technique and time-stamped messages between sensor node
and controller node. The delay ca τ , however, is different from
sc τ for its unpredicted character (i.e., the controller node can
not know how long it will take the control signal to transmit to
the actuator node). So it is difficult to compensate this part of
delay ca τ .
Based on the above-mentioned method, the equation (20)
can be rewritten as: