  A new type of spatially coupled low-density parity-check (SC-LDPC) codes
motivated by practical storage applications is presented. SC-LDPCL codes
(suffix 'L' stands for locality) can be decoded locally at the level of
sub-blocks that are much smaller than the full code block, thus offering
flexible access to the coded information alongside the strong reliability of
the global full-block decoding. Toward that, we propose constructions of
SC-LDPCL codes that allow controlling the trade-off between local and global
correction performance. In addition to local and global decoding, the paper
develops a density-evolution analysis for a decoding mode we call semi-global
decoding, in which the decoder has access to the requested sub-block plus a
prescribed number of sub-blocks around it. SC-LDPCL codes are also studied
under a channel model with variability across sub-blocks, for which
decoding-performance lower bounds are derived.
