As the global demand for data has continued to rise exponentially, some have
begun turning to the idea of semantic communication as a means of efficiently
meeting this demand. Pushing beyond the boundaries of conventional
communication systems, semantic communication focuses on the accurate recovery
of the meaning conveyed from source to receiver, as opposed to the accurate
recovery of transmitted symbols. In this survey, we aim to provide a
comprehensive view of the history and current state of semantic communication
and the techniques for engineering this higher level of communication. A survey
of the current literature reveals four broad approaches to engineering semantic
communication. We term the earliest of these approaches classical semantic
information, which seeks to extend information-theoretic results to include
semantic information. A second approach makes use of knowledge graphs to
achieve semantic communication, and a third utilizes the power of modern deep
learning techniques to facilitate this communication. The fourth approach
focuses on the significance of information, rather than its meaning, to achieve
efficient, goal-oriented communication. We discuss each of these four
approaches and their corresponding studies in detail, and provide some
challenges and opportunities that pertain to each approach. Finally, we
introduce a novel approach to semantic communication, which we term
context-based semantic communication. Inspired by the way in which humans
naturally communicate with one another, this context-based approach provides a
general, optimization-based design framework for semantic communication
systems. Together, this survey provides a useful guide for the design and
implementation of semantic communication systems.Comment: 30 pages, 14 figures. This work has been submitted to the IEEE for
possible publication. Copyright may be transferred without notice, after
which this version may no longer be accessibl