Experimental Evaluation of Techniques to Lower Spectrum Consumption in Wi-Red

Seamless redundancy layered atop Wi-Fi has been shown able to tangibly increase communication quality, hence offering industry-grade reliability. However, it also implies much higher network traffic, which is often unbearable as the wireless spectrum is a shared and scarce resource. To deal with this drawback the Wi-Red proposal includes suitable duplication avoidance mechanisms, which reduce spectrum consumption by preventing transmission on air of inessential frame duplicates. In this paper, the ability of such mechanisms to save wireless bandwidth is experimentally evaluated. To this purpose, specific post-analysis techniques have been defined, which permit to carry out such an assessment on a simple testbed that relies on plain redundancy and do not require any changes to the adapters' firmware. As results show, spectrum consumption decreases noticeably without communication quality is impaired. Further saving can be obtained if a slight worsening is tolerated for latencies.Comment: preprint, 13 page

Increasing Safety Levels in Human-Machine Interaction by Beyond-5G Wireless Redundancy

Factory automation in the context of Industry 4.0/5.0 requires safety levels to satisfy more stringent and tight limits than those available so far. This goal is further challenged by the extension to the wireless environment of industrial shop floor communications that were traditionally based on cabled networks. Starting with wireless LANs, the trend towards the use of industrial wireless is fostered by the advent of fifth Generation (5G) private connectivity and is bound to increase its pace in the evolution towards 6G. In particular, the interaction of human operators with industrial robots and autonomous vehicles on the shop floor is posing stringent safety requirements that in turn push forward the dependability and reliability limits of wireless connectivity. To help achieve these limits, this paper proposes a dynamic redundancy mechanism based on the real-time activation/deactivation of radio bearers instantiated between mobile devices carried by humans and machines and multiple base stations, to achieve guaranteed upper bounds on packet loss probability in the communication of data related to operational safety control loops. An optimization problem is posed, and suitable heuristics are evaluated by simulation in a 5G and beyond wireless environment, aiming to dynamically maintain the required reliability levels with small computational effort