优分布的优化方法。