  In this paper, we consider using simultaneous wireless information and power
transfer (SWIPT) to recharge the sensor in the LQG control, which provides a
new approach to prolonging the network lifetime. We analyze the stability of
the proposed system model and show that there exist two critical values for the
power splitting ratio {\alpha}. Then, we propose an optimization problem to
derive the optimal value of {\alpha}. This problem is non-convex but its
numerical solution can be derived by our proposed algorithm efficiently.
Moreover, we provide the feasible condition of the proposed optimization
problem. Finally, simulation results are presented to verify and illustrate the
main theoretical results.
