  Recent advances in deep learning have led to increased interest in solving
high-efficiency end-to-end transmission problems using methods that employ the
nonlinear property of neural networks. These techniques, we call neural joint
source-channel coding (NeurJSCC), extract latent semantic features of the
source signal across space and time, and design corresponding variable-length
NeurJSCC approaches to transmit latent features over wireless communication
channels. Rapid progress has led to numerous research papers, but a
consolidation of the discovered knowledge has not yet emerged. In this article,
we gather diverse ideas to categorize the expansive aspects on NeurJSCC as two
paradigms, i.e., explicit and implicit NeurJSCC. We first focus on those two
paradigms of NeurJSCC by identifying their common and different components in
building end-to-end communication systems. We then focus on typical
applications of NeurJSCC to various communication tasks. Our article highlights
the improved quality, flexibility, and capability brought by NeurJSCC, and we
also point out future directions.
