More is less: Connectivity in fractal regions

Ad-hoc networks are often deployed in regions with complicated boundaries. We show that if the boundary is modeled as a fractal, a network requiring line of sight connections has the counterintuitive property that increasing the number of nodes decreases the full connection probability. We characterise this decay as a stretched exponential involving the fractal dimension of the boundary, and discuss mitigation strategies. Applications of this study include the analysis and design of sensor networks operating in rugged terrain (e.g. railway cuttings), mm-wave networks in industrial settings and vehicle-to-vehicle/vehicle-to-infrastructure networks in urban environments.Comment: 5 page

Wireless cloud networks for critical industrial quality control

The use of wireless network technology in the field of industrial quality and process control is becoming a remarkable research topic. This paper illustrates promising network architectures and transmission protocols to support next generation industrial wireless quality control systems. We consider a wireless communication scenario referred to as Wireless Cloud Network (WCN) where messages are flooded from sensors/actuators to Host station (and vice versa) through a self-contained dense network characterized by massively air-interacting ??cloud?? nodes. The WCN is designed to support the management of realtime critical industrial communication services. Particular focus is on quality control for oil and gas seismic exploration and closed loop networked control. Preliminary experiments based on IEEE 802.15.4 compliant devices show that the WCN system can provide clear performance advantages compared to conventional architectures in terms of control stability performance