  This paper considers controlled scalar systems relying on a lossy wireless
feedback channel. In contrast with the existing literature, the focus is not on
the system controller but on the wireless transmit power controller that is
implemented at the system side for reporting the state to the controller. Such
a problem may be of interest, \emph{e.g.}, for the remote control of drones,
where communication costs may have to be considered. Determining the power
control policy that minimizes the combination of the dynamical system cost and
the wireless transmission energy is shown to be a non-trivial optimization
problem. It turns out that the recursive structure of the problem can be
exploited to determine the optimal power control policy. As illustrated in the
numerical performance analysis, in the scenario of a dynamics without
perturbations, the optimal power control policy consists in decreasing the
transmit power at the right pace. This allows a significant performance gain
compared to conventional policies such as the full transmit power policy or the
open-loop policy.
