A Channel-Aware Combinatorial Approach to Design High Performance Spatially-Coupled Codes
A Channel-Aware Combinatorial Approach to Design High Performance Spatially-Coupled Codes
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DOI：
10.1109/tit.2020.2979981
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发表时间：
2018-04
影响因子：
2.5
通讯作者：
Ahmed Hareedy;R. Wu;L. Dolecek
中科院分区：
文献类型：
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作者：
Ahmed Hareedy;R. Wu;L. Dolecek
由于其能力吸引力的性能及其复杂性/延迟优势，空间耦合（SC）代码是现代密集数据存储系统中最有吸引力的错误校正校正代码之一。 SC代码是通过对基础块代码进行分区并耦合分区组件来构建的。在这里，我们专注于基于循环的SC代码。最近，引入了最佳重叠（OO），循环功率优化器（CPO）方法，以构建添加剂白色高斯噪声（AWGN）和Flash通道的高性能SC代码。 OO阶段在SC代码的原理上运行，以得出最佳的分区，该分区最小化了破坏迭代解码下SC代码性能的图形对象的数量。然后，CPO优化了循环功率，以进一步降低该数字。由于代码图中有害对象的性质严重取决于感兴趣的渠道的特征，因此将OO-CPO方法扩展到构造具有内在内存的通道的SC代码并不是一个直接的任务。在本文中，我们解决了一个相关的扩展。我们为实用的1-D磁记录通道（即部分响应（PR）通道构建高性能SC代码。通过组合技术，我们仔细地构建和解决了OO分区的优化问题，重点关注PR渠道中感兴趣的对象。然后，我们自定义CPO，以进一步减少代码图中这些对象的数量。使用拟议的OO-CPO方法为PR通道设计的SC代码优于先前的先验最新SC代码，该代码的帧错误率（FER）和1.1 dB的数量级约为3个数量级（信噪比（FER）和1.1 dB）（ SNR）。更有趣的是，我们的SC代码在FER中超过相同长度和速率的结构性块代码，而SNR中的尺寸高于1.8个数量级。使用设计的OO-CPO方法设计的SC代码比相同参数的块代码设计的SC代码不仅在误差底部区域中明显，而且在瀑布区域中也明显。
Because of their capacity-approaching performance and their complexity/latency advantages, spatially-coupled (SC) codes are among the most attractive error-correcting codes for use in modern dense data storage systems. SC codes are constructed by partitioning an underlying block code and coupling the partitioned components. Here, we focus on circulant-based SC codes. Recently, the optimal overlap (OO), circulant power optimizer (CPO) approach was introduced to construct high performance SC codes for additive white Gaussian noise (AWGN) and Flash channels. The OO stage operates on the protograph of the SC code to derive the optimal partitioning that minimizes the number of graphical objects that undermine the performance of SC codes under iterative decoding. Then, the CPO optimizes the circulant powers to further reduce this number. Since the nature of detrimental objects in the graph of a code critically depends on the characteristics of the channel of interest, extending the OO-CPO approach to construct SC codes for channels with intrinsic memory is not a straightforward task. In this paper, we tackle one relevant extension; we construct high performance SC codes for practical 1-D magnetic recording channels, i.e., partial-response (PR) channels. Via combinatorial techniques, we carefully build and solve the optimization problem of the OO partitioning, focusing on the objects of interest in the case of PR channels. Then, we customize the CPO to further reduce the number of these objects in the graph of the code. SC codes designed using the proposed OO-CPO approach for PR channels outperform prior state-of-the-art SC codes by up to around 3 orders of magnitude in frame error rate (FER) and 1.1 dB in signal-to-noise ratio (SNR). More intriguingly, our SC codes outperform structured block codes of the same length and rate by up to around 1.8 orders of magnitude in FER and 0.4 dB in SNR. The performance advantage of SC codes designed using the devised OO-CPO approach over block codes of the same parameters is not only pronounced in the error floor region, but also in the waterfall region.