Impact of Fading Channel Imposed Correlated Packet Drops on State Estimation in a Networked Control System: An Experimental Study Based on SDRs

Networked control systems are control systems with a wireless network back-end that enables seamless exchange of data between the individual subsystems. However, the wireless channel is inherently imperfect in nature and may often experience data losses, yet most literature overlooks the underlying causes of the same. Fading effect, among many other factors, stands out as a prominent cause with its distinct characteristics, including the possibility of correlated packet drops. Traditional methods are inadequate to analyze or solve the problem of state estimation in the presence of these correlated packet drops. In order to overcome the limitation of traditional methods and to enable a comprehensive analysis, we present a dedicated algorithm for a deterministic channel case which is basically derived from a more generalized theorem in [1] and our principal contribution lies in the development of a real-time transceiver system and the creation of a test-bed utilizing software-defined radios (SDRs) to replicate correlated losses induced by fading effect. With this emulator, we have tested the modified estimation algorithm presented and also we have analyzed its effectiveness in dealing with such drops.