  In this paper, we consider a MIMO networked control system with an energy
harvesting sensor, where an unstable MIMO dynamic system is connected to a
controller via a MIMO fading channel. We focus on the energy harvesting and
MIMO precoding design at the sensor so as to stabilize the unstable MIMO
dynamic plant subject to the energy availability constraint at the sensor.
Using the Lyapunov optimization approach, we propose a closed-form dynamic
energy harvesting and dynamic MIMO precoding solution, which has an
event-driven control structure. Furthermore, the MIMO precoding solution is
shown to have an eigenvalue water-filling structure, where the water level
depends on the state estimation covariance, energy queue and the channel state,
and the sea bed level depends on the state estimation covariance. The proposed
scheme is also compared with various baselines and we show that significant
performance gains can be achieved.
