Avoiding Delay Jitter in Cyber-Physical Systems Using One Way Delay Variations Model

Abstract

Delay jitter adversely affects the performance of networked real-time applications that require accurate prediction of packet delivery times. Delay jitter can be smoothed by holding packets in a play-back buffer for a certain time called a playback delay. In this paper, we propose a scheme to enhance the prediction of the play-back delay in networked control systems (NCSs) with no need for clock synchronization. Our newly proposed scheme differs from previous schemes by using the one way delay variation. We have studied the behavior of one way delay variation by conducting extensive measurements between 50 strategically located wired and wireless connected hosts. The advantage of our scheme is that it significantly improves handling of sudden delay spikes, provides a closer approximation to the round trip time (RTT), and exhibits less frequent outliers.