Performance Evaluation of Parallel Wi-Fi Redundancy with Deferral Techniques

TL;DR

This paper evaluates parallel Wi-Fi redundancy with deferral techniques in industrial environments, demonstrating its benefits for real-time control systems by analyzing real-world data to improve latency and spectrum efficiency.

Contribution

It provides a quantitative analysis of deferred parallel redundancy in Wi-Fi, highlighting its advantages for real-time applications in industrial settings.

Findings

Deferred parallel redundancy reduces worst-case transmission latency.

The approach consumes limited additional spectrum.

It is practically applicable in wireless control loops.

Abstract

Wireless communication is increasingly used in industrial environments, since it supports mobility of interconnected devices. Among the transmission technologies operating in unlicensed bands available to this purpose, Wi-Fi is certainly one of the most interesting, because of its high performance and the relatively low deployment costs. Unfortunately, its dependability is often deemed unsuitable for real-time control systems. In this paper, the use of parallel redundancy is evaluated from a quantitative viewpoint, by considering a number of performance indices that are relevant for soft real-time applications. Analysis is carried out on a large dataset acquired from a real setup, to provide realistic insights on the advantages this kind of approaches can provide. As will be seen, deferred parallel redundancy provides clear advantages in terms of the worst-case transmission latency, at limited costs concerning the amount of consumed spectrum. Hence, it can be practically exploited every time a wireless connection is included in a control loop.