τ ≈ τsc + τca (2)
Control mechanisms based on constant time delay are not suitable for NCS, since network delay is usually time varying [30]. When τ is less than the sampling period Ts, the stability condition of the NCS can be found by computing the upper bound of delay between any two successive sensor messages [32]–[35]. On the other hand, when τ is larger than the sampling period, some delay compensation technique must be employed. Various delay compensation techniques can be found in [34]. Networks with constant and independent delays have been developed and controller design with constant and random time delay have been discussed in [32]–[35].