  Bit-interleaved coded modulation (BICM) has attracted considerable attention
from the research community in the past three decades, because it can achieve
desirable error performance with relatively low implementation complexity for a
large number of communication and storage systems. By exploiting the iterative
demapping and decoding (ID), the BICM is able to approach capacity limits of
coded modulation over various channels. In recent years, protograph low-density
parity-check (PLDPC) codes and their spatially-coupled (SC) variants have
emerged to be a pragmatic forward-error-correction (FEC) solution for BICM
systems due to their tremendous error-correction capability and simple
structures, and found widespread applications such as deep-space communication,
satellite communication, wireless communication, optical communication, and
data storage. This article offers a comprehensive survey on the
state-of-the-art development of PLDPC-BICM and its innovative SC variants over
a variety of channel models, e.g., additive white Gaussian noise (AWGN)
channels, fading channels, Poisson pulse position modulation (PPM) channels,
and flash-memory channels. Of particular interest is code construction,
constellation shaping, as well as bit-mapper design, where the receiver is
formulated as a serially-concatenated decoding framework consisting of a
soft-decision demapper and a belief-propagation decoder. Finally, several
promising research directions are discussed, which have not been adequately
addressed in the current literature.
