Evaluating the joint use of LoRaWAN and Bluetooth mesh to improve survivability for critical sensor applications

Wide area, wireless, IoT-based, distributed sensor systems can be employed in mixed criticality solutions for measurement/detection/signaling of emergencies, dangers, accidents, and disasters. All these scenarios require reliability, security, and safety. This work introduces and characterizes a new proposal to enhance existing LoRaWAN applications by adding a transparent redundant channel just for critical traffic. Network survivability and delivery success of critical messages, even with low LoRaWAN signal quality (as in indoors), is increased. The proposal preserves the LoRaWAN backend structure (including end-to-end security) using short-range radios to implement an underlying redundant mesh channel for transparently transporting LoRaWAN traffic of critical applications. Hybrid scenarios with legacy standard nodes coexisting are also permitted. The proof-of-concept combines LoRaWAN and, without losing generality, a redundant channel with Bluetooth mesh. This work includes: metrics definition, evaluation of complex scenario by means of simulations; and real experiments demonstrating feasibility and integration with LoRaWAN-compliant backend using commercial hardware/firmware/software. In particular, results confirm that packet loss in the order of 1% on the Bluetooth Mesh side can be obtained and therefore the critical traffic delivery success is improved by almost two orders of magnitude.