  This paper explores the use of semantic knowledge inherent in the
cyber-physical system (CPS) under study in order to minimize the use of
explicit communication, which refers to the use of physical radio resources to
transmit potentially informative data. It is assumed that the acquired data
have a function in the system, usually related to its state estimation, which
may trigger control actions. We propose that a semantic-functional approach can
leverage the semantic-enabled implicit communication while guaranteeing that
the system maintains functionality under the required performance. We
illustrate the potential of this proposal through simulations of a swarm of
drones jointly performing remote sensing in a given area. Our numerical results
demonstrate that the proposed method offers the best design option regarding
the ability to accomplish a previously established task -- remote sensing in
the addressed case -- while minimising the use of radio resources by
controlling the trade-offs that jointly determine the CPS performance and its
effectiveness in the use of resources. In this sense, we establish a
fundamental relationship between energy, communication, and functionality
considering a given end application.
