  We consider the joint design of packet forwarding policies and controllers
for wireless control loops where sensor measurements are sent to the controller
over an unreliable and energy-constrained multi-hop wireless network. For fixed
sampling rate of the sensor, the co-design problem separates into two
well-defined and independent subproblems: transmission scheduling for
maximizing the deadline-constrained reliability and optimal control under
packet loss. We develop optimal and implementable solutions for these
subproblems and show that the optimally co-designed system can be efficiently
found. Numerical examples highlight the many trade-offs involved and
demonstrate the power of our approach.
