Wireless network based control with time varying delay

This paper describes a control scheme for a wireless networked system with variable time delay. Especially, the paper focuses on a packet based network in which subsequent packets catch up the preceding packet. The paper reveals that the forward delay and the backward delay, which are the delay from the local to the remote system and vice versa, are needed for the precise system identification and the control method. If only the round trip time is used, the identification and the control for time varying delay lead unexpected results. To measure the time delay, time synchronization of the local and remote system is required and this paper proposes to use a timing synchronization function (TSF) of IEEE 802.11 based wireless network Performance evaluation by simulation studies for system identification and delay compensated controller are shown. The simulation results verified that the proposed method effectively performed.