Optimized Wireless Connectivity for Cyber-Physical Systems with Publisher/Subscriber Architecture

Rapid advancements in communications technology accompanied by ever-increasing computing power and web-based cyber universe pave the way to new hyper-connectivity concepts and solutions among persons and things. In terms of connectivity, the IEEE 802.11 Wireless Local Area Network (WLAN), commonly referred to as Wi-Fi, has become a de-facto standard solution for the last-hop network access due to its high data rate, low cost, and ease of deployment. In this paper, we present a fast, robust and reliable application-specific context-aware Wi-Fi-based connectivity framework to facilitate the expansion of new use-cases in hyper-connected environments. We propose a configurable and flexible architecture for different network topology scenarios. The proposed solution dynamically exploits the presence of hierarchical infrastructure, ad-hoc and/or broadcast mode. We will focus on Industry 4.0 Cyber-Physical Systems (CPS) addressing a broad range of potential applications, with humans either included in or excluded from the control loop using publisher/subscriber message-exchange architecture and ROS (Robot Operating System). Optimized wireless connectivity scenarios will be analyzed, providing latency, throughput and reliability evaluations. We will argue in which situations the conventional non-optimized solutions would suffice over the newly proposed one. We evaluate and compare the efficacy of our solution on a carefully controlled, traffic-shaped wireless testbed consisting of four nodes using a Commercial Off-The-Shelf (COTS) 802.11 hardware. The obtained experimental results validate the feasibility and effectiveness of our proposed solution and demonstrate its advantages over the conventional non-optimized one.