Increasing LPWAN Scalability by Means of Concurrent Multiband IoT Technologies: An Industry 4.0 Use Case.

One of the most important challenges of the Internet of Things (IoT) in the next years will be the smooth incorporation of millions of smart devices into its communications paradigm. The greater coverage area of sub-1-GHz low-power wide area networks (LPWANs) makes them a suitable technology to easily encompass hundreds of end devices under a single base station. However, LPWAN inherent simplicity affects negatively on scalability, as these networks are not flexible enough to deal with a high number of nodes unless their traffic load is really low, which limits many potential use-cases. This paper analyzes the scalability issue in LPWAN and proposes the INTER-HARE protocol: a solution based on the use of concurrent multiband IoT technologies, where an 868-MHz LPWAN acts as transparent backhaul for a set of subnetworks working at 2.4 GHz. The implementation of the INTER-HARE protocol on a real IoT platform was assessed both in several laboratory testbeds and in a pilot developed in the premises of an industrial company, proving its suitability in non-delay sensitive monitoring applications with end devices scattered throughout the targeted area.