We study spatially coupled LDPC codes that allow access to sub-blocks much smaller than the full code block. Sub-block access is realized by a semi-global decoder that decodes a chosen target sub-block by only accessing the target, plus a prescribed number of helper sub-blocks adjacent in the code chain. This paper develops a theoretical methodology for analyzing the semi-global decoding performance of spatially coupled LDPC codes constructed from protographs. The main result shows that semi-global decoding thresholds can be derived from certain thresholds we define for the single-sub-block graph. These characterizing thresholds are also used for deriving lower bounds on the decoder's performance over channels with variability across sub-blocks, which are motivated by applications in data-storage.
@article{arxiv.2010.10616,
title = {On the Decoding Performance of Spatially Coupled LDPC Codes with Sub-block Access},
author = {Eshed Ram and Yuval Cassuto},
journal= {arXiv preprint arXiv:2010.10616},
year = {2020}
}