Cyber-Physical Control over Wireless Sensor and Actuator Networks with Packet Loss

TL;DR

This paper analyzes the unreliability of wireless sensor and actuator networks in cyber-physical control systems, focusing on packet loss issues and evaluating prediction algorithms to improve reliability.

Contribution

It provides an analysis of wireless channel behavior in WSANs and evaluates prediction algorithms for packet loss compensation in control systems.

Findings

Wireless channels exhibit high packet loss rates.

Prediction algorithms can mitigate packet loss effects.

Simulation results offer insights into improving reliability.

Abstract

There is a growing interest in design and implementation of cyber-physical control systems over wireless sensor and actuator networks (WSANs). Thanks to the use of wireless communications and distributed architectures, these systems encompass many advantages as compared to traditional networked control systems using hard wirelines. While WSANs are enabling a new generation of control systems, they also introduce considerable challenges for quality-of-service (QoS) provisioning. In this chapter we examine some of the major QoS challenges raised by WSANs, including resource constraints, platform heterogeneity, dynamic network topology, and mixed traffic. These challenges make it difficult to fulfill the requirements of cyber-physical control in terms of reliability and real-time. The focus of this chapter is on addressing the problem of network reliability. Specifically, we analyze the behavior of wireless channels via simulations based on a realistic link-layer model. Packet loss rate (PLR) is taken as a major metric for the analysis. The results confirm the unreliability of wireless communications and the uncertainty of packet loss over WSANs. To tackle packet loss, we present a simple solution that can take advantage of existing prediction algorithms. Simulations are conducted to evaluate the performance of several classical prediction algorithms used for packet loss compensation. The results give some insights into how to deal with packet loss in cyber-physical control systems over unreliable WSANs.