  We consider a leader-follower formation control setup as an example for a
multi-agent networked control system (NCS). This paper proposes an event-based
wireless communication scheme with a MIMO precoder, that dynamically adapts to
both the channel and the current control state. We apply a Lyapunov drift
approach for optimizing the precoder and for defining an event-triggering
policy. To evaluate the performance of the proposed scheme, we simulate a
formation control of two unmanned aerial vehicles (UAVs) connected via a
point-to-point MIMO fading channel. Compared to a benchmark scheme with
periodic transmissions and a basic water-filling algorithm, we demonstrate that
our proposed event-based scheme is more efficient by consuming less energy and
requiring less frequent transmissions on average.
